feat(eidos): calendar month/year via popover+grid; nav controls compose system Button/IconButton

- Month/year choosers replace the native `<select>` with a NON-MODAL popover whose
  content is the reused `MonthGrid` / `YearGrid`. Stays non-modal so it also works
  opened inside the date-picker's own popover (no nested modal trap). The viewed
  month/year is highlighted with the selected style; `locale` is threaded and the
  month is capitalized so es ("ene") and en ("Jan") read consistently. `YearGrid`
  gains a `pageAligned` opt so the chooser can start on the selected year.
- Prev / Next compose the system `<IconButton>` (chevron glyph from the primitive);
  the month / year triggers compose the system `<Button>` via the Popover.Trigger
  `child` snippet. The bespoke border / bg / hover / focus / disabled chrome is
  removed from `calendar.css` — it all comes from the primitive now; the trigger
  label tracks the picker font (16px).
- The day grid is centered under the slightly wider header.
- The date-picker reuses these calendar parts, so it inherits all of the above.

WIP (parked, not composed anywhere): the soma `CalendarProvider` also carries an
unused `view` state + `Calendar.MonthView` / `YearView` / `HeadingTrigger` from an
in-place view-switch attempt. The popover approach above is the active one.

Excludes words/palabras/chronos.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/uix/eidos/components/calendar/calendar-heading-trigger.svelte

@@ -0,0 +1,28 @@
+<script lang="ts">
+	/**
+	 * Eidos `<Calendar.HeadingTrigger>` — the view-switch heading button. Opt-in
+	 * alternative to the static `<Calendar.Heading>`: wraps it in a button that,
+	 * on click, drills UP the navigation view (day → month → year), reusing the
+	 * `MonthGrid` / `YearGrid` rendered by `<Calendar.MonthView>` /
+	 * `<Calendar.YearView>`. Use it only when those views are composed.
+	 *
+	 * It nests the soma `<Calendar.Heading>` so the label, id registration and
+	 * `aria-labelledby` wiring for the grid keep working unchanged.
+	 */
+	import type { HTMLButtonAttributes } from 'svelte/elements';
+	import * as Calendar from '$soma/components/calendar';
+	import { CalendarProvider } from '$soma/components/calendar';
+
+	let { ...rest }: HTMLButtonAttributes = $props();
+
+	const provider = CalendarProvider.require();
+</script>
+
+<button
+	type="button"
+	data-calendar-heading-trigger
+	onclick={() => provider.advanceView()}
+	{...rest}
+>
+	<Calendar.Heading />
+</button>

src/uix/eidos/components/calendar/calendar-month-select.svelte

@@ -1,16 +1,64 @@
 <script lang="ts">
-	import * as Calendar from '$soma/components/calendar';
+	/**
-	import type { CalendarMonthSelectProps, CalendarMonthSelectSnippetProps } from './types';
+	 * Eidos `<Calendar.MonthSelect>` — month chooser. A NON-MODAL popover whose
+	 * trigger shows the current month + a chevron and whose content is the reused
+	 * `MonthGrid` (12 month cells). Picking a month sets the calendar month and
+	 * closes. Replaces the former native `<select>`; staying non-modal means it
+	 * also works opened inside the date-picker's own popover (no nested trap).
+	 *
+	 * No `value` is passed to the grid — a controlled value would make the grid
+	 * fire a select on mount and slam the popover shut as it opens.
+	 */
+	import { CalendarProvider } from '$soma/components/calendar';
+	import { ChevronDown } from '$uix/eidos/components/icon';
+	import { Button } from '$uix/eidos/components/button';
+	import Popover from '../popover';
+	import MonthGrid from '../month-grid';
+	import type { MonthValue, MonthGridProviderSnippetProps } from '$soma/components/month-grid';
 
