Skip to content
AWC UI

Snackbar

Brief, low-priority feedback about something that just happened. It appears over the content, auto-hides after 4 seconds, and can carry a single action — canonically “Undo”.

Live preview Open in Storybook
Show snackbar
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<md-button variant="filled">Show snackbar</md-button>
<md-snackbar id="snack-preview" message="Message archived" action="Undo" closeable></md-snackbar>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-preview').show());
</script>

Install

Section titled “Install”

Already installed? See the Installation guide for one-time package setup (core + tokens, fonts). Each tab below shows two patterns for using md-snackbar in your project: Option A registers every AWC UI component at once (simplest), Option B imports only this component for tree-shake-friendly bundles. 

<!-- ─── Option A: global registration (all components) ─── -->
<script type="module">
  import '@awc-ui/core/define';
</script>


<!-- ─── Option B: single import (tree-shake only md-snackbar) ─── -->
<script type="module">
  import '@awc-ui/core/components/md-snackbar';
</script>


<md-snackbar></md-snackbar>

When to use

Section titled “When to use”
  • Confirming an action completed: “Message archived”, “Draft saved”.
  • Offering a single, reversing action — “Undo”.
  • Low-priority information the user can safely miss.

When not to use

Section titled “When not to use”
SituationUse instead
A decision that must block the flowmd-dialog
Critical errors the user must acknowledgemd-dialog
Explaining a controlmd-tooltip
Persistent statusInline text, md-chip, md-badge
A message needing an iconmd-dialog — M3 says avoid icons in snackbars
A message needing a linkAdd a button instead, or a different component
Several messages at onceQueue them — never stack or place them side by side
Form validationInline field errors

Message and action

Section titled “Message and action”

message is the label. action renders a text button — M3 forbids filled or elevated buttons here, so don’t slot one in. Keep the label to one line where possible (two on mobile).

One line, two lines, with and without an action Open in Storybook
Single line Single line + action Two lines Two lines + action
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<md-button variant="filled">Single line</md-button>
<md-button variant="filled">Single line + action</md-button>
<md-button variant="filled">Two lines</md-button>
<md-button variant="filled">Two lines + action</md-button>
<md-snackbar id="snack-single" message="File saved successfully"></md-snackbar>
<md-snackbar id="snack-action" message="Item deleted" action="Undo"></md-snackbar>
<md-snackbar id="snack-two" message="Your export finished and is ready to download from the reports page"></md-snackbar>
<md-snackbar id="snack-two-action" message="Your export finished and is ready to download from the reports page" action="Undo"></md-snackbar>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-single').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-action').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-two').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-two-action').show());
</script>

Each of the four is its own story: single line, single line + action, two lines, two lines + action.

Stacked

Section titled “Stacked”

stacked moves the action onto its own line. Use it when a long message and a long action would otherwise crowd each other.

Stacked action Open in Storybook
Stacked
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<md-button variant="filled">Stacked</md-button>
<md-snackbar id="snack-stacked" message="Item moved to trash and removed from all shared boards" action="Undo this move" closeable stacked></md-snackbar>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-stacked').show());
</script>

Close affordance and auto-hide

Section titled “Close affordance and auto-hide”

Auto-hide is on by default at 4000ms. closeable adds an X icon button.

Closeable, longer duration, and persistent Open in Storybook
Closeable Action + close Longer duration (10s) Persistent
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<md-button variant="filled">Closeable</md-button>
<md-button variant="filled">Action + close</md-button>
<md-button variant="filled">Longer duration (10s)</md-button>
<md-button variant="filled">Persistent</md-button>
<md-snackbar id="snack-close" message="Connection restored" closeable></md-snackbar>
<md-snackbar id="snack-action-close" message="Message archived" action="View" closeable></md-snackbar>
<md-snackbar id="snack-slow" message="Take your time reading this one" action="Undo" auto-hide-duration="10000" closeable></md-snackbar>
<md-snackbar id="snack-persist" message="No connection" action="Retry" auto-hide="false" closeable politeness="assertive" dismiss-label="Dismiss"></md-snackbar>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-close').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-action-close').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-slow').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-persist').show());
</script>

In Storybook: close icon only, action + close, and the non-dismissive case the callout above warns about.

Position

Section titled “Position”

position takes nine values. start and end are logical and mirror under RTL. M3: don’t place a snackbar flush to one edge of the layout, in front of navigation, or in front of / behind a FAB.

All nine positions Open in Storybook
top-start top top-end start center end bottom-start bottom bottom-end
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<md-button variant="outlined">top-start</md-button>
<md-button variant="outlined">top</md-button>
<md-button variant="outlined">top-end</md-button>
<md-button variant="outlined">start</md-button>
<md-button variant="outlined">center</md-button>
<md-button variant="outlined">end</md-button>
<md-button variant="outlined">bottom-start</md-button>
<md-button variant="filled">bottom</md-button>
<md-button variant="outlined">bottom-end</md-button>
<md-snackbar id="snack-ts" position="top-start" message="Top-start snackbar" closeable></md-snackbar>
<md-snackbar id="snack-t" position="top" message="Top snackbar" closeable></md-snackbar>
<md-snackbar id="snack-te" position="top-end" message="Top-end snackbar" closeable></md-snackbar>
<md-snackbar id="snack-s" position="start" message="Start snackbar" closeable></md-snackbar>
<md-snackbar id="snack-c" position="center" message="Center snackbar" closeable></md-snackbar>
<md-snackbar id="snack-e" position="end" message="End snackbar" closeable></md-snackbar>
<md-snackbar id="snack-bs" position="bottom-start" message="Bottom-start snackbar" closeable></md-snackbar>
<md-snackbar id="snack-b" position="bottom" message="Bottom snackbar (default)" closeable></md-snackbar>
<md-snackbar id="snack-be" position="bottom-end" message="Bottom-end snackbar" closeable></md-snackbar>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-ts').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-t').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-te').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-s').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-c').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-e').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-bs').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-b').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-be').show());
</script>

Slotted content

Section titled “Slotted content”

The default slot replaces message when you need light inline markup. Keep it plain text-ish — M3 forbids icons and inline links in a snackbar.

Slotted message content Open in Storybook
Slotted message File report.pdf uploaded
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<md-button variant="filled">Slotted message</md-button>
<md-snackbar id="snack-slotted" closeable>
  File <strong style="color: var(--md-sys-color-inverse-primary, #D0BCFF)">report.pdf</strong> uploaded
</md-snackbar>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-slotted').show());
</script>

The action and close slots let you supply your own controls when the built-in text button and icon button aren’t enough — but keep the action a text button.

There is no queue

Section titled “There is no queue”

One element shows one message. Showing two at once violates M3, so serialise them yourself: reuse a single md-snackbar, set message before each show(), and wait for mdClose before moving on.

One element, three queued messages
Fire three toasts One element, three messages — they show one after another.
Show code for each technology 
<md-snackbar id="bar" closeable></md-snackbar>

<script type="module">
import '@awc-ui/core/define';

const bar = document.getElementById('bar');
const queue = [];

window.toast = async function toast(message) {
  queue.push(message);
  if (queue.length > 1) return;
  while (queue.length) {
    bar.message = queue[0];
    bar.show();
    await new Promise((r) => bar.addEventListener('mdClose', r, { once: true }));
    queue.shift();
  }
};
</script>

Events

Section titled “Events”
EventCancelableDetailFires
mdOpennovoidShown
mdActionnovoidThe action button was used
mdCloseno{ reason: 'auto' | 'action' | 'close' }Hidden — branch on the reason

Why the action does not close it

Section titled “Why the action does not close it”

The action is not a dismiss button. Clicking it emits mdAction, leaves the snackbar open, and restarts the auto-hide timer. That is deliberate — an Undo that vanished the instant you pressed it would give you no confirmation that anything happened — but it means mdClose.detail.reason === 'action' is only reachable if you call hide('action') yourself.

So the two events are not interchangeable. mdAction says the button was pressed; mdClose says the snackbar is gone, and here is which of the three exits took it — 'action' from your own hide('action'), 'auto' from the timer, 'close' from the X icon or Escape. Only mdClose can tell those apart, which is why the commit belongs there.

You want to…Listen to
Reverse the operation (Undo was pressed)mdClose, detail.reason === 'action'
Commit the operation (it timed out or was dismissed)mdClose, reason is 'auto' or 'close'
React to the action button itself (analytics, a spinner)mdAction
Actually dismiss on the actioncall hide('action') from mdAction
Know it appearedmdOpen

All three events bubble and are composed, so one delegated listener on an ancestor catches every snackbar on the page.

Event log — press Undo, close it, or let it time out
Archive message Press Archive message, then press Undo, close it, or let it time out.
Show code for each technology 
<md-button variant="filled" id="show">Archive message</md-button>
<md-snackbar id="bar" message="Message archived" action="Undo" closeable></md-snackbar>

<script type="module">
import '@awc-ui/core/define';

const bar = document.getElementById('bar');

document.getElementById('show').addEventListener('click', () => bar.show());

bar.addEventListener('mdOpen', () => console.log('shown'));

// The action does not dismiss — close it with the matching reason.
bar.addEventListener('mdAction', () => bar.hide('action'));

bar.addEventListener('mdClose', (e) => {
  if (e.detail.reason === 'action') undoArchive();
  else commitArchive();
});
</script>

Wired against a real list — hold the pending row, and reverse it only when the close reason is action:

<md-snackbar id="bar" action="Undo" position="bottom-start"></md-snackbar>

<script type="module">
const bar = document.getElementById('bar');
let pending;

function archive(item) {
  hideRow(item);
  pending = item;
  bar.message = 'Message archived';
  bar.show();
}

// The action never self-dismisses — close it with the matching reason.
bar.addEventListener('mdAction', () => bar.hide('action'));

bar.addEventListener('mdClose', (e) => {
  if (e.detail.reason === 'action') restoreRow(pending);  // Undo pressed
  else commitArchive(pending);                            // auto / close
  pending = null;
});
</script>

API Reference

Section titled “API Reference”

Properties

PropertyAttributeTypeDefaultReflects
openopenbooleanfalseYes
messagemessagestring''—
actionactionstring''—
closeablecloseablebooleanfalseYes
autoHideauto-hidebooleantrue—
autoHideDurationauto-hide-durationnumber4000—
positionposition| 'bottom' | 'bottom-start' | 'bottom-end' | 'top' | 'top-start' | 'top-end' | 'start' | 'end' | 'center''bottom'Yes
stackedstackedbooleanfalseYes
politenesspoliteness'polite' | 'assertive''polite'Yes
dismissLabeldismiss-labelstring'Dismiss'—
densitydensity0 | -1 | -2 | -3 | -40Yes

Methods

MethodParameters
show()none
hide()reason: 'auto' | 'action' | 'close' = 'close'

Slots

SlotDescription
(default)—
actionCustom action element
closeCustom close element

CSS Custom Properties

Override on the host element for per-instance theming:

PropertyDescription
--md-snackbar-container-colorSurface background
--md-snackbar-message-colorSupporting text color
--md-snackbar-action-colorAction button text color
--md-snackbar-close-colorClose icon color
--md-snackbar-container-shapeBorder radius
--md-snackbar-min-widthMinimum inline size
--md-snackbar-max-widthMaximum inline size

CSS Shadow Parts

Style internal elements through shadow DOM with ::part():

PartDescription
surfaceOuter container
messageSupporting text wrapper
actionsAction button wrapper
closeClose button wrapper
close-icon—

Accessibility

Section titled “Accessibility”
  • The snackbar publishes to a live region; politeness controls interruption. Reserve assertive for genuinely urgent messages — it interrupts screen-reader users mid-sentence.
  • Auto-hide is a hazard for people who read slowly or use a screen reader. For anything with an action, consider a longer auto-hide-duration, and make sure the same action is reachable elsewhere in the UI.
  • Focus is not moved to the snackbar (correctly — it would be disruptive), so keyboard users may never reach the action. Never make a snackbar action the only route to an outcome.
  • politeness="polite" (the default) renders role="status" / aria-live="polite"; politeness="assertive" renders role="alert" / aria-live="assertive". Either way aria-atomic="true" makes the whole message re-announce rather than just the changed words.
  • Auto-hide pauses while you hover or keyboard-focus the surface and resumes when you leave — that is WCAG 2.2.1 (Timing Adjustable) being satisfied for you, so you rarely need to turn auto-hide off.
  • Escape closes it, but only when closeable is set — an X-less snackbar has no dismiss affordance to trigger.
  • Give the close affordance a localized dismiss-label (default "Dismiss").
  • Don’t let it obscure the element the user is working on.

