svelte-kit-vice/web/routes/uix/components/section/+page.svelte

<script lang="ts">
	import { Section, type SectionProps, type SectionSize } from '$uix/eidos/components/section';
	import { Box } from '$uix/eidos/components/box';
	import { compileMorfo } from '$uix/morfo';
	import { sectionMorfo } from '@/uix/morfo/components/section';
	import TokensPanel from '../../lib/TokensPanel.svelte';

	type Tab = 'live' | 'api' | 'morfo' | 'sema' | 'recipe' | 'tokens'
		| 'a11y';
	type TraceEntry = { event: string; family: string; intent?: string; at: number };
	let tab = $state<Tab>('live');
	let trace = $state<TraceEntry[]>([]);
	let stageRef = $state<HTMLElement | null>(null);

	// ── Live state — Section props ────────────────────────────────────────
	let size = $state<SectionSize>('md');
	let paddingY = $state<string>('');
	let paddingX = $state<number>(4);

	const sizeOptions: readonly SectionSize[] = ['sm', 'md', 'lg', 'xl'];

	const sectionProps = $derived<Partial<SectionProps>>({
		size,
		paddingY: paddingY || undefined,
		paddingX
	});

	// ── Compiled morfo ────────────────────────────────────────────────────
	const compiled = compileMorfo(sectionMorfo);
	const partsList = $derived([...compiled.parts.byKebab.values()]);
	const events = $derived([...compiled.actions.byName.values()]);

	$effect(() => {
		const el = stageRef;
		if (!el) return;
		const obs = new MutationObserver((mutations) => {
			for (const m of mutations) {
				if (m.attributeName !== 'data-event') continue;
				const target = m.target as Element;
				const ev = target.getAttribute('data-event');
				if (!ev) continue;
				trace = [
					{
						event: ev,
						family: target.getAttribute('data-event-family') ?? '—',
						intent: target.getAttribute('data-event-intent') ?? undefined,
						at: Date.now()
					},
					...trace
				].slice(0, 6);
			}
		});
		obs.observe(el, { attributes: true, subtree: true, attributeFilter: ['data-event'] });
		return () => obs.disconnect();
	});

	// ── Code snippet ──────────────────────────────────────────────────────
	const eidosSnippet = $derived(
		[
			"<script lang='ts'>",
			"  import { Section } from '$uix/eidos/components/section';",
			'</' + 'script>',
			'',
			'<Section',
			size !== 'lg' && `  size="${size}"`,
			paddingY && `  paddingY="${paddingY}"`,
			paddingX > 0 && `  paddingX={${paddingX}}`,
			'>',
			'  …',
			'</Section>'
		]
			.filter(Boolean)
			.join('\n')
	);
</script>

<div data-uix-canvas-inner>
	<header>
		<div data-uix-eyebrow>Layout · Section</div>
		<h1 data-uix-page-title>Section</h1>
		<p data-uix-page-lede>
			Top-level page section with consistent block-axis padding. Four size tokens
			(<code>sm · md · lg · xl</code>) map to <code>--section-padding-block-{`{size}`}</code>.
			It renders a real <code>&lt;section&gt;</code>, and it is a page section entire:
			<code>containerSize</code> caps the measure and <code>decor</code> paints the
			decorative band, both optional, plus the <code>Section.Header</code> that names it.
			An unnamed <code>&lt;section&gt;</code> is not a landmark — pass
			<code>aria-label</code> (or <code>aria-labelledby</code>) and it becomes a
			<code>region</code>. For centred max-width content on its own use
			<a href="/uix/components/container">&lt;Container&gt;</a>; for non-semantic padding use
			<a href="/uix/components/box">&lt;Box&gt;</a>.
		</p>
		<div data-uix-page-meta>
			<span data-uix-meta-pill>
				<span data-uix-meta-key>parts</span>{compiled.parts.order.length}
			</span>
			<span data-uix-meta-pill>
				<span data-uix-meta-key>events</span>0
			</span>
			<span data-uix-meta-pill>
				<span data-uix-meta-key>sizes</span>{sizeOptions.length}
			</span>
			<span data-uix-meta-pill>
				<span data-uix-meta-key>scope</span>eidos
			</span>
		</div>
	</header>