-	let { children: bodyContent, ...rest }: CalendarMonthSelectProps = $props();
+	const provider = CalendarProvider.require();
+	let open = $state(false);
+
+	const placeholderYear = $derived(provider.opts.placeholder.current.year);
+	const placeholderMonth = $derived(provider.opts.placeholder.current.month);
+	// Abbreviated month (matches the grid) so the trigger stays compact and never
+	// grows the header.
+	const monthLabel = $derived(
+		new Intl.DateTimeFormat(provider.effectiveLocale, { month: 'short' }).format(
+			new Date(2000, placeholderMonth - 1, 1)
+		)
+	);
+	const placeholder = $derived<MonthValue>({ year: placeholderYear, month: placeholderMonth });
+	// Highlight the viewed month with the SELECTED style (filled), like the grid.
+	const value = $derived<MonthValue>({ year: placeholderYear, month: placeholderMonth });
+
+	function onValueChange(next: MonthValue | undefined): void {
+		if (!next) return;
+		provider.setMonth(next.month);
+		open = false;
+	}
 </script>
 
-{#if bodyContent}
+<Popover bind:open modal={false}>
-	<Calendar.MonthSelect {...rest}>
+	<Popover.Trigger data-calendar-month-select>
-		{#snippet children(snippetProps: CalendarMonthSelectSnippetProps)}
+		{#snippet child({ props }: { props: Record<string, unknown> })}
-			{@render bodyContent(snippetProps)}
+			<Button {...props} variant="ghost" size="sm">
+				<span data-calendar-select-label>{monthLabel}</span>
+				<ChevronDown data-calendar-select-chevron aria-hidden="true" />
+			</Button>
 		{/snippet}
-	</Calendar.MonthSelect>
+	</Popover.Trigger>
-{:else}
+	<Popover.Portal>
-	<Calendar.MonthSelect {...rest} />
+		<Popover.Content data-calendar-select-popover>
-{/if}
+			<MonthGrid {placeholder} {value} locale={provider.effectiveLocale} {onValueChange}>
+				{#snippet children({ months }: MonthGridProviderSnippetProps)}
+					<MonthGrid.Grid>
+						{#each months as month (month)}
+							<MonthGrid.Cell {month} />
+						{/each}
+					</MonthGrid.Grid>
+				{/snippet}
+			</MonthGrid>
+		</Popover.Content>
+	</Popover.Portal>
+</Popover>

src/uix/eidos/components/calendar/calendar-month-view.svelte

@@ -0,0 +1,60 @@
+<script lang="ts">
+	/**
+	 * Eidos `<Calendar.MonthView>` — the month grid shown when the calendar's
+	 * navigation view is `'month'` (Ark/Mantine/MUI in-place view-switch). Reuses
+	 * the eidos `<MonthGrid>`; picking a month sets the calendar's placeholder and
+	 * drills back DOWN to the day grid. The heading is a button that drills UP to
+	 * the year grid. Self-gates on `provider.view`.
+	 *
+	 * The grid drives a LOCAL navigation year (re-seeded from the calendar each
+	 * time this view activates) instead of syncing back into the calendar — that
+	 * decoupling is what avoids the placeholder feedback loop. No `value` is passed
+	 * so the grid never fires a spurious select on mount.
+	 */
+	import { CalendarProvider } from '$soma/components/calendar';
+	import MonthGrid from '../month-grid';
+	import type { MonthPlaceholder, MonthGridProviderSnippetProps } from '$soma/components/month-grid';
+	import type { MonthGridSize } from '../month-grid';
+
+	let { size = 'md' }: { size?: MonthGridSize } = $props();
+
+	const provider = CalendarProvider.require();
+
+	// Local navigation year — the grid's own prev/next-year browsing lives here,
+	// re-seeded from the calendar on each entry into the month view.
+	let navYear = $state(provider.opts.placeholder.current.year);
+	$effect(() => {
+		if (provider.view === 'month') navYear = provider.opts.placeholder.current.year;
+	});
+	const placeholder = $derived<MonthPlaceholder>({ year: navYear });
+
+	function onPlaceholderChange(next: MonthPlaceholder): void {
+		navYear = next.year;
+	}
+	function onValueChange(next: { year: number; month: number } | undefined): void {
+		if (next) provider.selectMonthView(next.year, next.month);
+	}
+</script>
+
+{#if provider.view === 'month'}
+	<MonthGrid {size} {placeholder} {onPlaceholderChange} {onValueChange}>
+		{#snippet children({ months }: MonthGridProviderSnippetProps)}
+			<MonthGrid.Header>
+				<MonthGrid.PrevButton>‹</MonthGrid.PrevButton>
+				<button
+					type="button"
+					data-calendar-view-heading
+					onclick={() => provider.setView('year')}
+				>
+					{navYear}
+				</button>
+				<MonthGrid.NextButton>›</MonthGrid.NextButton>
+			</MonthGrid.Header>
+			<MonthGrid.Grid>
+				{#each months as month (month)}
+					<MonthGrid.Cell {month} />
+				{/each}
+			</MonthGrid.Grid>
+		{/snippet}
+	</MonthGrid>
+{/if}