Show the polite one below, then hover its surface and watch the four seconds stop counting. Tab into it — the timer stays paused, the close button announces its dismiss-label, and Escape dismisses it. The assertive one has no timer to pause (it sets auto-hide="false"), so use it to hear role="alert" interrupt instead.

Keyboard and screen-reader behaviour — hover to pause, Escape to close
polite (role=status) assertive (role=alert)
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<md-button variant="filled">polite (role=status)</md-button>
<md-button variant="outlined">assertive (role=alert)</md-button>
<md-snackbar id="snack-a11y-polite" message="Draft saved" action="Undo" closeable dismiss-label="Dismiss"></md-snackbar>
<md-snackbar id="snack-a11y-assertive" message="No connection" action="Retry" closeable politeness="assertive" auto-hide="false" dismiss-label="Dismiss notification"></md-snackbar>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-a11y-polite').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-a11y-assertive').show());
</script>

The assertive one sets auto-hide="false" and pairs it with closeable, exactly as the callout above insists — but “no auto-hide” only holds until its action is used. Press Retry and the component starts a 4000ms timer anyway, closing itself with reason === 'auto'. Handle mdAction yourself if a message must survive its own action.

RTL, density & i18n

Section titled “RTL, density & i18n”

RTL — the host is a full-viewport flex overlay, so position resolves against the writing direction the element inherits. Set dir on an ancestor and nothing else in the markup changes:

<div dir="rtl">
  <md-snackbar position="bottom-start" message="…" closeable></md-snackbar>
</div>

Press both and watch the corners swap — bottom-start is bottom-left under ltr and bottom-right under rtl. See the RTL story and RTL.

Same markup, dir=ltr vs dir=rtl
ltr
bottom-start
rtl
bottom-start
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<div style="display:grid;grid-template-columns:auto 1fr;gap:14px 16px;align-items:center">
  <span style="inline-size:3.5rem;opacity:.65;font-size:.75rem;font-family:ui-monospace,monospace;">ltr</span>
  <div dir="ltr" style="display:flex;flex-wrap:wrap;gap:12px;">
    <md-button variant="filled">bottom-start</md-button>
    <md-snackbar id="snack-rtl-a" position="bottom-start" message="dir=ltr — this lands bottom-left" closeable></md-snackbar>
  </div>
  <span style="inline-size:3.5rem;opacity:.65;font-size:.75rem;font-family:ui-monospace,monospace;">rtl</span>
  <div dir="rtl" style="display:flex;flex-wrap:wrap;gap:12px;">
    <md-button variant="filled">bottom-start</md-button>
    <md-snackbar id="snack-rtl-b" position="bottom-start" message="dir=rtl — this lands bottom-right" closeable></md-snackbar>
  </div>
</div>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-rtl-a').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-rtl-b').show());
</script>

Only the start / end positions mirror

Section titled “Only the start / end positions mirror”

Of the nine values, six carry a direction — start, end, top-start, top-end, bottom-start, bottom-end — and all six flip. The other three — top, bottom (the default) and center — are centred on the inline axis and look identical in both directions. Both rows below are inside dir="rtl".

Logical positions mirror, centred ones do not
mirrors
start end
neutral
bottom center
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<div dir="rtl" style="display:grid;grid-template-columns:auto 1fr;gap:14px 16px;align-items:center">
  <span style="inline-size:3.5rem;opacity:.65;font-size:.75rem;font-family:ui-monospace,monospace;">mirrors</span>
  <div style="display:flex;flex-wrap:wrap;gap:12px;">
    <md-button variant="filled">start</md-button>
    <md-button variant="filled">end</md-button>
    <md-snackbar id="snack-rtl-start" position="start" message="position=start — inline start, so the right edge here" closeable></md-snackbar>
    <md-snackbar id="snack-rtl-end" position="end" message="position=end — inline end, so the left edge here" closeable></md-snackbar>
  </div>
  <span style="inline-size:3.5rem;opacity:.65;font-size:.75rem;font-family:ui-monospace,monospace;">neutral</span>
  <div style="display:flex;flex-wrap:wrap;gap:12px;">
    <md-button variant="outlined">bottom</md-button>
    <md-button variant="outlined">center</md-button>
    <md-snackbar id="snack-rtl-bottom" position="bottom" message="position=bottom — centred, identical in both directions" closeable></md-snackbar>
    <md-snackbar id="snack-rtl-center" position="center" message="position=center — centred, identical in both directions" closeable></md-snackbar>
  </div>
</div>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-rtl-start').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-rtl-end').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-rtl-bottom').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-rtl-center').show());
</script>

Every density rung

Section titled “Every density rung”

Each rung compacts padding and text, taking the surface 48 → 45 → 42 → 39 → 36px tall. Width follows only until it meets --md-snackbar-min-width: in the demo below it goes 322 → 309 → 288px and then stops, because 288px is the floor.

Density 0 through -4 — one at a time, surface and text both taper
0
show
-1
show
-2
show
-3
show
-4
show
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<div style="display:grid;grid-template-columns:auto 1fr;gap:14px 16px;align-items:center">
  <span style="inline-size:3.5rem;opacity:.65;font-size:.75rem;font-family:ui-monospace,monospace;">0</span>
  <div style="display:flex;flex-wrap:wrap;gap:12px;">
    <md-button variant="filled">show</md-button>
    <md-snackbar id="snack-d0" density="0" message="Message archived at density 0" action="Undo" closeable></md-snackbar>
  </div>
  <span style="inline-size:3.5rem;opacity:.65;font-size:.75rem;font-family:ui-monospace,monospace;">-1</span>
  <div style="display:flex;flex-wrap:wrap;gap:12px;">
    <md-button variant="outlined">show</md-button>
    <md-snackbar id="snack-d1" density="-1" message="Message archived at density -1" action="Undo" closeable></md-snackbar>
  </div>
  <span style="inline-size:3.5rem;opacity:.65;font-size:.75rem;font-family:ui-monospace,monospace;">-2</span>
  <div style="display:flex;flex-wrap:wrap;gap:12px;">
    <md-button variant="outlined">show</md-button>
    <md-snackbar id="snack-d2" density="-2" message="Message archived at density -2" action="Undo" closeable></md-snackbar>
  </div>
  <span style="inline-size:3.5rem;opacity:.65;font-size:.75rem;font-family:ui-monospace,monospace;">-3</span>
  <div style="display:flex;flex-wrap:wrap;gap:12px;">
    <md-button variant="outlined">show</md-button>
    <md-snackbar id="snack-d3" density="-3" message="Message archived at density -3" action="Undo" closeable></md-snackbar>
  </div>
  <span style="inline-size:3.5rem;opacity:.65;font-size:.75rem;font-family:ui-monospace,monospace;">-4</span>
  <div style="display:flex;flex-wrap:wrap;gap:12px;">
    <md-button variant="outlined">show</md-button>
    <md-snackbar id="snack-d4" density="-4" message="Message archived at density -4" action="Undo" closeable></md-snackbar>
  </div>
</div>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-d0').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-d1').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-d2').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-d3').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-d4').show());
</script>

Density and direction together

Section titled “Density and direction together”

A global data-density ancestor and dir are independent signals, and a local density prop on one snackbar overrides the inherited rung without touching the direction. Below, dir="rtl" data-density="-1" wraps both; the second snackbar names -4 for itself and shrinks past its ancestor while still mirroring.

dir=rtl with data-density=-1, and one snackbar overriding to -4
inherits -1 local -4
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<div dir="rtl" data-density="-1" style="display:flex;flex-wrap:wrap;gap:12px;">
  <md-button variant="filled">inherits -1</md-button>
  <md-button variant="outlined">local -4</md-button>
  <md-snackbar id="snack-dd-a" position="bottom-start" message="dir=rtl, inherited density -1" action="Undo" closeable></md-snackbar>
  <md-snackbar id="snack-dd-b" position="top-start" density="-4" message="dir=rtl, local density -4" action="Undo" closeable></md-snackbar>
</div>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-dd-a').show());
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-dd-b').show());
</script>

Density — density="-1…-4" locally overrides the inherited data-density rung, taking the surface 48 → 36px tall. See Density.

i18n — translate message, action and dismiss-label. Translations run longer, so re-check M3’s one-line rule and consider stacked. The localization story switches all three at once.

Theming

Section titled “Theming”
Custom propertyPurposeDefault
--md-snackbar-container-colorSurfaceinverse-surface
--md-snackbar-container-shapeCorner radiuscorner-extra-small (4px)
--md-snackbar-message-colorLabelinverse-on-surface
--md-snackbar-action-colorAction button labelinverse-primary
--md-snackbar-close-colorClose affordanceinverse-on-surface
--md-snackbar-min-width / --md-snackbar-max-widthWidth bounds288px / 568px
Themed instance Open in Storybook
Themed snackbar
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<md-button variant="filled">Themed snackbar</md-button>
<md-snackbar id="snack-themed" message="Wider, squared, error-toned" action="Undo" closeable style="--md-snackbar-container-color: var(--md-sys-color-error); --md-snackbar-message-color: var(--md-sys-color-on-error); --md-snackbar-action-color: var(--md-sys-color-on-error); --md-snackbar-close-color: var(--md-sys-color-on-error); --md-snackbar-container-shape: 2px; --md-snackbar-max-width: 560px;"></md-snackbar>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-themed').show());
</script>

Check the result against the page behind it: the container is inverse-surface precisely so it reads as not part of the page, and a themed one has to keep that separation — the dark-theme story is the other half of that check.

CSS parts — surface, message, actions, close, plus close-icon, which the built-in close button re-exports (exportparts="icon:close-icon") so you can reach the glyph itself.

Use a part for what the custom properties cannot reach — border and radius on the surface, type style on the message, spacing between the controls:

::part() overrides Open in Storybook
Styled parts
Show code for each technology 
<!-- index.html — register the AWC UI elements once -->
<script type="module">
  import '@awc-ui/core/define';
</script>

<style>
  #snack-parts::part(surface) {
  border-radius: 16px;
  border: 2px solid var(--md-sys-color-outline-variant);
  }
  #snack-parts::part(message) { font-style: italic; }
  #snack-parts::part(actions) { gap: 16px; }
</style>
<md-button variant="filled">Styled parts</md-button>
<md-snackbar id="snack-parts" message="Styled with ::part()" action="Nice" closeable></md-snackbar>

<script type="module">
  // Give the trigger an id, then:
  // trigger.addEventListener('click', () => document.getElementById('snack-parts').show());
</script>
md-snackbar::part(message) {
  letter-spacing: 0.25px;
}

Keep the stock shape. Slight container transparency is fine if the text stays legible, but M3 warns against significantly altering the container shape.

Section titled “Related”

md-dialog · md-tooltip · md-button · md-icon-button · md-bottom-sheet · md-progress-indicator

AI / LLM Context

Section titled “AI / LLM Context”

For AI Agents — md-snackbar

Two artefacts to give your AI agent so it generates correct UI with this component. The per-component spec answers "how do I use this exact tag?". The main-llm spec answers "which tag should I pick in the first place?".

Per-component

md-snackbar spec card

Identity · when to use / when NOT · decision cues · behavioural contract · do/don't · anti-patterns · full API. Paste into your agent when you're implementing with this component.

Main-LLM spec

AWC UI Operator's Manual

System-prompt preamble · decision matrix · token reference · page recipes · anti-patterns. Paste into the system prompt at the start of a piece of work.

Open spec

md-snackbar readme.md 

# md-snackbar

<!-- llm:meta
tag: md-snackbar
category: containment
status: md3-mapped
m3-guidelines: https://m3.material.io/components/snackbar/guidelines
form-associated: false
depends-on: md-button, md-icon-button
used-by: none
-->

**Brief, low-priority feedback about something that just happened.** Appears
over the content, auto-hides after 4 seconds, and can carry a single action —
canonically "Undo".

> Setup, theming, density and i18n are configured once for the whole library —
> see [`main-llm.md`](../../../../../main-llm.md) at the repo root.

---

## When to use

- Confirming an action completed: "Message archived", "Draft saved".
- Offering a **single, reversing action** — "Undo".
- Low-priority information the user can safely miss.