	<!-- Live preview always rendered -->
	<div data-uix-stage>
		<div
			data-uix-stage-area
			bind:this={stageRef}
			style="background: repeating-linear-gradient(0deg, transparent 0 8px, var(--color-surface-2) 8px 9px); inline-size: 100%;"
		>
			<Section
				{...sectionProps}
				style="border: 1px dashed var(--color-border-default); border-radius: var(--radius-md); background: var(--color-surface-1);"
			>
				<Box
					padding={3}
					style="border: 1px solid var(--color-affirm-border); border-radius: var(--radius-sm); background: var(--color-affirm-track); color: var(--color-affirm-text); text-align: center;"
				>
					Content (padding-block: var(--section-padding-block-{size}))
				</Box>
			</Section>
		</div>
		<div data-uix-stage-trace>
			<span data-uix-stage-trace-key>trace</span>
			<span>{trace.length === 0 ? 'no semantic events' : `${trace.length} event(s)`}</span>
			<span style="color: var(--uix-text-faint)">·</span>
			<span data-uix-stage-trace-key>size</span>
			<span>{size}</span>
			<span style="margin-inline-start: auto;">
				<span data-uix-stage-trace-key>paddingY</span> {paddingY || `var(--section-padding-block-${size})`}
			</span>
		</div>
	</div>

	<div data-uix-tabs role="tablist">
		<button data-uix-tab data-active={tab === 'live'} onclick={() => (tab = 'live')}>Live</button>
		<button data-uix-tab data-active={tab === 'api'} onclick={() => (tab = 'api')}>
			API <span data-uix-tab-count>2</span>
		</button>
		<button data-uix-tab data-active={tab === 'morfo'} onclick={() => (tab = 'morfo')}>
			<span data-uix-layer-badge="morfo">morfo</span>
			<span data-uix-tab-count>{partsList.length}p · 0e</span>
		</button>
		<button data-uix-tab data-active={tab === 'sema'} onclick={() => (tab = 'sema')}>
			<span data-uix-layer-badge="sema">sema</span>
			<span data-uix-tab-count>{events.length}</span>
		</button>
		<button data-uix-tab data-active={tab === 'recipe'} onclick={() => (tab = 'recipe')}>Recipe</button>
		<button data-uix-tab data-active={tab === 'tokens'} onclick={() => (tab = 'tokens')}>
			Tokens <span data-uix-tab-count>4</span>
		</button>
		<button data-uix-tab data-active={tab === 'a11y'} onclick={() => (tab = 'a11y')}>A11y</button>
	</div>

	{#if tab === 'live'}
		<section data-uix-section>
			<h2 data-uix-section-title>Controls</h2>
			<p data-uix-section-desc>
				Section is eidos-native — no <span data-uix-layer-badge="soma">soma</span> split. The
				horizontal hatched background shows how the block padding shifts content vertically
				as <code>size</code> changes. Note the rendered element is a <code>&lt;div&gt;</code>
				— see the A11y tab for guidance on adding a real landmark.
			</p>

			<div data-uix-subsection-head>
				<span data-uix-layer-badge="eidos">eidos</span> props · padding
			</div>
			<div data-uix-controls>
				<label data-uix-control>
					<span data-uix-control-label>size <span data-uix-control-hint>→ var(--section-padding-block-N)</span></span>
					<span data-uix-chips role="radiogroup">
						{#each sizeOptions as opt}
							<button data-uix-chip data-active={size === opt} onclick={() => (size = opt)}
								>{opt}</button
							>
						{/each}
					</span>
				</label>
				<label data-uix-control>
					<span data-uix-control-label>paddingY <span data-uix-control-hint>override size-keyed default</span></span>
					<input
						type="text"
						placeholder="(size default)"
						bind:value={paddingY}
						style="inline-size: 12rem;"
					/>
				</label>
				<label data-uix-control>
					<span data-uix-control-label>paddingX <span data-uix-control-hint>inherited from Box</span></span>
					<input
						type="number"
						min="0"
						max="8"
						step="1"
						bind:value={paddingX}
						style="inline-size: 6rem;"
					/>
				</label>
			</div>