src/uix/eidos/components/calendar/calendar-next-button.svelte

@@ -1,10 +1,30 @@
 <script lang="ts">
+	/**
+	 * Eidos `Calendar.NextButton` — composes the system `<IconButton>` (which itself
+	 * composes `<Button>`) via soma's `child` snippet, instead of styling a bespoke
+	 * native `<button>`. The forward-chevron glyph plus sizing / hover / focus /
+	 * disabled / a11y all come from the primitive — no duplicated chrome.
+	 */
+	import { ActiveEidos } from '$uix/eidos';
 	import * as Calendar from '$soma/components/calendar';
+	import { IconButton } from '$uix/eidos/components/icon-button';
+	import { ChevronRight } from '$uix/eidos/components/icon';
 	import type { CalendarNextButtonProps } from './types';
 
-	let { children: bodyContent, ...rest }: CalendarNextButtonProps = $props();
+	let {
+		'aria-label': ariaLabel,
+		children: bodyContent,
+		...rest
+	}: CalendarNextButtonProps = $props();
+
+	const eidos = ActiveEidos.require();
+	const label = $derived(ariaLabel ?? eidos.langs.ts('#?common.calendar.next-month|Next month'));
 </script>
 
 <Calendar.NextButton {...rest}>
-	{@render bodyContent?.()}
+	{#snippet child({ props }: { props: Record<string, unknown> })}
+		<IconButton {...props} variant="ghost" size="sm" aria-label={label}>
+			{#if bodyContent}{@render bodyContent()}{:else}<ChevronRight />{/if}
+		</IconButton>
+	{/snippet}
 </Calendar.NextButton>

src/uix/eidos/components/calendar/calendar-prev-button.svelte

@@ -1,10 +1,30 @@
 <script lang="ts">
+	/**
+	 * Eidos `Calendar.PrevButton` — composes the system `<IconButton>` (which itself
+	 * composes `<Button>`) via soma's `child` snippet, instead of styling a bespoke
+	 * native `<button>`. The back-chevron glyph plus sizing / hover / focus /
+	 * disabled / a11y all come from the primitive — no duplicated chrome.
+	 */
+	import { ActiveEidos } from '$uix/eidos';
 	import * as Calendar from '$soma/components/calendar';
+	import { IconButton } from '$uix/eidos/components/icon-button';
+	import { ChevronLeft } from '$uix/eidos/components/icon';
 	import type { CalendarPrevButtonProps } from './types';
 
-	let { children: bodyContent, ...rest }: CalendarPrevButtonProps = $props();
+	let {
+		'aria-label': ariaLabel,
+		children: bodyContent,
+		...rest
+	}: CalendarPrevButtonProps = $props();
+
+	const eidos = ActiveEidos.require();
+	const label = $derived(ariaLabel ?? eidos.langs.ts('#?common.calendar.prev-month|Previous month'));
 </script>
 
 <Calendar.PrevButton {...rest}>
-	{@render bodyContent?.()}
+	{#snippet child({ props }: { props: Record<string, unknown> })}
+		<IconButton {...props} variant="ghost" size="sm" aria-label={label}>
+			{#if bodyContent}{@render bodyContent()}{:else}<ChevronLeft />{/if}
+		</IconButton>
+	{/snippet}
 </Calendar.PrevButton>