## When NOT to use

| Situation | Use instead |
|---|---|
| A decision that must block the flow | `md-dialog` |
| Critical errors the user must acknowledge | `md-dialog` |
| Explaining a control | `md-tooltip` |
| Persistent status | Inline text, `md-chip`, `md-badge` |
| A message needing an icon | `md-dialog` — M3 says avoid icons in snackbars |
| A message needing a link | Add a button instead, or a different component |
| Several messages at once | Queue them — never stack or place side by side |
| Form validation | Inline field errors |

## Decision cues

| Need | Setting |
|---|---|
| Standard bottom placement | `position="bottom"` (default) |
| Corner placement on desktop | `position="bottom-start"` / `"bottom-end"` etc. |
| Vertically centred, fade only (no slide) | `position="start"` / `"end"` / `"center"` |
| Single reversing action | `action="Undo"` |
| Long message + action on its own line | `stacked` |
| Persist until dismissed | `auto-hide="false"` **and** `closeable` |
| Longer read time | `auto-hide-duration="8000"` |
| Urgent announcement | `politeness="assertive"` |

## API contract

The authoritative, generated property/event tables are at the bottom of this
file. This is the short form an implementer needs.

```html
<md-snackbar
  open                                             <!-- default: false -->
  message="Message archived"
  action="Undo"                                    <!-- empty = no action -->
  closeable                                        <!-- default: false -->
  auto-hide                                        <!-- default: true -->
  auto-hide-duration="4000"                        <!-- default: 4000 -->
  position="bottom|bottom-start|bottom-end|top|top-start|top-end|start|end|center"
                                                   <!-- default: bottom -->
  stacked                                          <!-- default: false -->
  politeness="polite|assertive"                    <!-- default: polite -->
  dismiss-label="Dismiss"                          <!-- default: Dismiss -->
  density="-1|-2|-3|-4"                            <!-- default: 0 (uncompacted) -->
></md-snackbar>
```

**Events** — all three are default Stencil events: they bubble and are
`composed`, so a single delegated listener on an ancestor catches every
snackbar.

| Event | Detail | Fires |
|---|---|---|
| `mdOpen` | `void` | Whenever `open` flips to true — including on first load if the element is rendered with `open` |
| `mdAction` | `void` | The built-in action button was clicked |
| `mdClose` | `{ reason: 'auto' \| 'action' \| 'close' }` | Dismissed — **check the reason** |

**Methods** — `show()`, `hide(reason?)` (both `async`; `reason` defaults to
`'close'`).

**Slots** — default (supporting text; *overrides* the `message` prop), `action`
(replaces the built-in text button), `close` (replaces the built-in X icon
button).

**Parts** — `surface`, `message`, `actions`, `close`. The built-in close button
re-exports its glyph as `close-icon`.

### Behavioral contract worth knowing

- **The action button does NOT dismiss the snackbar.** Clicking it emits
  `mdAction` and *restarts* the auto-hide timer. If the action should close the
  snackbar, call `hide('action')` yourself from your `mdAction` handler — that
  is the only way `reason: 'action'` is ever produced.
- **Setting `open = false` directly does not emit `mdClose`.** Only `hide()`,
  the auto-hide timer, and the built-in close button emit it. Use `hide()` when
  you want listeners to hear about it.
- Auto-hide is **on by default** at 4000 ms. `auto-hide="false"` without
  `closeable` leaves a snackbar the user cannot dismiss.
- **The auto-hide timer pauses while the surface is hovered or holds focus**
  (WCAG 2.2.1) and resumes on mouse-leave / focus-out.
- **Escape dismisses only when `closeable` is set.** The key listener is on
  `window` and is active only while the snackbar is open. A slotted `close`
  element does *not* enable Escape — set `closeable` for that.
- The built-in close button dismisses ~150 ms after the click, so its ripple
  finishes before the exit animation starts.
- The host is a **fixed, full-viewport overlay** with `pointer-events: none`;
  only the surface takes pointer events, and only while open. Put the element
  anywhere in the document — `position` decides where it lands, not the DOM
  position.
- Opening a snackbar lifts it above any snackbars already open (a small
  per-instance z-index offset), so the newest one is always on top regardless
  of markup order.
- Below 600 px viewport width the surface stretches to the full available width
  and the min/max width bounds are dropped, per M3.
- `position="start" | "end" | "center"` fade in place; the `top*` and `bottom*`
  positions slide in from that edge. All transitions are removed under
  `prefers-reduced-motion: reduce`.
- **There is no queue.** One element shows one message. Showing two at once
  violates M3 — serialise them yourself.
- `action` renders a `md-button variant="text"`. M3 forbids filled/elevated
  buttons here, so don't slot one in.

---

## Do / Don't

Sourced from [M3 · Snackbar · Guidelines](https://m3.material.io/components/snackbar/guidelines).

| ✅ Do | ❌ Don't |
|---|---|
| Keep the text label to one line where possible (two on mobile) | Don't write a paragraph |
| Offer "Undo" so users can amend a choice | A dismiss action is usually unnecessary — it hides itself |
| Extend the container width in wide layouts for longer labels | Don't place snackbars flush to one edge of the layout |
| Put an action on a third line if it's long (`stacked`) | Don't cram a long action beside a long message |
| Place it in front of the main content | Avoid placing snackbars in front of navigation components |
| Size it so focused elements stay visible | Don't fully cover elements in focus |
| Keep it clear of the FAB | Don't place a snackbar in front of **or** behind a FAB |
| Show one at a time | Don't stack them, place them side by side, or run them consecutively without spacing |
| Use a text button for the action | Don't use a filled or elevated button — it draws too much attention |
| Keep the label colour distinct from the action | The text label shouldn't share the action button's colour |
| Keep the stock shape; slight container transparency is fine if text stays legible | Don't significantly alter the container shape |
| Use a different component if you need an icon or a link | Avoid icons, stylised text, and inline links |
| Animate the snackbar alone | Don't animate other components (like the FAB) along with it |

---

## Patterns

```html
<md-snackbar id="bar" action="Undo" position="bottom-start"></md-snackbar>

<script type="module">
  const bar = document.getElementById('bar');
  let pending = null;

  function archive(item) {
    hideRow(item);
    pending = item;
    bar.message = 'Message archived';
    bar.show();
  }

  // The action button never closes the snackbar by itself — do it here, and
  // pass the reason so the mdClose handler can tell Undo from a timeout.
  bar.addEventListener('mdAction', () => bar.hide('action'));

  bar.addEventListener('mdClose', (e) => {
    if (e.detail.reason === 'action') restoreRow(pending);  // Undo pressed
    else commitArchive(pending);                            // auto / close
    pending = null;
  });
</script>
```

```html
<!-- Long message with the action on its own line -->
<md-snackbar stacked message="Your export finished and is ready to download"
             action="Download"></md-snackbar>

<!-- Persistent: must be closeable -->
<md-snackbar auto-hide="false" closeable message="Connection lost"
             politeness="assertive" dismiss-label="Dismiss"></md-snackbar>

<!-- Rich message via the default slot: it overrides `message` entirely -->
<md-snackbar id="rich">
  Saved to <strong>Drafts</strong>
</md-snackbar>
```

```js
// No built-in queue — serialise. Only hide(), the auto-hide timer and the
// built-in close button emit mdClose, so this loop only advances when the
// snackbar closes one of those ways. Never close it with `bar.open = false`:
// that emits nothing and the await below hangs forever.
const bar = document.getElementById('bar');
const queue = [];

async function toast(message) {
  queue.push(message);
  if (queue.length > 1) return;
  while (queue.length) {
    bar.message = queue[0];
    await bar.show();
    await new Promise((r) => bar.addEventListener('mdClose', r, { once: true }));
    queue.shift();
  }
}
```

## Anti-patterns

| ❌ Wrong | ✅ Right | Why |
|---|---|---|
| Expecting the action button to close the snackbar | Call `hide('action')` from your `mdAction` handler | The built-in action only emits `mdAction` and restarts the timer. |
| Committing the action in `mdAction` **and** `mdClose` | Branch on `mdClose.detail.reason` | You'll run it twice. |
| `el.open = false` and waiting for `mdClose` | Call `el.hide()` | A direct property write emits nothing. |
| Two snackbars visible at once | Queue them | M3 forbids stacking or side-by-side. |
| `auto-hide="false"` without `closeable` | Add `closeable` | Otherwise it's undismissable. |
| Slotting a `close` element and relying on Escape | Set `closeable` | Escape is gated on the `closeable` prop. |
| A filled button in the `action` slot | Text button only | M3 explicit rule. |
| An icon in the message | Use a dialog | M3 explicit rule. |
| An inline link in the message | Use the action button | M3 explicit rule. |
| A snackbar over the FAB or navigation | Reposition | M3 explicit rule (both in front and behind are wrong). |
| `politeness="assertive"` for routine confirmations | Keep `polite` | Assertive interrupts screen-reader users. |
| A snackbar for a critical error | `md-dialog` | It auto-hides and is easy to miss. |
| Nesting the snackbar inside a scrolling container to "position" it | Leave it anywhere and set `position` | The host is `position: fixed` over the viewport. |

## Accessibility, RTL, density, i18n

**Accessibility**
- `politeness="polite"` (default) renders `role="status"` + `aria-live="polite"`;
  `politeness="assertive"` renders `role="alert"` + `aria-live="assertive"`.
  Both set `aria-atomic="true"`, so the whole message is re-announced. Reserve
  `assertive` for genuinely urgent messages.
- Auto-hide is a hazard for users who read slowly or use a screen reader — for
  anything with an action, consider a longer `auto-hide-duration`, and make sure
  the same action is reachable elsewhere in the UI. Hover and keyboard focus
  pause the timer automatically.
- Focus is **not** moved to the snackbar (correctly — it would be disruptive),
  so keyboard users may never reach the action. Never make a snackbar action the
  only route to an outcome.
- Give the close affordance a localized `dismiss-label` (it becomes the icon
  button's `aria-label`).
- Don't let it obscure the element the user is working on.

**RTL** — the layout uses logical properties throughout, so `position="start"` /
`"end"` and the `*-start` / `*-end` corners mirror under `dir="rtl"`.

**Density** — `density="-1…-4"` locally overrides the inherited `data-density`
rung, compacting the surface height, padding and text. Rung `0` is the
uncompacted default and is inert — it does **not** opt a snackbar out of an
inherited rung; for that, set `style="--md-sys-density-scale: 0"` on the
element.

**i18n** — translate `message`, `action`, and `dismiss-label`. Translations run
longer, so re-check the one-line rule and consider `stacked`.

## Related components

`md-dialog` · `md-tooltip` · `md-button` · `md-icon-button` ·
`md-bottom-sheet` · `md-progress-indicator`

## Theming

| Custom property | Purpose | Default |
|---|---|---|
| `--md-snackbar-container-color` | Surface background | `--md-sys-color-inverse-surface` |
| `--md-snackbar-message-color` | Supporting-text colour | `--md-sys-color-inverse-on-surface` |
| `--md-snackbar-action-color` | Action label, icon and ripple | `--md-sys-color-inverse-primary` |
| `--md-snackbar-close-color` | Close-icon colour | `--md-sys-color-inverse-on-surface` |
| `--md-snackbar-container-shape` | Border radius | `--md-sys-shape-corner-extra-small` (4px) |
| `--md-snackbar-min-width` | Minimum inline size | `288px` |
| `--md-snackbar-max-width` | Maximum inline size | `568px` |

**CSS parts** — `surface`, `message`, `actions`, `close` (plus `close-icon`,
exported from the built-in close button).

```css
md-snackbar.wide {
  --md-snackbar-max-width: 720px;
}
```

<!-- Auto Generated Below -->


## Properties

| Property           | Attribute            | Description                                                                                                                                                                                                                                         | Type                                                                                                              | Default     |
| ------------------ | -------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------- | ----------- |
| `action`           | `action`             | Action button label (leave empty for no action)                                                                                                                                                                                                     | `string`                                                                                                          | `''`        |
| `autoHide`         | `auto-hide`          | Auto-dismiss after `autoHideDuration` ms (dismissive behavior)                                                                                                                                                                                      | `boolean`                                                                                                         | `true`      |
| `autoHideDuration` | `auto-hide-duration` | Time in ms before auto-dismiss                                                                                                                                                                                                                      | `number`                                                                                                          | `4000`      |
| `closeable`        | `closeable`          | Show a close (X) icon button                                                                                                                                                                                                                        | `boolean`                                                                                                         | `false`     |
| `density`          | `density`            | Local density rung. Drives the same `--md-sys-density-scale` signal that a global `data-density` ancestor sets, so a local value simply overrides the inherited one. 0 = default, -4 = ultra-compact.                                               | `-1 \| -2 \| -3 \| -4 \| 0`                                                                                       | `0`         |
| `dismissLabel`     | `dismiss-label`      | Accessible label for the close button. Localize per the page locale.                                                                                                                                                                                | `string`                                                                                                          | `'Dismiss'` |
| `message`          | `message`            | Primary supporting text                                                                                                                                                                                                                             | `string`                                                                                                          | `''`        |
| `open`             | `open`               | Whether the snackbar is visible                                                                                                                                                                                                                     | `boolean`                                                                                                         | `false`     |
| `politeness`       | `politeness`         | Live-region politeness. `'polite'` (default) → `role="status"` / `aria-live="polite"` (announced when idle). `'assertive'` → `role="alert"` / `aria-live="assertive"` — interrupts the screen reader; use sparingly for important / error messages. | `"assertive" \| "polite"`                                                                                         | `'polite'`  |
| `position`         | `position`           | Screen position                                                                                                                                                                                                                                     | `"bottom" \| "bottom-end" \| "bottom-start" \| "center" \| "end" \| "start" \| "top" \| "top-end" \| "top-start"` | `'bottom'`  |
| `stacked`          | `stacked`            | Stack action below text (for longer action labels)                                                                                                                                                                                                  | `boolean`                                                                                                         | `false`     |