			<!-- ── Code snippet (eidos-native — no soma layer) ──────────────── -->
			<div data-uix-code>
				<div data-uix-code-head>
					<span data-uix-layer-badge="eidos">eidos</span>
					<span>visual · size-keyed block padding on top of Box</span>
					<span data-uix-code-lang>svelte</span>
				</div>
				<pre><code>{eidosSnippet}</code></pre>
			</div>
		</section>
	{/if}

	{#if tab === 'api'}
		<section data-uix-section>
			<h2 data-uix-section-title>API reference</h2>
			<p data-uix-section-desc>
				Section is a one-prop specialization of <a href="/uix/components/box"
					><code>&lt;Box&gt;</code></a
				>: it sets <code>width: 100%</code>, picks a default
				<code>padding-block</code> from <code>size</code>, and renders as
				<code>&lt;section&gt;</code> (Box's own <code>as</code>). If you pass
				<code>paddingY</code> directly, your value wins over the size-keyed default.
			</p>

			<div data-uix-subsection-head>Padding</div>
			<div data-uix-table-wrap>
				<table data-uix-table>
					<thead><tr><th>Prop</th><th>Type</th><th>Default</th><th>Notes</th></tr></thead>
					<tbody>
						<tr><td class="name">size</td><td class="type">sm | md | lg | xl</td><td class="default">'lg'</td><td>Maps to <code>--section-padding-block-{`{size}`}</code>: sm→8 / md→12 / lg→16 / xl→24 space steps.</td></tr>
						<tr><td class="name">paddingY</td><td class="type">number | string</td><td class="default">SIZE_TO_PADDING[size]</td><td>Override the size-keyed default per-instance.</td></tr>
					</tbody>
				</table>
			</div>

			<div data-uix-subsection-head>Inherited from Box</div>
			<p data-uix-section-desc>
				Every <a href="/uix/components/box">BoxProps</a> field is forwarded:
				<code>padding*</code>, <code>margin*</code>, <code>width</code> (locked to 100% by
				Section), <code>height</code>, <code>position</code>, <code>overflow*</code>. Pass
				<code>paddingX</code> for horizontal padding (no default).
			</p>

			<div data-uix-subsection-head>Measure, decoration and header</div>
			<p data-uix-section-desc>
				<code>containerSize</code> composes a <code>&lt;Container&gt;</code> INSIDE the
				section; omit it and the children render directly, exactly as before the prop
				existed. <code>decor</code> paints a <code>Background.Pattern</code> as a CHILD, so
				the band bleeds the full width behind the measure and no extra box is gained. And
				<code>Section.Header</code> is the section's name — a <code>Heading level=2</code>
				and usually a <code>Text</code>, capped to a measure and revealed on scroll. The
				three landed on 2026-08-19: sixteen blocks of the tier were re-wiring the same
				chassis by hand, and eight had copied the same header (one had already drifted).
			</p>

			<div data-uix-subsection-head>Reference comparison</div>
			<div data-uix-table-wrap>
				<table data-uix-table>
					<thead><tr><th>Library</th><th>Closest equivalent</th><th>Difference</th></tr></thead>
					<tbody>
						<tr><td class="name">radix-themes</td><td><code>&lt;Section&gt;</code></td><td>Radix renders a real <code>&lt;section&gt;</code> by default and takes <code>size="1..4"</code>; UIX uses named tokens (<code>sm..xl</code>) and also renders <code>&lt;section&gt;</code>, plus the measure, the decoration and the header.</td></tr>
						<tr><td class="name">chakra-ui</td><td>n/a</td><td>Chakra has no dedicated Section — they recommend <code>&lt;Box as="section" py="…"&gt;</code>. UIX names the pattern as a primitive for consistency.</td></tr>
						<tr><td class="name">mantine</td><td>n/a</td><td>Mantine has no Section either. Sections are usually authored ad-hoc with Stack + AppShell.</td></tr>
					</tbody>
				</table>
			</div>
		</section>
	{/if}

	{#if tab === 'morfo'}
		<section data-uix-section>
			<h2 data-uix-section-title>Morfo contract</h2>