src/uix/eidos/components/calendar/calendar-year-select.svelte

@@ -1,16 +1,80 @@
 <script lang="ts">
-	import * as Calendar from '$soma/components/calendar';
+	/**
-	import type { CalendarYearSelectProps, CalendarYearSelectSnippetProps } from './types';
+	 * Eidos `<Calendar.YearSelect>` — year chooser. A NON-MODAL popover whose
+	 * trigger shows the current year + a chevron and whose content is the reused
+	 * `YearGrid` (a decade page with prev/next). Picking a year sets the calendar
+	 * year and closes. Replaces the former native `<select>`.
+	 *
+	 * The decade browsing drives a LOCAL nav-year (re-seeded from the calendar each
+	 * time the popover opens) instead of syncing back into the calendar — that
+	 * decoupling avoids a placeholder feedback loop. No `value` is passed so the
+	 * grid never fires a select on mount and slams the popover shut.
+	 */
+	import { CalendarProvider } from '$soma/components/calendar';
+	import { ChevronDown, ChevronLeft, ChevronRight } from '$uix/eidos/components/icon';
+	import { Button } from '$uix/eidos/components/button';
+	import Popover from '../popover';
+	import YearGrid from '../year-grid';
+	import type { YearValue, YearPlaceholder, YearGridProviderSnippetProps } from '$soma/components/year-grid';
 
-	let { children: bodyContent, ...rest }: CalendarYearSelectProps = $props();
+	const provider = CalendarProvider.require();
+	let open = $state(false);
+
+	const selectedYear = $derived(provider.opts.placeholder.current.year);
+	// Local decade browsing — re-seeded from the calendar on each open so the
+	// page starts on the selected year.
+	let navYear = $state(provider.opts.placeholder.current.year);
+	$effect(() => {
+		if (open) navYear = provider.opts.placeholder.current.year;
+	});
+
+	const yearLabel = $derived(provider.formatYear(selectedYear));
+	const placeholder = $derived<YearPlaceholder>({ year: navYear });
+	// Highlight the selected year with the SELECTED (filled) style.
+	const value = $derived<YearValue>({ year: selectedYear });
+
+	function onPlaceholderChange(next: YearPlaceholder): void {
+		navYear = next.year;
+	}
+	function onValueChange(next: YearValue | undefined): void {
+		if (!next) return;
+		provider.setYear(next.year);
+		open = false;
+	}
 </script>
 
-{#if bodyContent}
+<Popover bind:open modal={false}>
-	<Calendar.YearSelect {...rest}>
+	<Popover.Trigger data-calendar-year-select>
-		{#snippet children(snippetProps: CalendarYearSelectSnippetProps)}
+		{#snippet child({ props }: { props: Record<string, unknown> })}
-			{@render bodyContent(snippetProps)}
+			<Button {...props} variant="ghost" size="sm">
+				<span data-calendar-select-label>{yearLabel}</span>
+				<ChevronDown data-calendar-select-chevron aria-hidden="true" />
+			</Button>
 		{/snippet}
-	</Calendar.YearSelect>
+	</Popover.Trigger>
-{:else}
+	<Popover.Portal>
-	<Calendar.YearSelect {...rest} />
+		<Popover.Content data-calendar-select-popover>
-{/if}
+			<YearGrid
+				{placeholder}
+				{value}
+				pageAligned={false}
+				locale={provider.effectiveLocale}
+				{onPlaceholderChange}
+				{onValueChange}
+			>
+				{#snippet children({ years }: YearGridProviderSnippetProps)}
+					<YearGrid.Header>
+						<YearGrid.PrevButton><ChevronLeft aria-hidden="true" /></YearGrid.PrevButton>
+						<YearGrid.Heading />
+						<YearGrid.NextButton><ChevronRight aria-hidden="true" /></YearGrid.NextButton>
+					</YearGrid.Header>
+					<YearGrid.Grid>
+						{#each years as year (year)}
+							<YearGrid.Cell {year} />
+						{/each}
+					</YearGrid.Grid>
+				{/snippet}
+			</YearGrid>
+		</Popover.Content>
+	</Popover.Portal>
+</Popover>