## Events

| Event      | Description                                       | Type                                                      |
| ---------- | ------------------------------------------------- | --------------------------------------------------------- |
| `mdAction` | Emits when the action button is clicked           | `CustomEvent<void>`                                       |
| `mdClose`  | Emits when the snackbar is dismissed, with reason | `CustomEvent<{ reason: "auto" \| "close" \| "action"; }>` |
| `mdOpen`   | Emits when the snackbar becomes visible           | `CustomEvent<void>`                                       |


## Methods

### `hide(reason?: "auto" | "action" | "close") => Promise<void>`

Hide the snackbar with an optional reason

#### Parameters

| Name     | Type                            | Description |
| -------- | ------------------------------- | ----------- |
| `reason` | `"auto" \| "close" \| "action"` |             |

#### Returns

Type: `Promise<void>`



### `show() => Promise<void>`

Show the snackbar

#### Returns

Type: `Promise<void>`




## Slots

| Slot       | Description                                            |
| ---------- | ------------------------------------------------------ |
|            | Supporting text (overrides `message` prop)             |
| `"action"` | Custom action element (overrides `action` prop)        |
| `"close"`  | Custom close element (overrides default X icon button) |


## Shadow Parts

| Part        | Description             |
| ----------- | ----------------------- |
| `"actions"` | Action button wrapper   |
| `"close"`   | Close button wrapper    |
| `"message"` | Supporting text wrapper |
| `"surface"` | Outer container surface |


## Dependencies

### Depends on

- [md-button](../md-button)
- [md-icon-button](../md-icon-button)

### Graph
```mermaid
graph TD;
  md-snackbar --> md-button
  md-snackbar --> md-icon-button
  md-button --> md-ripple
  md-button --> md-loading-indicator
  md-icon-button --> md-ripple
  style md-snackbar fill:#f9f,stroke:#333,stroke-width:4px
```

----------------------------------------------

*Built with [StencilJS](https://stenciljs.com/)*

AWC UI Operator’s Manual 

# main-llm.md — AWC UI build director

<!-- llm:meta
role: director
audience: llm
library: "@awc-ui/core"
component-count: 57
sub-component-count: 24
manual-count: 81
per-component-docs: ./packages/core/src/components/<tag>/readme.md
-->

**You are building a web app with AWC UI, a Material Design 3 web-component
library.** This file is the entry point and the only document you need before
writing UI code. Everything here is self-contained: tokens, recipes,
composition rules and the ship checklist. Per-component detail lives in
`./packages/core/src/components/<tag>/readme.md` — e.g.
[`md-button`](./packages/core/src/components/md-button/readme.md).

Your job, in order:

1. **Interview** the user (§1). Do not skip it and do not guess.
2. **Lock the configuration** their answers imply (§2) and bootstrap it (§3–§4).
3. **Route every UI need through the decision matrix** (§5) — never pick a
   component by name-similarity.
4. **Load the component's readme.md before writing a single line of its
   markup** (§6). The file is
   `./packages/core/src/components/<tag>/readme.md` — read it in full, do not
   skim it, and do not write the markup from memory of a similar library. Each
   one has a `When NOT to use`, a `Do / Don't` table sourced from
   [m3.material.io](https://m3.material.io), and an `Anti-patterns` table of
   mistakes models actually make. If you are about to use three components,
   load all three readmes first.
5. **Check what nests inside what** (§7) and start from a recipe (§8) rather
   than from a blank page.
6. **Apply the universal rules** (§9) — the API, content and accessibility
   rules every component is bound by, and the ones §10 checks you against.
7. **Run the ship checklist** (§10) before declaring done.

**Fail closed.** If you cannot satisfy a step — no component fits, a token
doesn't exist, an accessible name has nowhere to come from — say so and ask.
Do not invent an `md-*` tag, a prop, or a token. If it is not in this file or
in the component's manual, it does not exist.

---

## §1 — Interview the user

Ask these **one at a time**, in this order. Each answer closes off decisions
downstream, so don't batch them into a wall of questions. Skip a question only
if the user has already answered it unprompted.

If the user says "just pick sensible defaults", use the **bold** option and tell
them what you chose.

### 1.1 Scope and shape

1. **What is the app?** One or two sentences — domain, primary job, who uses it.
2. **What kind of surface is it?**
   - Internal tool / admin console / dashboard
   - Data-heavy CRUD application
   - Consumer-facing product
   - Marketing or content site
   - Mobile-first / PWA
3. **Which framework?** React · Angular · Vue · Svelte · **plain HTML** ·
   Next · Nuxt · SvelteKit · Astro
4. **Does it server-render?** (SSR/SSG, or **client-only SPA**)
5. **Roughly how many distinct screens**, and what are the top 3?

### 1.2 Look and feel

6. **Density** — how much information per screen?
   - `0` — **default**, comfortable, touch-friendly
   - `-1` / `-2` — compact; typical for admin consoles
   - `-3` / `-4` — ultra-compact; dense data tables, trading/ops screens
7. **Theme** — light only, dark only, or **both with a user toggle**?
   Does it follow the OS preference?
8. **Brand color** — a seed/primary color, or **stock MD3 palette**?
9. **Expressive motion** — keep **ripple and shape-morph on** (default), or turn
   them off for a flatter, more utilitarian feel?
10. **Shape language** — **rounded** (MD3 default) or squared?

### 1.3 Internationalization

11. **How many locales**, and which?
12. **Any RTL locales** (Arabic, Hebrew, Farsi, Urdu)? — this changes layout
    verification and directional-icon handling.
13. **Which i18n engine?** (i18next, vue-i18n, ngx-translate, Paraglide, custom)
    Components are engine-agnostic — you localize in the consumer layer.
14. **Locale-formatted values** — dates, numbers, currency? Which locale drives
    `Intl`?

### 1.4 Data and forms

15. **Is there significant tabular data?** How many rows, and is it
    server-paged? (Drives how you page `md-table` — it holds the state, you
    supply each page of rows.)
16. **Are there charts?** Which questions should they answer?
17. **How heavy are the forms?** Validation rules, async validation, multi-step?
18. **Rich text editing anywhere?** — ⚠️ **AWC UI has no RTE component.** If yes,
    you must integrate a third-party editor (TipTap, Lexical, Quill) and style
    it to the MD3 tokens yourself. Confirm this with the user explicitly.

### 1.5 Constraints

19. **Accessibility target** — **WCAG 2.1 AA** (what the library is tested to),
    or stricter?
20. **Browser/device support floor?**
21. **Anything already decided** you must not change — existing design system,
    router, state library, CSS approach?

---

## §2 — Map answers to configuration

| Answer | What you set |
|---|---|
| Admin console / data-heavy | `data-density="-1"` or `-2` on `<html>`; prefer `size="xs"`/`"sm"` on actions |
| Consumer / marketing | leave density alone (`0` is the default); larger button sizes (`md`/`lg`) for CTAs |
| Mobile-first | `md-navigation-bar` + `md-fab`; avoid `md-navigation-rail`, `md-transfer-list`, wide tables |
| Desktop-first | `md-navigation-rail` or `md-app-bar`; rail over bottom bar |
| Dark mode | `data-theme="dark"` on `<html>`; wire a toggle, and mirror OS via `prefers-color-scheme` |
| Both themes with toggle | persist the choice; set the attribute before first paint to avoid a flash |
| Brand color | override the `--md-sys-color-*` roles in your own stylesheet, loaded after the tokens (§4.2) |
| Flat / utilitarian | `data-ripple="off"` and `data-shape-morph="off"` on `<html>` |
| Any RTL locale | `dir="rtl"` on `<html>`; add `mirror-icon` to `md-button`s with directional glyphs; swap the glyph name yourself everywhere else (§4.5) |
| Multiple locales | build a dictionary in the consumer layer and feed component text props from it; never hardcode strings in markup |
| `Intl`-formatted values | pass a `locale` prop where a component exposes one; format everything else before it reaches the component |
| SSR | import from `@awc-ui/core/hydrate` on the server; use the client/server wrappers in `@awc-ui/react` |
| Heavy forms | components are form-associated via `ElementInternals` — use a real `<form>`, `md-button type="submit"`, and native `required` (§4.7) |
| Rich text | integrate a third-party editor; there is no `md-rich-text` |

### 2.1 Global switches — the complete set

All are attributes on `<html>` (or any ancestor; the nearest one wins).

```html
<html
  lang="en"
  dir="ltr"                  <!-- or rtl -->
  data-theme="dark"          <!-- omit for light -->
  data-density="-1"          <!-- -1 … -4; see below -->
  data-ripple="off"          <!-- default on -->
  data-shape-morph="off"     <!-- default on -->
>
```

**`data-density="0"` is inert.** No `[density="0"]` rule exists — density `0` is
simply the base values on `:root`, and a `0` rule would pin them onto every
element (reflected props write `density="0"` almost everywhere) and break global
inheritance. So the *overriding* range is `-1 … -4`. To escape an inherited rung
for one subtree, reset the scale directly:

```css
.opt-out-of-density { --md-sys-density-scale: 0; }
```

Per-component overrides beat the global one: a `density` prop, or
`ripple="off"` / `shape-morph="off"` on the element. **53 of the 57 top-level
components expose a `density` prop.** The four that don't: `md-divider`,
`md-ripple`, `md-sparkline`, `md-tabs`. (Nine sub-components also lack one —
they inherit density from the parent that owns their layout.)

---

## §3 — Install and bootstrap

```bash
npm install @awc-ui/core
```

**Register everything (recommended).** Two imports, once per app entry — one
defines every component, one loads the tokens. Both come from `@awc-ui/core`
itself, so this path needs no second package:

```ts
import { defineCustomElements } from '@awc-ui/core/loader';
import '@awc-ui/core/css/tokens.css';

defineCustomElements(window);
```

`@awc-ui/core/css/tokens.css` is the complete, self-contained token sheet —
light and dark colour roles, shape, elevation, motion, typescale, spacing and
z-index. It is the same set documented in §4.1.

**One-line alternative.** `@awc-ui/core/define` does both steps in a single
import. It loads the package's own token sheet, so it needs nothing else
installed:

```ts
import '@awc-ui/core/define'; // defines every component + loads the token sheet
```

`define` is client-only (it eval-guards `window`) and, because it imports CSS,
it needs a bundler. Never import it into a server graph.

**Per-component registration**, for size-sensitive bundles — load the token
sheet once yourself:

```ts
import '@awc-ui/core/css/tokens.css';
import '@awc-ui/core/components/md-button';
import '@awc-ui/core/components/md-text-field';
```

**Framework wrappers** — use these instead of raw elements; they handle
registration, typed props, and event binding. Below the version floor, drop to
the raw custom elements and the `loader` import above.

| Framework | Package | Requires |
|---|---|---|
| React / Next | `@awc-ui/react` | React 18+ |
| Angular | `@awc-ui/angular` (`AwcUiModule`) | Angular 17+ |
| Vue / Nuxt | `@awc-ui/vue` | Vue 3 |
| Svelte / SvelteKit | `@awc-ui/svelte` | Svelte 4+ |
| Plain HTML / Astro | `@awc-ui/core/loader` | — |

**SSR** — `@awc-ui/core/hydrate` renders Declarative Shadow DOM on the server.
`@awc-ui/react` ships matching client/server wrappers. Keep `define` and
`loader` out of the server graph; both are browser entries.

**Fonts** — components expect Roboto and Material Symbols Outlined to be
available. The library does **not** inject them. Every `icon="…"` prop renders a
Material Symbols glyph inside shadow DOM, so the font must be registered at the
**document** level (font registration crosses shadow boundaries; class rules do
not — the components declare the class rule inside their own roots):

```html
<link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined">
<link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;500&display=swap">
```

To swap the whole library to a different Material Symbols cut, set
`--md-sys-icon-font-family` on `:root` and load the matching `@font-face`.