			<div data-uix-table-wrap>
				<table data-uix-table>
					<thead><tr><th>Field</th><th>Value</th></tr></thead>
					<tbody>
						<tr><td class="name">name</td><td>{sectionMorfo.name}</td></tr>
						<tr><td class="name">kebab</td><td><code>{sectionMorfo.kebab}</code></td></tr>
						<tr><td class="name">scope</td><td>{sectionMorfo.scope.join(', ')}</td></tr>
						<tr><td class="name">parts</td><td>{partsList.length}</td></tr>
						<tr><td class="name">events</td><td>0</td></tr>
					</tbody>
				</table>
			</div>

			<div data-uix-subsection-head>Parts</div>
			<div data-uix-table-wrap>
				<table data-uix-table>
					<thead><tr><th>kebab</th><th>marker</th><th>element</th><th>archetype</th><th>optional</th></tr></thead>
					<tbody>
						{#each partsList as part}
							<tr>
								<td class="name">{part.kebab}</td>
								<td><code data-uix-part-marker>[{part.marker}]</code></td>
								<td class="type">&lt;{part.defaultElement}&gt;</td>
								<td class="type">{part.archetype}</td>
								<td class="default">{part.optional ? 'yes' : 'no'}</td>
							</tr>
						{/each}
					</tbody>
				</table>
			</div>

			<p data-uix-section-desc style="margin-top: var(--uix-space-4);">
				Section composes through <code>&lt;Box&gt;</code>, so the rendered DOM is a single
				<code>div[data-box][data-section]</code> shell with a <code>data-size</code>
				attribute. Recipe lives at
				<code>src/uix/eidos/components/section/section.css</code> and declares the
				<code>--section-padding-block-*</code> tokens locally.
			</p>
		</section>
	{/if}

	{#if tab === 'sema'}
		<section data-uix-section>
			<h2 data-uix-section-title>
				<span data-uix-layer-badge="sema">sema</span> · events
			</h2>
			<p data-uix-section-desc>
				Section declares no semantic events. As a passive layout primitive, it does not
				commit, emerge, or react to anything — it just pads its children. Content inside the
				section owns its own sema.
			</p>
		</section>
	{/if}

	{#if tab === 'tokens'}
		<TokensPanel component="section" stage={stageRef ?? undefined} />
	{/if}

	{#if tab === 'recipe'}
		<section data-uix-section>
			<h2 data-uix-section-title>Eidos recipe</h2>
			<p data-uix-section-desc>
				Recipe lives in <code>src/uix/eidos/components/section/section.css</code>. The
				<code>--section-padding-block-*</code> tokens are defined locally on the
				<code>[data-section]</code> selector (intentionally not in the foundation — Section
				is the sole consumer).
			</p>
			<div data-uix-table-wrap>
				<table data-uix-table>
					<thead><tr><th>Selector</th><th>Owner</th><th>Purpose</th></tr></thead>
					<tbody>
						<tr>
							<td class="name"><code>[data-section]</code></td>
							<td><span data-uix-tag data-kind="morfo">morfo</span></td>
							<td>Provider marker. Declares the per-size padding tokens and locks <code>inline-size: 100%</code>.</td>
						</tr>
					</tbody>
				</table>
			</div>
		</section>
	{/if}

	{#if tab === 'a11y'}
		<section data-uix-section>
			<h2 data-uix-section-title>Accessibility</h2>
			<div data-uix-table-wrap>
				<table data-uix-table>
					<thead><tr><th>Concern</th><th>Contract</th></tr></thead>
					<tbody>
						<tr><td class="name">Role</td><td>Section renders a real <code>&lt;section&gt;</code>. That is NOT a landmark on its own: a <code>&lt;section&gt;</code> is exposed as <code>region</code> only once it carries an accessible name, so an unnamed one is plain structure — which is the right default for a page that stacks many.</td></tr>
						<tr><td class="name">Label</td><td>Pass <code>aria-label</code>, or <code>aria-labelledby</code> pointing at the heading inside <code>Section.Header</code>. Naming it is what turns it into a findable <code>region</code>.</td></tr>
						<tr><td class="name">Keyboard</td><td>Section is not focusable. Tab order follows DOM order.</td></tr>
						<tr><td class="name">Reduced motion</td><td>Section does not animate.</td></tr>
					</tbody>
				</table>
			</div>
		</section>
	{/if}
</div>