src/uix/eidos/components/calendar/calendar-year-view.svelte

@@ -0,0 +1,50 @@
+<script lang="ts">
+	/**
+	 * Eidos `<Calendar.YearView>` — the year (decade) grid shown when the
+	 * calendar's navigation view is `'year'`. Reuses the eidos `<YearGrid>`;
+	 * picking a year sets the calendar's placeholder year and drills back DOWN to
+	 * the month grid. Top of the drill, so the heading is a plain label.
+	 *
+	 * Drives a LOCAL navigation year (re-seeded on each entry) and passes no
+	 * `value`, mirroring `<Calendar.MonthView>` — avoids the placeholder feedback
+	 * loop and any spurious select on mount.
+	 */
+	import { CalendarProvider } from '$soma/components/calendar';
+	import YearGrid from '../year-grid';
+	import type { YearPlaceholder, YearGridProviderSnippetProps } from '$soma/components/year-grid';
+	import type { YearGridSize } from '../year-grid';
+
+	let { size = 'md' }: { size?: YearGridSize } = $props();
+
+	const provider = CalendarProvider.require();
+
+	let navYear = $state(provider.opts.placeholder.current.year);
+	$effect(() => {
+		if (provider.view === 'year') navYear = provider.opts.placeholder.current.year;
+	});
+	const placeholder = $derived<YearPlaceholder>({ year: navYear });
+
+	function onPlaceholderChange(next: YearPlaceholder): void {
+		navYear = next.year;
+	}
+	function onValueChange(next: { year: number } | undefined): void {
+		if (next) provider.selectYearView(next.year);
+	}
+</script>
+
+{#if provider.view === 'year'}
+	<YearGrid {size} {placeholder} {onPlaceholderChange} {onValueChange}>
+		{#snippet children({ years }: YearGridProviderSnippetProps)}
+			<YearGrid.Header>
+				<YearGrid.PrevButton>‹</YearGrid.PrevButton>
+				<YearGrid.Heading />
+				<YearGrid.NextButton>›</YearGrid.NextButton>
+			</YearGrid.Header>
+			<YearGrid.Grid>
+				{#each years as year (year)}
+					<YearGrid.Cell {year} />
+				{/each}
+			</YearGrid.Grid>
+		{/snippet}
+	</YearGrid>
+{/if}

src/uix/eidos/components/calendar/calendar.css

@@ -153,84 +153,49 @@
 	text-align: center;
 }
 
-[data-calendar-prev-button],
+/* Prev / Next compose the system <IconButton> (see calendar-prev-button.svelte /
-[data-calendar-next-button] {
+   calendar-next-button.svelte). Their box, hover, focus-ring, disabled and a11y
-	display: inline-flex;
+   all come from the primitive — no bespoke chrome here. */
-	align-items: center;
-	justify-content: center;
-	flex: 0 0 auto;
-	inline-size: var(--_calendar-control-size);
-	block-size: var(--_calendar-control-size);
-	padding: 0;
-	border: var(--calendar-control-border-width) solid var(--calendar-control-border);
-	border-radius: var(--calendar-control-radius);
-	background: var(--calendar-control-bg);
-	color: var(--calendar-control-color);
-	cursor: pointer;
-	transition:
-		background var(--calendar-transition-duration) var(--calendar-transition-ease),
-		border-color var(--calendar-transition-duration) var(--calendar-transition-ease),
-		color var(--calendar-transition-duration) var(--calendar-transition-ease),
-		box-shadow var(--calendar-transition-duration) var(--calendar-transition-ease);
-}
 
-[data-calendar-prev-button]:hover,
-[data-calendar-next-button]:hover {
-	border-color: var(--calendar-control-border-hover);
-	background: var(--calendar-control-bg-hover);
-	color: var(--calendar-control-color-hover);
-}
-
-[data-calendar-prev-button]:focus-visible,
-[data-calendar-next-button]:focus-visible,
-[data-calendar-month-select]:focus-visible,
-[data-calendar-year-select]:focus-visible,
 [data-calendar-day]:focus-visible {
 	outline: var(--focus-ring-width) solid var(--focus-ring-color);
 	outline-offset: 0;
 }
 
-[data-calendar-prev-button][data-disabled],
+/* The month / year trigger is now the system <Button> (composed via the
-[data-calendar-next-button][data-disabled],
+   Popover.Trigger `child` snippet). Its box / border / bg / hover / focus /
-[data-calendar-month-select][data-disabled],
+   disabled all come from the primitive — only the label font + chevron remain. */
-[data-calendar-year-select][data-disabled] {
-	cursor: not-allowed;
-	opacity: var(--calendar-disabled-opacity);
-}
 