---

## §4 — Global configuration reference

### 4.1 The token system

All AWC UI styling resolves to design tokens. **Never hardcode hex colours,
pixel radii, shadows, or font stacks** — they break theming, dark mode, density
and RTL in one stroke. Every value below is a real custom property defined by
`@awc-ui/tokens`; you may read them, and you may override them.

#### Color roles

Light is the default; `[data-theme="dark"]` swaps the palette. Every role has a
matching `on-` role for content drawn on top of it.

| Token | Light | Dark | Typical usage |
|---|---|---|---|
| `--md-sys-color-primary` | `#6750A4` | `#D0BCFF` | Filled buttons, active states |
| `--md-sys-color-on-primary` | `#FFFFFF` | `#381E72` | Text/icons on primary |
| `--md-sys-color-primary-container` | `#EADDFF` | `#4F378B` | FAB, selected segments |
| `--md-sys-color-on-primary-container` | `#21005D` | `#EADDFF` | Text on primary-container |
| `--md-sys-color-secondary` | `#625B71` | `#CCC2DC` | Secondary accents |
| `--md-sys-color-secondary-container` | `#E8DEF8` | `#4A4458` | Tonal buttons, chips |
| `--md-sys-color-tertiary` | `#7D5260` | `#EFB8C8` | Tertiary accents |
| `--md-sys-color-tertiary-container` | `#FFD8E4` | `#633B48` | Tertiary surfaces |
| `--md-sys-color-error` | `#B3261E` | `#F2B8B5` | Error / destructive |
| `--md-sys-color-on-error` | `#FFFFFF` | `#601410` | Content on error |
| `--md-sys-color-error-container` | `#F9DEDC` | `#8C1D18` | Error surfaces |
| `--md-sys-color-surface` | `#FFFBFE` | `#1C1B1F` | Page / card background |
| `--md-sys-color-on-surface` | `#1C1B1F` | `#E6E1E5` | Body text |
| `--md-sys-color-surface-variant` | `#E7E0EC` | `#49454F` | Muted fills |
| `--md-sys-color-on-surface-variant` | `#49454F` | `#CAC4D0` | Secondary text, icons |
| `--md-sys-color-surface-container-lowest` | `#FFFFFF` | `#0F0D13` | Lowest surface tier |
| `--md-sys-color-surface-container-low` | `#F7F2FA` | `#1D1B20` | Card / elevated button bg |
| `--md-sys-color-surface-container` | `#F3EDF7` | `#211F26` | Default container tier |
| `--md-sys-color-surface-container-high` | `#ECE6F0` | `#2B2930` | Dialog / menu surfaces |
| `--md-sys-color-surface-container-highest` | `#E6E0E9` | `#36343B` | Highest surface tier |
| `--md-sys-color-outline` | `#79747E` | `#938F99` | Borders (3:1 contrast) |
| `--md-sys-color-outline-variant` | `#CAC4D0` | `#49454F` | Dividers (low contrast) |
| `--md-sys-color-inverse-surface` | `#313033` | `#E6E1E5` | Snackbar, inverse chips |
| `--md-sys-color-inverse-on-surface` | `#F4EFF4` | `#313033` | Content on inverse-surface |
| `--md-sys-color-scrim` | `#000000` | `#000000` | Modal scrims |

**Semantic status roles** — beyond the baseline M3 palette, the library adds
`success`, `warning` and `info`, each with `on-`, `-container` and
`on-…-container` companions, in both themes, AA-verified. Used by `md-chip`,
`md-badge`, `md-meter`, `md-status-dot`.

| Token | Light | Dark |
|---|---|---|
| `--md-sys-color-success` | `#2E6B4F` | `#9DD5B0` |
| `--md-sys-color-success-container` | `#B8F0CE` | `#14512F` |
| `--md-sys-color-warning` | `#7A5900` | `#EFC148` |
| `--md-sys-color-warning-container` | `#FFDF9B` | `#5C4200` |
| `--md-sys-color-info` | `#38608F` | `#A2C9FE` |
| `--md-sys-color-info-container` | `#D3E4FF` | `#1E4975` |

#### Shape tokens

| Token | Value | Typical usage |
|---|---|---|
| `--md-sys-shape-corner-none` | `0px` | Square edges |
| `--md-sys-shape-corner-extra-small` | `4px` | Snackbar, small chips |
| `--md-sys-shape-corner-small` | `8px` | Cards (outlined), small surfaces |
| `--md-sys-shape-corner-medium` | `12px` | Cards (default), inputs |
| `--md-sys-shape-corner-large` | `16px` | Dialogs, large cards |
| `--md-sys-shape-corner-extra-large` | `28px` | Bottom sheets |
| `--md-sys-shape-corner-full` | `9999px` | Buttons, chips, FAB |

Partial-corner variants also exist for surfaces that meet an edge:
`--md-sys-shape-corner-extra-small-top`, `-large-top`, `-large-end`,
`-extra-large-top`. Their values are four-value `border-radius` shorthands
(e.g. `16px 16px 0px 0px`), so assign them to `border-radius`, not to a single
corner.

#### Elevation tokens

`-0` is the keyword `none`; `-1` through `-5` are complete `box-shadow` values,
and those five are **re-declared with deeper shadows under `[data-theme="dark"]`**
— so always use the token rather than copying its value.

| Token | When |
|---|---|
| `--md-sys-elevation-0` | `none` — resting cards, flat surfaces |
| `--md-sys-elevation-1` | Elevated buttons and cards at rest |
| `--md-sys-elevation-2` | Hover bump |
| `--md-sys-elevation-3` | FAB, menus, dialogs at rest |
| `--md-sys-elevation-4` – `-5` | Reserved for the most prominent surfaces |

#### Motion tokens

Durations come in four families of four: `short1…4` (50/100/150/200ms),
`medium1…4` (250/300/350/400ms), `long1…4` (450/500/550/600ms), and
`extra-long1…4` (700/800/900/1000ms).

| Token | Value | When |
|---|---|---|
| `--md-sys-motion-duration-short2` | `100ms` | Buttons, ripples, state layers |
| `--md-sys-motion-duration-medium2` | `300ms` | Dialogs, sheets, menus |
| `--md-sys-motion-duration-long2` | `500ms` | Large surface transitions |
| `--md-sys-motion-duration-extra-long1` | `700ms` | Ambient / chart entrances |
| `--md-sys-motion-easing-standard` | `cubic-bezier(0.2, 0, 0, 1)` | Small utility transitions |
| `--md-sys-motion-easing-standard-accelerate` | `cubic-bezier(0.3, 0, 1, 1)` | Exits |
| `--md-sys-motion-easing-standard-decelerate` | `cubic-bezier(0, 0, 0, 1)` | Entrances |
| `--md-sys-motion-easing-emphasized` | `cubic-bezier(0.2, 0, 0, 1)` | Expressive transitions |
| `--md-sys-motion-easing-emphasized-accelerate` | `cubic-bezier(0.3, 0, 0.8, 0.15)` | Expressive exits |
| `--md-sys-motion-easing-emphasized-decelerate` | `cubic-bezier(0.05, 0.7, 0.1, 1)` | Expressive entrances |
| `--md-sys-motion-easing-linear` | `linear` | Progress, indeterminate loops |

> `--md-sys-motion-easing-emphasized` deliberately equals the standard curve:
> the full M3 emphasized curve is a two-phase path interpolator that CSS cannot
> express. The accelerate and decelerate halves *are* expressible, and are the
> ones to reach for.

MD3 Expressive also ships spring pairs, each an easing plus its natural
duration: `--md-sys-motion-spring-{spatial,effects}-{fast,default,slow}-easing`
and `…-duration`. Spatial = position/size/shape; effects = colour/opacity.

#### State-layer opacities

| Token | Value |
|---|---|
| `--md-sys-state-hover-state-layer-opacity` | `0.08` |
| `--md-sys-state-focus-state-layer-opacity` | `0.12` |
| `--md-sys-state-pressed-state-layer-opacity` | `0.12` |
| `--md-sys-state-dragged-state-layer-opacity` | `0.16` |
| `--md-sys-state-disabled-container-opacity` | `0.12` |
| `--md-sys-state-disabled-content-opacity` | `0.38` |

#### Typography, spacing and layering

- **Typescale** — `--md-sys-typescale-<role>-<size>-*` for
  `display`/`headline`/`title`/`label`/`body` × `large`/`medium`/`small`. Each
  role exposes `-font-family`, `-font-size`, `-line-height`, `-font-weight`,
  `-letter-spacing`, plus a `-font` shorthand
  (e.g. `--md-sys-typescale-headline-medium-font: 400 28px/36px Roboto, sans-serif`).
  Use the shorthand on the `font` property for headings you write yourself.
- **Spacing** — a 4px scale that tightens with density:
  `--md-sys-spacing-inset-{xs,sm,md,lg,xl}` (internal padding, 4/8/12/16/24px)
  and `--md-sys-spacing-gap-{xs,sm,md,lg}` (between siblings, 4/8/12/16px), plus
  `--md-sys-spacing-row-height` (`56px` at density 0).
- **Layering** — `--md-sys-z-index-app-bar` (100), `-navigation` (200),
  `-bottom-sheet` (300), `-popup` (1000), `-dialog-scrim` (1001), `-tooltip`
  (1500), `-snackbar` (2000). Use these instead of inventing z-indexes, or your
  overlay will land under a menu.

### 4.2 Theming and rebranding

To rebrand, redefine the role variables **after** the tokens stylesheet — both
themes, or dark mode inherits your light brand colour:

```css
:root {
  --md-sys-color-primary: #00629E;
  --md-sys-color-on-primary: #FFFFFF;
  --md-sys-color-primary-container: #CFE5FF;
  --md-sys-color-on-primary-container: #001D33;
}
[data-theme="dark"] {
  --md-sys-color-primary: #9BCBFF;
  --md-sys-color-on-primary: #003354;
  --md-sys-color-primary-container: #004A78;
  --md-sys-color-on-primary-container: #CFE5FF;
}
```

Per-component knobs are `--md-<component>-*` custom properties, listed in each
manual's Theming section (`--md-button-container-color`,
`--md-card-container-shape`, …). Prefer those over `::part()`, and prefer
`::part()` over reaching into shadow internals, which are unstable and will
break on any release.

**Overriding a colour role forfeits the library's contrast testing.** Re-verify
AA (4.5:1 text, 3:1 borders and dividers) after any palette change. The Theme
Generator at <https://awc-ui.dev/theme-generator> takes a seed colour, emits both
palettes as `--md-sys-color-*` overrides, and runs the WCAG checks live — use it
rather than hand-picking container and `on-` pairs.

### 4.3 Density

`data-density` steps `-1 → -4`; each rung trims ~4px of padding and touch
target, driving `--md-sys-density-scale` and the spacing tokens. `-4` is the
floor. Set it globally, override locally with the `density` prop. Do not go
below `-2` on touch-primary surfaces — you will break the 48px target.

Two details that bite:

- **`density="0"` does nothing** — see §2 for why, and for the
  `--md-sys-density-scale: 0` escape hatch.
- **`md-table` accepts two vocabularies**: the semantic `compact` / `standard` /
  `comfortable` (row heights 36 / 52 / 60px) *and* the numeric rungs. They
  compose — `density="compact"` inside a `data-density="-2"` region condenses
  further.

### 4.4 Dark mode

Set `data-theme="dark"` on `<html>` (or any ancestor — the nearest wins). The
tokens swap automatically and inherit across every shadow boundary; no
per-component code. To mirror the OS, read `prefers-color-scheme` and write the
attribute **before first paint**, or the page flashes light.

### 4.5 RTL

Layout is written with CSS logical properties, so it flips with `dir="rtl"`
without extra work. Two things still need you:

- **Directional glyphs do not flip.** Material Symbols are not auto-mirrored.
  `md-button` has a `mirror-icon` prop that mirrors its own leading/trailing
  glyph — set it on buttons using arrows, chevrons, `send`, `reply`, and leave
  it off for `add`, `search`, `favorite`. **`mirror-icon` exists only on
  `md-button`.** Everywhere else — `md-icon-button icon="…"`, `md-list-item`
  leading/trailing icons, `md-app-bar leading-icon` — swap the glyph name
  yourself (`arrow_back` ↔ `arrow_forward`).
- **Icon props you supply yourself** — e.g. `md-transfer-list`'s
  `move-right-icon` / `move-left-icon` / `move-all-*-icon` — must be swapped by
  you when the direction flips.