-[data-calendar-month-select],
+[data-calendar-select-label] {
-[data-calendar-year-select] {
+	/* The Button's sm size is 14px; bump the label to the picker font (16px) so
-	min-inline-size: 0;
+	   the month/year text matches the calendar. Set on the label (not the Button
-	block-size: var(--_calendar-control-size);
+	   token) so it wins over the inherited Button font without a specificity war. */
-	padding-inline: var(--calendar-select-px);
+	font-size: var(--_calendar-font-size);
-	border: var(--calendar-control-border-width) solid var(--calendar-control-border);
+	white-space: nowrap;
-	border-radius: var(--calendar-control-radius);
-	background: var(--calendar-control-bg);
-	color: var(--calendar-control-color);
-	font: inherit;
-	cursor: pointer;
-	transition:
-		background var(--calendar-transition-duration) var(--calendar-transition-ease),
-		border-color var(--calendar-transition-duration) var(--calendar-transition-ease),
-		color var(--calendar-transition-duration) var(--calendar-transition-ease),
-		box-shadow var(--calendar-transition-duration) var(--calendar-transition-ease);
 }
 
-[data-calendar-month-select] {
+[data-calendar-select-chevron] {
-	min-inline-size: var(--calendar-select-min-width);
+	flex: 0 0 auto;
-	inline-size: calc(var(--_calendar-day-size) * 2.35);
+	inline-size: var(--_calendar-font-size);
+	block-size: var(--_calendar-font-size);
+	opacity: 0.6;
 }
 
-[data-calendar-year-select] {
+/* The grid sits inside the popover's own surface — flatten its standalone
-	min-inline-size: var(--calendar-select-min-width);
+   surface (border / bg / shadow / outer padding) so the panel isn't doubled. */
-	inline-size: calc(var(--_calendar-day-size) * 2.15);
+[data-calendar-select-popover] :is([data-month-grid], [data-year-grid]) {
+	border: none;
+	background: transparent;
+	box-shadow: none;
+	padding: 0;
 }
 
-[data-calendar-month-select]:hover,
+/* Spanish (and other locales') Intl month abbreviations come back lowercase
-[data-calendar-year-select]:hover {
+   ("ene", "feb"); capitalize so the month reads the same regardless of locale —
-	border-color: var(--calendar-control-border-hover);
+   matching the English "Jan" / "Feb". */
-	background: var(--calendar-control-bg-hover);
+[data-calendar-month-select],
-	color: var(--calendar-control-color-hover);
+[data-calendar-select-popover] [data-month-grid-cell] {
+	text-transform: capitalize;
 }
 
 [data-calendar-grid] {

src/uix/eidos/components/calendar/index.ts

@@ -1,10 +1,13 @@
 import CalendarComponent from './calendar.svelte'
 import Header from './calendar-header.svelte'
 import Heading from './calendar-heading.svelte'
+import HeadingTrigger from './calendar-heading-trigger.svelte'
 import PrevButton from './calendar-prev-button.svelte'
 import NextButton from './calendar-next-button.svelte'
 import MonthSelect from './calendar-month-select.svelte'
 import YearSelect from './calendar-year-select.svelte'
+import MonthView from './calendar-month-view.svelte'
+import YearView from './calendar-year-view.svelte'
 import Grid from './calendar-grid.svelte'
 import GridHead from './calendar-grid-head.svelte'
 import GridBody from './calendar-grid-body.svelte'
@@ -16,10 +19,13 @@ import Day from './calendar-day.svelte'
 type CalendarNamespace = typeof CalendarComponent & {
 	Header: typeof Header
 	Heading: typeof Heading
+	HeadingTrigger: typeof HeadingTrigger
 	PrevButton: typeof PrevButton
 	NextButton: typeof NextButton
 	MonthSelect: typeof MonthSelect
 	YearSelect: typeof YearSelect
+	MonthView: typeof MonthView
+	YearView: typeof YearView
 	Grid: typeof Grid
 	GridHead: typeof GridHead
 	GridBody: typeof GridBody
@@ -32,10 +38,13 @@ type CalendarNamespace = typeof CalendarComponent & {
 const Calendar = CalendarComponent as CalendarNamespace
 Calendar.Header = Header
 Calendar.Heading = Heading
+Calendar.HeadingTrigger = HeadingTrigger
 Calendar.PrevButton = PrevButton
 Calendar.NextButton = NextButton
 Calendar.MonthSelect = MonthSelect
 Calendar.YearSelect = YearSelect
+Calendar.MonthView = MonthView
+Calendar.YearView = YearView
 Calendar.Grid = Grid
 Calendar.GridHead = GridHead
 Calendar.GridBody = GridBody