Never write physical CSS (`margin-left`, `padding-right`, `left`) around these
components. Use `margin-inline-start`, `padding-inline-end`, `inset-inline-end`.

### 4.6 Internationalization

Components are **i18n-engine-agnostic by design**. Every user-visible string is
either slotted content or a prop. Localize in the consumer layer: resolve your
dictionary to plain strings, then pass them in. Do not add a translation engine
inside a component. `locale` props exist only where a component computes an
`Intl`-formatted value itself: `md-date-picker`, `md-number-field`,
`md-meter`, `md-dialog`, and the charts (`md-bar-chart`, `md-line-chart`,
`md-area-chart`, `md-pie-chart`). `md-time-picker` has no
`locale` prop — it takes `format="12h" | "24h"` instead.

Templated strings keep their placeholder tokens when translated — translate
around the braces, don't remove them:

```html
<md-transfer-list count-template="{checked} / {total} ausgewählt"></md-transfer-list>
```

Other templated props: `md-autocomplete status-template`, `md-otp-field
cell-label-template`. Default prop values are English (`Search`, `Dismiss`,
`No results`, `Move selected to target`, …) — every one of them needs
translating in a localized app.

### 4.7 Forms and validation

Fourteen components are form-associated via `ElementInternals`, so they
participate in `FormData` and constraint validation like native controls:

`md-text-field` · `md-number-field` · `md-otp-field` · `md-select` ·
`md-multi-select` · `md-autocomplete` · `md-checkbox` · `md-radio` ·
`md-switch` · `md-slider` · `md-rating` · `md-date-picker` · `md-time-picker` ·
`md-button`

Rules:

- Use a real `<form>`. `md-button type="submit"` calls `form.requestSubmit()`
  (not `submit()`), so the `submit` event fires **and** built-in constraint
  validation runs. `required` genuinely blocks submit.
  `md-button type="reset"` calls `form.reset()`.
- Give every control a `name`, or it will not appear in `FormData`.
- Do **not** add hidden `<input>`s to mirror values — that's the old pattern and
  it double-submits.
- Validity changes are announced on a `mdValidityChange` event on the control.
  Error presentation is `error` + `error-text` on the field.
- Boolean state props differ by control — `md-checkbox` uses `checked`,
  `md-switch` uses **`selected`**, `md-select-option` uses `selected`. Check the
  manual; guessing `checked` on a switch silently does nothing.

---

## §5 — Component decision matrix

Route by **need**, not by name. If the need isn't listed, find the closest row
and read that component's `When NOT to use`.

### 5.1 Actions

| Need | Use | Don't use |
|---|---|---|
| Discrete labelled action | `md-button` | `md-chip`, raw `<button>` |
| Icon-only action | `md-icon-button` | `md-button` with no label |
| A destructive action | `md-button` + `md-dialog` to confirm | an unconfirmed `filled` button |
| The single most prominent screen action (mobile) | `md-fab` | a second `filled` `md-button` |
| One prominent action that expands to several | `md-fab-menu` + `md-fab-menu-item` | a stack of FABs |
| Primary action + variants of it | `md-split-button` | button + separate menu |
| 2–5 related actions as one unit | `md-button-group` | loose adjacent buttons |
| Mutually exclusive view/mode switch | `md-segmented-button-set` + `md-segmented-button` | radio buttons, tabs |
| Overflow / contextual actions | `md-menu` + `md-menu-item` | a row of text buttons |

### 5.2 Text input

| Need | Use | Don't use |
|---|---|---|
| Any single-line or multi-line text entry | `md-text-field` | raw `<input>` |
| A number with steppers and locale formatting | `md-number-field` | `md-text-field type="number"` |
| A one-time code / PIN | `md-otp-field` | a row of text fields |
| Text entry with suggestions | `md-autocomplete` | `md-select` |
| Site/app-wide search with a results surface | `md-search` | `md-text-field` with an icon |

### 5.3 Selection

| Need | Use | Don't use |
|---|---|---|
| One of many, from a list | `md-select` + `md-select-option` | radio group over ~7 options |
| One of few (2–5), all visible | `md-radio` | `md-select` |
| Several of many | `md-multi-select` | many `md-checkbox`es |
| Several of few, all visible | `md-checkbox` | `md-multi-select` |
| Instant on/off setting | `md-switch` | `md-checkbox` |
| A value in a numeric range | `md-slider` | `md-text-field type=number` |
| Subjective score | `md-rating` | slider |
| A color | `md-color-picker` | `<input type=color>` |
| Assign a subset from a bounded pool, side by side | `md-transfer-list` | two lists + buttons |
| Filter / attribute / removable entry | `md-chip` | small buttons |
| A date | `md-date-picker` | three selects |
| A time | `md-time-picker` | text field |

### 5.4 Navigation

| Need | Use | Don't use |
|---|---|---|
| Top-level destinations, mobile | `md-navigation-bar` + `md-navigation-tab` | tabs |
| Top-level destinations, desktop | `md-navigation-rail` + `md-navigation-rail-tab` | bottom bar |
| App header: title, actions, search | `md-app-bar` | a custom `<header>` |
| A dense action strip | `md-toolbar` | app bar |
| Sibling views **within** one screen | `md-tabs` + `md-tab` + `md-tab-panels` + `md-tab-panel` | navigation bar |
| Hierarchy / where-am-I | `md-breadcrumbs` + `md-breadcrumb-item` | text links |
| A linear multi-step flow | `md-stepper` + `md-step` | tabs |
| Contextual popup actions | `md-menu` + `md-menu-item`, `md-menu-item-group`, `md-sub-menu-item` | dialog |
| Hierarchical command menu (File → Export → PDF) | `md-menu` + `md-sub-menu-item` | nested dialogs |

### 5.5 Containment and feedback

| Need | Use | Don't use |
|---|---|---|
| Group related content | `md-card` | a bare `<div>` with a border |
| Blocking decision or focused task | `md-dialog` | a new page |
| Critical error the user must acknowledge | `md-dialog` | `md-snackbar` |
| Supplementary content from the bottom (mobile) | `md-bottom-sheet` | dialog |
| Supplementary content from the side (desktop) | `md-side-sheet` | dialog |
| Brief confirmation of an action, optionally undoable | `md-snackbar` | dialog, alert |
| Explain a control on hover/focus | `md-tooltip` | a dialog or inline hint |
| Progressive disclosure of sections | `md-accordion` + `md-accordion-item` | tabs |
| Visual separation | `md-divider` | a styled `<hr>` |
| A vertical set of records | `md-list` + `md-list-item` | a table |
| Determinate/indeterminate progress | `md-progress-indicator` | spinner GIF |
| Brand-consistent page/content loading | `md-loading-indicator` | custom spinner |
| Content-shaped loading placeholder | `md-skeleton` | a spinner over the whole page |
| Count or status on an element | `md-badge` | superscript text |
| Compact status dot | `md-status-dot` | a colored emoji |
| Read-only value within a known range (quota, battery) | `md-meter` | `md-progress-indicator` |
| A person or entity image/initials | `md-avatar` | a raw `<img>` |
| Touch feedback inside a custom control | `md-ripple` | custom CSS animation |

### 5.6 Data

| Need | Use | Don't use |
|---|---|---|
| Any table | `md-table-container` wrapping `md-table`, with `-head`/`-body`/`-row`/`-cell`/`-foot` inside the table and `-toolbar`/`-pagination` beside it in the container (§7.1) | a native `<table>` |
| Sorting, selection, paging on that table | the same parts — `md-table` carries the STATE (`sort-by`, `sort-order`, `selection`, `row-offset`, `row-count`, `loading`) and emits events; you own the data and do the actual sorting/paging | expecting it to sort an array for you |
| Hierarchy / reporting lines | `md-organization-chart` | nested lists |
| Compare categories | `md-bar-chart` | pie chart |
| Trend over time | `md-line-chart` | bar chart |
| Trend with cumulative volume | `md-area-chart` | line chart |
| Parts of a whole (≤ ~6 slices) | `md-pie-chart` | bar chart |
| Inline micro-trend in a cell or card | `md-sparkline` | a full chart |

> **There is no data-driven table component.** `md-table` is composable: you
> render the rows. It tracks and announces sort, selection and pagination state
> and emits events when the user changes them, but the sorting, filtering and
> slicing of your data is yours to perform. Render rows from your own array in
> response to those events.

### 5.7 Choosing the variant

The matrix picks the component; this picks its shape. Every value below is a
real enum member — anything not listed here is not a valid value.

| Component | Prop | Values, and when |
|---|---|---|
| `md-button` | `variant` | `filled` the one primary action · `tonal` a strong secondary · `outlined` secondary, and the safe choice for a destructive action behind a confirm · `text` low emphasis, dialog Cancel · `elevated` when it sits on a busy or coloured background (default `filled`) |
| `md-button` / `md-icon-button` / `md-button-group` | `size` | `xs` `sm` `md` `lg` `xl` — default `sm`; go `md`/`lg` for consumer CTAs, `xs`/`sm` for dense admin UI |
| `md-icon-button` | `variant` | `standard` (default) · `filled` · `tonal` · `outlined` |
| `md-button-group` | `variant` | `standard` spaced · `connected` fused into one bar |
| `md-fab` | `size` | `standard` (default) · `medium` · `large` |
| `md-fab` | `variant` | `primary-container` (default) · `secondary-container` · `tertiary-container` · `surface` · `primary` · `secondary` · `tertiary` |
| `md-card` | `variant` | `filled` for a group of comparable items · `elevated` (default) for a hero or featured item · `outlined` for a settings or form section |
| `md-text-field` / `md-select` | `variant` | `outlined` for forms on a surface · `filled` for dense or tinted layouts (`md-text-field` defaults to `filled`, `md-select` to `outlined`) — pick one and use it for every field on the screen |
| `md-text-field` | `type` | any native input type: `password`, `email`, `tel`, `url`, `search`, … (default `text`) |
| `md-text-field` | `multiline` | `"auto-grow"` grows with content · `"fixed"` with `rows` for a fixed comment box · `false` (default) single line |
| `md-search` | `variant` | `contained` (default) · `divided` |
| `md-app-bar` | `variant` | `small` (default) · `medium` · `large` for a prominent headline · `search` for a bar that hosts a field |
| `md-chip` | `variant` | `assist` (default) · `filter` for toggleable facets · `input` for user-entered removable values · `suggestion` |
| `md-chip` | `appearance` | `outlined` (default) · `filled` · `elevated` |
| `md-badge` | `variant` | `small` a bare dot · `large` (default) a count |
| `md-tooltip` | `variant` | `plain` (default) a short label on an icon control · `rich` an explanatory popover that may hold a link or action |
| `md-divider` | — | **no `variant`** — use the booleans `inset`, `inset-start`, `inset-end` |
| `md-side-sheet` | `variant` | `standard` coexists with page content · `modal` overlays with a scrim |
| `md-bottom-sheet` | `variant` | `standard` (default) · `detached` floating above the edge |
| `md-dialog` | `fullscreen` | boolean — a full-screen dialog for a long mobile task |
| `md-date-picker` | `variant` | `modal-input` (default) calendar plus a typed field · `modal` calendar only · `docked` inline, anchored to the field |
| `md-time-picker` | `variant` | `dial` · `input` (default) |
| `md-progress-indicator` | `variant` | `linear` (default) · `circular`; add `indeterminate` when the total is unknown |
| `md-list-item` | `lines` | `1` · `2` · `3` — must match how much supporting text you pass |
| `md-navigation-bar` | — | 3–5 destinations. Fewer than three: use `md-tabs`. More than five: a rail or a menu |
| `md-navigation-rail` | — | 3–7 destinations; cap the overflow with `max-visible` |

### 5.8 Not in the library

Rich text editor · file upload/dropzone · calendar/scheduler view · map ·
toast stack manager (use `md-snackbar` and manage the queue yourself) ·
data grid with virtualized columns. If the user needs one, say so plainly and
integrate a third-party component styled with the MD3 tokens.

**There is no `md-grid`, no `md-data-table`, no `md-layout`, no `md-icon`.**
If a tag is not listed in §6, it does not exist — do not emit it.

---

## §6 — Component inventory

**Every component has exactly one manual, and it is the readme.md in its own
source folder:**

```
./packages/core/src/components/<tag>/readme.md
```

e.g. [`md-select`](./packages/core/src/components/md-select/readme.md),
[`md-button`](./packages/core/src/components/md-button/readme.md).

**Load that file before you use the component.** There is no second, shorter
summary to rely on — this readme is the single source, so anything you do not
read there, you do not know. Each one carries When-to-use, a Do/Don't table
from M3, copy-paste patterns, an anti-patterns table, and the theming surface.