src/uix/soma/components/calendar/calendar-provider.svelte.ts

@@ -38,6 +38,7 @@ import type {
 	CalendarCellSnippetProps,
 	CalendarDaySnippetProps,
 	CalendarMonthSelectSnippetProps,
+	CalendarView,
 	CalendarYearSelectSnippetProps
 } from './types';
 
@@ -133,6 +134,13 @@ export class CalendarProvider {
 	headingId = state('');
 	/** Live-region text for announcements. */
 	announcement = $state('');
+	/**
+	 * Navigation view (Ark/Mantine/MUI pattern): the day grid switches in-place
+	 * to a month grid then a year grid for fast navigation — no native `<select>`,
+	 * no nested popover. The `MonthView` / `YearView` parts render the reused
+	 * `MonthGrid` / `YearGrid` when active; the `Heading` advances the view.
+	 */
+	view = $state<CalendarView>('day');
 	private lastLoggedValidationKey: string | null = null;
 
 	private constructor(opts: CalendarOpts) {
@@ -347,6 +355,29 @@ export class CalendarProvider {
 		this.setPlaceholder(this.opts.placeholder.current.set({ year }), target);
 	}
 
+	// ── Navigation view (day ↔ month ↔ year) ──────────────────────────────────
+
+	setView(view: CalendarView): void {
+		this.view = view;
+	}
+
+	/** Heading click: drill UP one level (day → month → year). */
+	advanceView(): void {
+		this.view = this.view === 'day' ? 'month' : 'year';
+	}
+
+	/** Month grid select: set the placeholder year+month and drill back DOWN to days. */
+	selectMonthView(year: number, month: number, target?: HTMLElement): void {
+		this.setPlaceholder(this.opts.placeholder.current.set({ year, month }), target);
+		this.view = 'day';
+	}
+
+	/** Year grid select: set the placeholder year and drill back DOWN to months. */
+	selectYearView(year: number, target?: HTMLElement): void {
+		this.setYear(year, target);
+		this.view = 'month';
+	}
+
 	private announceNavigation(): void {
 		if (!this.opts.announceNavigation.current) return;
 		this.announcement = this.headingValue;

src/uix/soma/components/calendar/exports.ts

@@ -13,7 +13,13 @@ export { default as HeadCell } from './components/calendar-head-cell.svelte';
 export { default as Cell } from './components/calendar-cell.svelte';
 export { default as Day } from './components/calendar-day.svelte';
 
+// The provider class is exported so the eidos view-switch parts
+// (Heading button, MonthView, YearView) can read `view` + drive
+// `advanceView` / `selectMonthView` / `selectYearView` off the live context.
+export { CalendarProvider } from './calendar-provider.svelte';
+
 export type {
+	CalendarView,
 	CalendarProps,
 	CalendarHeaderProps,
 	CalendarHeadingProps,

src/uix/soma/components/calendar/types.ts

@@ -15,6 +15,15 @@ import type {
 import type { DateValue, DateMatcher, Month, WeekStartsOn, DateOrder } from '$libs/days';
 import type { CalendarBoundsValidationStatus } from './helpers';
 
+// ── Navigation view ──────────────────────────────────────────────────────────
+
+/**
+ * The calendar's active navigation view. The day grid switches in-place to a
+ * month grid then a year grid (Ark/Mantine/MUI pattern) — no native `<select>`,
+ * no nested popover.
+ */
+export type CalendarView = 'day' | 'month' | 'year';
+
 // ── Snippet props ────────────────────────────────────────────────────────────
 