Work through them one at a time: pick the component from the decision matrix
(§5), load its readme, write that component's markup, then move to the next.

There are 81 manuals for 57 components: 24 of them document sub-components that
are only valid inside a parent (a table cell, a tab panel, a select option).
Every sub-component manual names its parent in the first line, and §7 below
summarises the nesting.

`status` in each manual's `llm:meta` block is one of:

- **`md3-mapped`** — has a Material Design 3 guidelines page; the Do/Don't is
  sourced from it.
- **`custom`** — an addition to MD3; guidance is derived house rules.
- **`sub-component`** — only valid inside a specific parent.

| Category | Components |
|---|---|
| Actions | `md-button` `md-icon-button` `md-fab` `md-fab-menu` `md-fab-menu-item` `md-split-button` `md-button-group` `md-segmented-button` `md-segmented-button-set` |
| Text input | `md-text-field` `md-number-field` `md-otp-field` `md-autocomplete` `md-search` |
| Selection | `md-select` `md-select-option` `md-multi-select` `md-checkbox` `md-radio` `md-switch` `md-slider` `md-rating` `md-color-picker` `md-transfer-list` `md-chip` |
| Pickers | `md-date-picker` `md-time-picker` |
| Navigation | `md-app-bar` `md-toolbar` `md-navigation-bar` `md-navigation-tab` `md-navigation-rail` `md-navigation-rail-tab` `md-tabs` `md-tab` `md-tab-panels` `md-tab-panel` `md-breadcrumbs` `md-breadcrumb-item` `md-menu` `md-menu-item` `md-menu-item-group` `md-sub-menu-item` `md-stepper` `md-step` |
| Containment | `md-card` `md-dialog` `md-bottom-sheet` `md-side-sheet` `md-snackbar` `md-tooltip` `md-accordion` `md-accordion-item` `md-divider` `md-list` `md-list-item` |
| Data | `md-table` `md-table-container` `md-table-head` `md-table-body` `md-table-row` `md-table-cell` `md-table-foot` `md-table-toolbar` `md-table-pagination` `md-table-sort-label` `md-table-expand-toggle` `md-organization-chart` |
| Charts | `md-bar-chart` `md-line-chart` `md-area-chart` `md-pie-chart` `md-sparkline` |
| Status & feedback | `md-progress-indicator` `md-loading-indicator` `md-skeleton` `md-badge` `md-status-dot` `md-meter` `md-avatar` `md-ripple` |

---

## §7 — Composition rules

### 7.1 What nests inside what

A sub-component is only valid inside its parent. Putting one anywhere else
produces an unstyled, unregistered-looking element with no keyboard behaviour,
because the parent is what wires roving tabindex, ARIA ids and selection.

| Parent | Children it manages |
|---|---|
| `md-button-group` | `md-button`, `md-icon-button` |
| `md-segmented-button-set` | `md-segmented-button` |
| `md-fab-menu` | `md-fab-menu-item` (anchored to an `md-fab` via `anchor="<id>"`) |
| `md-menu` | `md-menu-item`, `md-sub-menu-item`, `md-menu-item-group` — **not** `md-divider`; separate rows with `md-menu-item`'s own `divider` (or `gap`) prop |
| `md-menu-item-group` | `md-menu-item` |
| `md-sub-menu-item` | a nested `md-menu` in `slot="submenu"` — the items go in *that* menu. There is no default slot, so anything else you nest renders nothing |
| `md-select`, `md-multi-select`, `md-autocomplete` | `md-select-option` |
| `md-list` | `md-list-item`, `md-divider` |
| `md-tabs` | `md-tab` |
| `md-tab-panels` | `md-tab-panel` (one per tab, in tab order) |
| `md-navigation-bar` | `md-navigation-tab` |
| `md-navigation-rail` | `md-navigation-rail-tab`, plus an `md-fab` in `slot="fab"` |
| `md-accordion` | `md-accordion-item` |
| `md-stepper` | `md-step` (horizontal steppers also take `slot="content"`) |
| `md-breadcrumbs` | `md-breadcrumb-item` |
| `md-table-container` | `md-table` — **it wraps the table, not the other way round** — plus `md-table-toolbar` in `slot="top"` and `md-table-pagination` in `slot="bottom"`, which sit outside the scroll region |
| `md-table` | `md-table-head`, `md-table-body`, `md-table-foot` (and bare `md-table-row`). It does **not** accept the container, toolbar or pagination |
| `md-table-head` / `-body` / `-foot` | `md-table-row` |
| `md-table-row` | `md-table-cell`, plus `md-table-expand-toggle` for an expandable row |
| `md-table-cell` | `md-table-sort-label` in a header cell |
| `md-tooltip` | **its trigger** — the tooltip wraps the element it describes in its default slot |
| `md-dialog` | body content in the default slot; `md-button` in `slot="actions"` |
| `md-bottom-sheet` / `md-side-sheet` | content in the default slot; `md-button` in `slot="actions"`; headline in `slot="headline"` |
| `md-app-bar` | `md-icon-button` in `slot="leading"` and `slot="trailing"`; `md-menu` for overflow; a field in `slot="search"` on `variant="search"` |
| `md-toolbar` | `md-icon-button`, `md-button`, `md-button-group`; an `md-fab` in `slot="fab"`; `slot="leading"` / `slot="trailing"` for the end clusters |

### 7.2 Pairs that belong together

These don't nest — they sit next to each other in a working flow. Reaching for
one usually means you want the other.

| This | Goes with | Why |
|---|---|---|
| `md-icon-button` | `md-tooltip` | The tooltip supplies the visible meaning the icon lacks |
| `md-button` (`soft-disabled`) | `md-tooltip` | Explains *why* the action is unavailable |
| `md-fab` | `md-fab-menu` | The FAB is the menu's anchor |
| `md-split-button` | `md-menu` | The trailing half opens it |
| `md-card` | `md-button`, `md-icon-button`, `md-divider` | Footer actions, corner action, internal sections |
| `md-list-item` | `md-checkbox`, `md-switch`, `md-icon-button` | Trailing controls in a selectable or settings row |
| `md-bottom-sheet` / `md-side-sheet` | `md-list` | Action menus and filter panels inside the sheet |
| `md-search` | `md-list`, `md-avatar`, `md-icon-button` | Results in the panel; account and voice/filter affordances in the trailing slot |
| `md-date-picker` | `md-time-picker` | Date + time row for booking and scheduling forms |
| `md-time-picker` | `md-button` | The trigger, when `hide-trigger` is set. The picker **is** its own dialog — don't nest it in another one |
| `md-text-field` | `md-button` | Submit / cancel in the form footer |
| `md-multi-select` / `md-autocomplete` | `md-text-field`, `md-menu`, `md-chip` | The field is the trigger (and inherits its variant, density and error state), the menu is the option surface, chips are the selected values |
| `md-autocomplete` | `md-progress-indicator` | The loading row while suggestions are fetched |
| `md-transfer-list` | `md-checkbox`, `md-text-field`, `md-icon-button` | Per-row select, per-side search, mover controls |
| `md-number-field` | `md-text-field` hooks, `md-icon-button` | It *is* an `md-text-field` internally — every `--md-text-field-*` custom property passes through — and its steppers are `md-icon-button`s |
| `md-otp-field` | `md-button` | Verify action (`auto-submit` covers the no-button flow) |
| Any chart | `md-card` | Charts belong on a dashboard tile |
| `md-line-chart` | `md-segmented-button-set` | Period picker (1W / 1M / 1Y) driving the range |
| `md-sparkline` | `md-list-item`, `md-table-cell` | Trend column beside a value |
| `md-skeleton` | `md-card`, `md-list` | Render N placeholders in the real layout while fetching |
| `md-meter` | `md-chip`, `md-card` | Same semantic status colour on both; quota and usage summaries live on a card |
| `md-color-picker` | `md-text-field`, `md-button` | Label and helper text beside it in a form; save / cancel in the surrounding popover or dialog |
| `md-rating` | `md-text-field`, `md-card` | A rating row in a review form; aggregate scores on a review card |
| `md-accordion` | `md-divider` | Optional inner dividers inside long item content |
| `md-stepper` | `md-button` | Next / back / submit adjacent to the stepper |

### 7.3 Nesting that is always wrong

- A dialog opened from inside a dialog. Use `md-stepper` inside **one**
  `md-dialog`.
- A component inside a native interactive element (`<button>`, `<a>`) — it
  nests interactive controls and destroys the accessibility tree. Use the
  component's own `href` / `type` props.
- `md-tabs` used for top-level app navigation. Tabs switch sibling views of the
  same data; destinations are `md-navigation-bar` / `md-navigation-rail`.

---

## §8 — Page recipes

Complete, runnable screens. Each renders as-is once the components are
registered and the token sheet and font links from §3 are loaded — no
placeholder identifiers, no helper functions to write.

### 8.1 Login screen

`<form>` is load-bearing: it is what makes `required` block submit and what
`type="submit"` calls `requestSubmit()` on.

```html
<main style="display: grid; place-items: center; min-block-size: 100dvh; padding: 24px;">
  <form id="login-form" style="inline-size: min(420px, 100%);">
    <md-card variant="elevated" style="padding: 32px; display: flex; flex-direction: column; gap: 20px;">
      <h1 style="margin: 0; font: var(--md-sys-typescale-headline-medium-font);">Sign in</h1>

      <md-text-field
        variant="outlined"
        label="Email"
        type="email"
        name="email"
        autocomplete="username"
        required
      ></md-text-field>

      <md-text-field
        variant="outlined"
        label="Password"
        type="password"
        name="password"
        autocomplete="current-password"
        password-toggle="internal"
        required
      ></md-text-field>

      <md-button variant="filled" type="submit" full-width>Sign in</md-button>
      <md-button variant="text" href="/forgot-password">Forgot password?</md-button>
    </md-card>
  </form>
</main>

<script type="module">
  document.getElementById('login-form').addEventListener('submit', (e) => {
    e.preventDefault();
    const data = new FormData(e.currentTarget);
    console.log(data.get('email'), data.get('password'));
  });
</script>
```

### 8.2 Settings page (mobile)

Top app bar + grouped rows of instant-apply switches. `md-switch` uses
**`selected`**, not `checked`. The rows are `type="text"` (non-interactive), so
the switch is the only control — one tab stop per setting.

```html
<md-app-bar variant="small" headline="Settings">
  <md-icon-button slot="leading" icon="arrow_back" aria-label="Back"></md-icon-button>
</md-app-bar>

<main style="padding: 16px; display: flex; flex-direction: column; gap: 16px;">
  <md-card variant="outlined">
    <md-list>
      <md-list-item headline="Notifications" supporting-text="Push, email, in-app" lines="2">
        <md-switch slot="trailing" selected aria-label="Enable notifications" data-setting="notifications"></md-switch>
      </md-list-item>
      <md-divider></md-divider>
      <md-list-item headline="Dark mode" supporting-text="Match system" lines="2">
        <md-switch slot="trailing" aria-label="Enable dark mode" data-setting="dark"></md-switch>
      </md-list-item>
      <md-divider></md-divider>
      <md-list-item headline="Sync over cellular">
        <md-switch slot="trailing" selected aria-label="Sync over cellular" data-setting="cellular"></md-switch>
      </md-list-item>
    </md-list>
  </md-card>
</main>

<md-snackbar id="settings-toast" message="Setting saved"></md-snackbar>

<script type="module">
  const toast = document.getElementById('settings-toast');
  document.querySelectorAll('md-switch[data-setting]').forEach((sw) => {
    sw.addEventListener('mdChange', (e) => {
      if (sw.dataset.setting === 'dark') {
        document.documentElement.setAttribute('data-theme', e.detail.selected ? 'dark' : 'light');
      }
      toast.show();
    });
  });
</script>
```