 /** Snippet props exposed by the root `Calendar.Provider`. */

src/uix/soma/components/year-grid/components/year-grid.svelte

@@ -26,6 +26,7 @@
 		dir,
 		locale,
 		decadeSize = 12,
+		pageAligned = true,
 		ariaLabel,
 		children,
 		child,
@@ -59,6 +60,7 @@
 		dir: readableActive(() => dir ?? soma?.prefs.getDir() ?? 'ltr'),
 		locale: readableActive(() => locale ?? ''),
 		decadeSize: readableActive(() => decadeSize),
+		pageAligned: readableActive(() => pageAligned),
 		ariaLabel: readableActive(() => ariaLabel)
 	});
 

src/uix/soma/components/year-grid/types.ts

@@ -75,6 +75,12 @@ type YearGridBaseProps = {
 	 * @default 12
 	 */
 	decadeSize?: number;
+	/**
+	 * When `true` (default) the page aligns to a `decadeSize` boundary (a window of
+	 * past + future years). When `false` the page starts at the placeholder year.
+	 * @default true
+	 */
+	pageAligned?: boolean;
 	/** `aria-label` for the provider root. Localized when omitted. */
 	ariaLabel?: string;
 };

src/uix/soma/components/year-grid/year-grid-provider.svelte.ts

@@ -46,6 +46,14 @@ export interface YearGridOpts
 			dir: 'ltr' | 'rtl';
 			locale: string;
 			decadeSize: number;
+			/**
+			 * When `true` (default) the page aligns to a `decadeSize` boundary
+			 * (e.g. 2016–2027 for 2026) — a window of past + future years, best for
+			 * picking a distant year. When `false` the page STARTS at the placeholder
+			 * year (2026–2037) — best when the grid opens on the current value and
+			 * forward years matter most (e.g. a calendar's year chooser).
+			 */
+			pageAligned: boolean;
 			ariaLabel: string | undefined;
 		}> {
 	onValueChange?: OnChangeFn<YearValue | undefined>;
@@ -99,6 +107,7 @@ export class YearGridProvider {
 
 	readonly pageStart = $derived.by(() => {
 		const placeholder = this.opts.placeholder.current.year;
+		if (this.opts.pageAligned.current === false) return placeholder;
 		const size = this.decadeSize;
 		return placeholder - ((placeholder % size + size) % size);
 	});

web/routes/uix/components/calendar/+page.svelte

@@ -388,15 +388,15 @@
 
 {#snippet calendarBody({ months, weekdays, validationMessage }: CalendarProviderSnippetProps)}
 	<Calendar.Header>
-		<Calendar.PrevButton aria-label="Previous month">&lt;</Calendar.PrevButton>
+		<Calendar.PrevButton aria-label="Previous month" />
 		<div data-calendar-header-controls>
 			<Calendar.MonthSelect />
 			<Calendar.YearSelect />
 		</div>
-		<Calendar.NextButton aria-label="Next month">&gt;</Calendar.NextButton>
+		<Calendar.NextButton aria-label="Next month" />
 	</Calendar.Header>
 	<div
-		style={`display:grid;grid-template-columns:repeat(${numberOfMonths},max-content);gap:var(--uix-space-4);align-items:start;max-inline-size:100%;overflow:auto;`}
+		style={`display:grid;grid-template-columns:repeat(${numberOfMonths},max-content);gap:var(--uix-space-4);align-items:start;justify-content:safe center;max-inline-size:100%;overflow:auto;`}
 	>
 		{#each months as month (month.value.toString())}
 			<div data-calendar-month-panel>

web/routes/uix/components/date-picker/+page.svelte

@@ -1196,12 +1196,12 @@
 
 {#snippet calendarBody({ months, weekdays, validationMessage }: DatePickerCalendarSnippetProps)}
 	<DatePicker.Header>
-		<DatePicker.PrevButton aria-label="Previous month">&lt;</DatePicker.PrevButton>
+		<DatePicker.PrevButton aria-label="Previous month" />
 		<div data-calendar-header-controls>
 			<DatePicker.MonthSelect />
 			<DatePicker.YearSelect />
 		</div>
-		<DatePicker.NextButton aria-label="Next month">&gt;</DatePicker.NextButton>
+		<DatePicker.NextButton aria-label="Next month" />
 	</DatePicker.Header>
 
 	{#if validationMessage}