### 8.3 Settings form (deferred save, with validation)

When settings are saved on submit rather than applied instantly, use a real
form. `required` blocks the submit; every control needs a `name` to reach
`FormData`.

```html
<form id="profile-form" style="max-inline-size: 560px; margin: 24px auto; padding: 0 16px;">
  <md-card variant="outlined" style="padding: 24px; display: flex; flex-direction: column; gap: 20px;">
    <h2 style="margin: 0; font: var(--md-sys-typescale-title-large-font);">Profile</h2>

    <md-text-field
      variant="outlined"
      label="Display name"
      name="displayName"
      required
      supporting-text="Shown on your public profile"
    ></md-text-field>

    <md-select variant="outlined" label="Language" name="language" value="en" required>
      <md-select-option value="en" label="English"></md-select-option>
      <md-select-option value="de" label="Deutsch"></md-select-option>
      <md-select-option value="ar" label="العربية"></md-select-option>
    </md-select>

    <!-- md-checkbox has NO label slot. It is a labelable, form-associated
         element: wrap it in a native <label> (which names it AND forwards
         clicks), or give the host an aria-label. Text between the tags is
         NOT rendered. -->
    <label style="display: inline-flex; align-items: center; gap: 12px; cursor: pointer;">
      <md-checkbox name="newsletter" value="yes" supporting-text="Monthly, no more"></md-checkbox>
      <span>Send me product news</span>
    </label>

    <div style="display: flex; gap: 8px; justify-content: flex-end;">
      <md-button variant="text" type="reset">Reset</md-button>
      <md-button variant="filled" type="submit">Save changes</md-button>
    </div>
  </md-card>
</form>

<md-snackbar id="saved-toast" message="Changes saved" action="Undo"></md-snackbar>

<script type="module">
  const form = document.getElementById('profile-form');
  const toast = document.getElementById('saved-toast');

  form.addEventListener('submit', (e) => {
    e.preventDefault();
    const data = Object.fromEntries(new FormData(form));
    console.log(data); // { displayName, language, newsletter? }
    toast.show();
  });

  toast.addEventListener('mdAction', () => form.reset());
</script>
```

### 8.4 Dashboard with a FAB

```html
<md-app-bar variant="medium" headline="Inbox">
  <md-icon-button slot="trailing" icon="search" aria-label="Search"></md-icon-button>
  <md-icon-button slot="trailing" icon="filter_list" aria-label="Filter"></md-icon-button>
</md-app-bar>

<main style="padding: 16px; display: grid; gap: 12px; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));">
  <md-card variant="filled" interactive style="padding: 16px;">
    <strong>Acme contract</strong>
    <p style="margin: 4px 0 0; color: var(--md-sys-color-on-surface-variant);">Renewal due in 5 days</p>
  </md-card>
  <md-card variant="filled" interactive style="padding: 16px;">
    <strong>Q4 report draft</strong>
    <p style="margin: 4px 0 0; color: var(--md-sys-color-on-surface-variant);">Shared by Alex</p>
  </md-card>
</main>

<md-fab
  icon="add"
  aria-label="New item"
  style="position: fixed; inset-block-end: 16px; inset-inline-end: 16px; z-index: var(--md-sys-z-index-navigation);"
></md-fab>
```

`inset-inline-end` (not `right`) is what keeps the FAB in the correct corner
under `dir="rtl"`.

### 8.5 Destructive confirmation dialog

`md-dialog` traps focus and returns it to the trigger on close — do not add your
own focus management. The error colouring goes through the button's own custom
properties, never a hex.

```html
<md-button id="open-delete" variant="outlined">Delete account</md-button>

<md-dialog id="confirm-delete" headline="Delete account?" icon="warning">
  <p style="margin: 0;">
    This will permanently delete your account and all associated data.
    This action cannot be undone.
  </p>
  <md-button id="cancel-delete" slot="actions" variant="text">Cancel</md-button>
  <md-button
    id="do-delete"
    slot="actions"
    variant="filled"
    style="--md-button-container-color: var(--md-sys-color-error);
           --md-button-label-color: var(--md-sys-color-on-error);"
  >Delete</md-button>
</md-dialog>

<script type="module">
  const dialog = document.getElementById('confirm-delete');
  document.getElementById('open-delete').addEventListener('mdClick', () => dialog.show());
  document.getElementById('cancel-delete').addEventListener('mdClick', () => dialog.close());
  document.getElementById('do-delete').addEventListener('mdClick', () => {
    dialog.close();
    // perform the deletion
  });
</script>
```

If you omit `slot="actions"` entirely, `md-dialog` renders its own Cancel / OK
pair (labels via `cancel-label` / `ok-label`) and closes itself.

### 8.6 Tabbed content page

`md-tab-panels` finds the nearest preceding `md-tabs` (or the one named by
`for`), follows its `mdTabChange`, and wires `aria-controls` /
`aria-labelledby` both ways. **No JavaScript is required**, and `md-tab` has no
`value` or `selected` prop — selection lives on `md-tabs` as `active-tab-index`.

```html
<md-tabs id="profile-tabs" aria-label="Profile sections" active-tab-index="0">
  <md-tab label="Posts"></md-tab>
  <md-tab label="Replies"></md-tab>
  <md-tab label="Likes" badge="3"></md-tab>
</md-tabs>

<md-tab-panels for="profile-tabs">
  <md-tab-panel style="padding: 16px;">
    <p style="margin: 0;">Your posts appear here.</p>
  </md-tab-panel>
  <md-tab-panel style="padding: 16px;">
    <p style="margin: 0;">Your replies appear here.</p>
  </md-tab-panel>
  <md-tab-panel style="padding: 16px;">
    <p style="margin: 0;">Posts you liked appear here.</p>
  </md-tab-panel>
</md-tab-panels>
```

To react to the switch (lazy-loading a panel, for example), listen on the tabs:

```js
document.getElementById('profile-tabs')
  .addEventListener('mdTabChange', (e) => console.log(e.detail.index, e.detail.previousIndex));
```

### 8.7 The full recipe library

Twenty-two more complete screens live in the documentation, each with a live
demo, the full markup, framework tabs, and production notes. When the user's
request matches one of these, read that page (append the slug to
`https://awc-ui.dev/recipes/`) instead of composing from scratch:

| Recipe slug | Screen |
|---|---|
| `two-factor-verification` | OTP entry, resend countdown, backup-codes dialog |
| `kpi-overview` | Stat tiles with sparklines + charts under a range switcher |
| `data-grid-console` | Bulk-action data table: filters, selection, undo |
| `server-fleet-status` | Table of hosts with meters, sparklines, status dots |
| `release-health-drilldown` | Table row → side-sheet master-detail with charts |
| `csv-import-wizard` | Stepper: upload, map columns, validate, import |
| `role-permission-assignment` | Transfer-list permissions with confirm dialog |
| `org-chart-explorer` | Searchable org chart with side-sheet profiles |
| `moderation-queue` | Verdict controls, confidence meter, card queue |
| `checkout-wizard` | Three-step commerce checkout with validation |
| `appointment-booking` | Date + time pickers inside a stepper flow |
| `survey-nps` | Paged survey using every input control |
| `notification-preferences` | Accordion × switch matrix, quiet hours |
| `app-shell` | Responsive rail/bar chrome, SSR-ready, zero CLS |
| `inbox-shell` | Three-zone list + reading-pane layout |
| `mobile-filter-sheet` | Bottom-sheet filters with applied-chip row |
| `product-reviews` | Rating input + per-star meter breakdown |
| `order-tracking` | Shipment timeline stepper with progress meter |
| `portfolio-markets` | Finance charts + holdings table + trade ticket |
| `pricing-page` | Plan cards, billing toggle, comparison table |
| `async-feedback-patterns` | Skeleton/progress/snackbar choreography rules |
| `charts-gallery` | Every chart component, live-retheming palette |

---

## §9 — Universal do's and don'ts

Apply to every component. Component-specific rules live in each manual.

### 9.1 API and styling

| ✅ Do | ❌ Don't |
|---|---|
| Use the custom element directly — it *is* the control, with its own `href` / `type` props | Wrap it in a native `<button>` / `<a>` (§7.3) |
| Set arrays and objects as **JS properties** (`el.items = [...]`) | Pass them as HTML attributes — they won't parse |
| Theme via `--md-<component>-*` properties, then `::part()` | Reach into shadow internals or override `.md-*` classes |
| Change appearance through design tokens (§4.1) | Hardcode hex colors, px spacing, shadows, or font stacks |
| Use `--md-sys-z-index-*` for your own overlays | Invent z-indexes that land under a menu |
| Use logical CSS (`margin-inline-start`, `inset-inline-end`) | Use `margin-left`, `right`, `padding-right` |
| Set `data-density` / `data-theme` / `dir` once, globally | Set them per component unless you mean a local exception |
| Listen to the component's `md*` events | Rely on native `click` — it fires even when the component's `disabled` / `loading` guard suppressed the action |
| Check the manual for the state prop name | Assume `checked`; `md-switch` uses `selected` |
| Render the element, then call its `@Method` | Call `.show()` on an element not yet in the DOM |

Toggling components flip their own state on activation and *then* emit. On
`md-button`, `mdClick` is cancelable — `preventDefault()` on it vetoes the
toggle and any navigation. `mdChange` fires after the flip and is not
cancelable. If a controlled parent rejects a change it must revert the child
explicitly.

`md-button` has a **toggle mode**: set `toggle` and the button flips its own
`selected` on each activation and exposes `aria-pressed`. `selected` is the
state, not the switch — set it for the initial pressed state and read it back
from `mdClick`'s `detail.selected`. Setting `toggle` and then styling
"pressed" yourself, or setting `selected` without `toggle` (which emits no
`aria-pressed` at all), both produce a control that lies to assistive tech.

### 9.2 Content and hierarchy

| ✅ Do | ❌ Don't |
|---|---|
| Use sentence case for all labels | Uppercase or title-case UI text |
| Keep one high-emphasis action per screen region | Compete `filled` buttons against each other |
| Use `soft-disabled` + `md-tooltip` for contextually-unavailable actions | Use `disabled` and remove it from tab order with no explanation |
| Localize every text prop and `aria-label` | Leave default English prop values in a translated app |

**`disabled` vs `soft-disabled`.** Both render the disabled appearance, but
`disabled` also removes the control from the tab order, so a keyboard or screen
reader user can never find out *why* it is off. `soft-disabled` keeps the
control focusable and announced while still blocking activation — which is what
lets an `md-tooltip` on it explain the gate. Use it whenever the reason is
informative rather than obvious.

Nesting rules — dialog inside a dialog, a component inside a native
`<button>` / `<a>`, tabs used as app navigation — live in §7.3.

### 9.3 Accessibility contract

The library ships WCAG 2.1 AA keyboard and ARIA wiring by default. These are the
rules you must not break:

1. **Every icon-only control gets an accessible name.** `md-icon-button`,
   `md-fab`, and icon-only `md-tab` are nameless without `aria-label` (or
   `aria-labelledby`). `md-fab` will also accept `label`, and warns in the
   console when it has neither.
2. **Every form field gets a `label` prop.** `placeholder` is not a label — it
   disappears on type.
3. **Don't break the tab order.** Every interactive control must be reachable by
   Tab and operable by Enter/Space. If you add `tabindex="-1"` to anything,
   have a reason.
4. **Don't write your own focus trap.** `md-dialog`, `md-bottom-sheet` and
   `md-side-sheet` trap focus while open and restore it to the trigger on
   close — including across shadow boundaries. Adding your own fights theirs.
5. **Don't wrap components in your own live regions.** `md-snackbar` announces
   itself (`politeness="polite"` by default, `"assertive"` when the message must
   interrupt). For an error that blocks the task, use `md-dialog`.
6. **Don't disable motion yourself.** Components honour
   `prefers-reduced-motion: reduce` internally.
7. **Directional icons do not auto-flip in RTL** — see §4.5.
8. **Re-verify contrast after overriding any colour role** — the library's AA
   testing covers the shipped palette only. The Theme Generator at
   <https://awc-ui.dev/theme-generator> runs the WCAG checks live (§4.2).

---

## §10 — Before you ship

1. **Every icon-only control has an accessible name.**
2. **Keyboard-only pass**: reach and operate every control; focus is always
   visible; no traps in dialogs/menus/sheets; focus returns to the trigger.
3. **Theme pass**: light *and* dark, if both are supported — and the attribute
   is set before first paint.
4. **RTL pass**, if an RTL locale ships — check directional icons specifically,
   and grep your own CSS for physical properties.
5. **Density pass** at the configured rung — no clipped labels, touch targets
   still adequate. Remember `density="0"` is inert; use
   `--md-sys-density-scale: 0` to opt a subtree out.
6. **Forms**: every control has a `name`; `required` blocks submit; `FormData`
   contains every field; reset works.
7. **No hardcoded strings** left in markup if the app is localized — including
   default prop values like `Search`, `Dismiss`, `No results`.
8. **No hardcoded design values** — grep the diff for hex colours, `px` radii,
   `box-shadow`, and `z-index` literals.
9. **Contrast** re-verified against AA if colour roles were overridden.
10. **SSR**: if server-rendered, confirm no hydration mismatch and that content
    is present with JS disabled.
11. **No shadow-internal CSS** — only tokens, custom properties, and `::part()`.
12. **Every `md-*` tag you emitted appears in §6.** If it doesn't, it doesn't
    exist.