Wrap a fixed tab's long label to a second line

Plan step 46, M3 § Tabs: "Labels: single row by default; may wrap to a
max second line if needed with truncation, or use scrollable tabs to
give longer titles more room." In fixed tabs (<x-tabs>, <x-section-nav>
up to four sections) the label's text, now its own data-md-tab-text in
both views, wraps and truncates at two lines. The tab's 48px (64px
stacked) is a minimum, the bar stretches its tabs to one height, and the
content stretches with them, so the indicator stays on the divider.
Scrollable tabs keep one row. SealShare's "Two-Factor Auth" and
"Appearance" showed an ellipsis at 600px.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

resources/css/components/section-nav.css

@@ -16,8 +16,11 @@
  * `aria-current="page"` takes the same active indicator and colour tabs.css already draws for
  * `aria-selected="true"` (N-21), so nothing here repeats a rule tabs.css owns; the only addition is
  * this bar's own list items — flex rows, so tabs.css's `li > [data-md-tab]` share of the width
- * applies, and `min-inline-size: 0`, so a long title still truncates — which `<x-tabs>`'s buttons,
- * direct children of the bar, never need. The picker's trigger is not one of M3's controls
+ * applies, and `min-inline-size: 0`, so a long title in a fixed row wraps to its second line and
+ * truncates there (tabs.css, M3's "may wrap to a max second line if needed with truncation")
+ * instead of widening its item — which `<x-tabs>`'s buttons, direct children of the bar, never
+ * need. Its tabs render `<x-tabs>`'s label anatomy (`data-md-tab-label` around
+ * `data-md-tab-text`), so that rule draws both. The picker's trigger is not one of M3's controls
  * — an outlined field-like button naming the current section, 48px tall to meet the target M3 asks
  * for everywhere, in body-large type (a text class on the view, `md-type-body-lg
  * md-ink md-text-start`, since it is prose on a plain button rather than a component's own type).

resources/css/components/tabs.css

@@ -1,8 +1,8 @@
 /*
  * `<x-tabs>`, `<x-tab>`: M3's tabs (PrimaryNavigationTabTokens.kt, SecondaryNavigationTabTokens.kt,
  * androidx Compose Material 3, Apache-2.0; docs/reference/m3/components-navigation-selection-inputs.md
- * § Tabs) — a 48px tablist on the surface over an outline-variant divider (64px when a primary tab
- * stacks its icon over its label), title-small labels in on-surface-variant, the chosen tab's in
+ * § Tabs) — a tablist of tabs at least 48px tall on the surface over an outline-variant divider
+ * (64px when a primary tab stacks its icon over its label), title-small labels in on-surface-variant, the chosen tab's in
  * primary (primary tabs) or on-surface (secondary tabs).
  *
  *   [data-md-tabs]                 min-width: 0
@@ -11,8 +11,18 @@
  *       [data-md-tab]              role="tab"
  *         [data-md-tab-content]    [data-md-icon] (optional), [data-md-tab-label],
  *                                  [data-md-tab-indicator]
+ *           [data-md-tab-label]    [data-md-tab-text], [data-md-badge] (optional)
  *   [data-md-tab-panel]            role="tabpanel", hidden server-side until chosen (N-05)
  *
+ * "Labels: single row by default; may wrap to a max second line if needed with truncation, or use
+ * scrollable tabs to give longer titles more room" (§ Tabs, "Behaviour and guidelines"). A fixed
+ * tab shares the row equally, so its label keeps one row while it fits its share, then wraps to a
+ * second line and truncates that one with an ellipsis. 48px (64px stacked) is the tab's minimum,
+ * not its height: the tab grows to hold the second line, and the bar's flex row stretches every
+ * tab to the tallest, so the tabs keep one height, each content box fills its tab, and every
+ * indicator stays on the divider under its tab's content. A scrollable tab is as wide as its label
+ * and keeps it on one row, the room M3 gives longer titles instead.
+ *
  * The active indicator is drawn in every tab and shown under the chosen one, so it is right before
  * Alpine starts and after a morph: 3px with rounded top corners under the content of a primary tab
  * (at least 24px wide, inset 2px at each side — N-18), 2px across the whole of a secondary one.
@@ -73,7 +83,7 @@
         display: flex;
         flex: 1 1 0%;
         min-width: 90px;
-        height: 48px;
+        min-height: 48px;
         align-items: center;
         justify-content: center;
         padding-inline: var(--md-sys-measurement-space200);
@@ -94,7 +104,7 @@
     }
 
     [data-md-tabs-bar][data-md-stacked] [data-md-tab] {
-        height: 64px;
+        min-height: 64px;
     }
 
     /* The state layer covers the tab and the ring's room around it, so the wash meets the divider. */
@@ -149,10 +159,12 @@
         background-color: transparent;
     }
 
+    /* Stretched rather than 100% tall, so it fills a tab that grew past its minimum too, and the
+       primary indicator at its foot lands on the divider in every tab of the bar. */
     [data-md-tab-content] {
         position: relative;
         display: inline-flex;
-        height: 100%;
+        align-self: stretch;
         min-width: 24px;
         align-items: center;
         justify-content: center;
@@ -166,10 +178,24 @@
 
     [data-md-tab-label] {
         display: inline-flex;
+        min-width: 0;
         align-items: center;
         gap: var(--md-sys-measurement-space75);
     }
 
+    /* A fixed tab's label: one row while it fits, then a second, truncated (the M3 line above).
+       The tab's own nowrap still holds the badge and a scrollable tab's label to one row. */
+    [data-md-tabs-bar]:not([data-md-scrollable]) [data-md-tab-text] {
+        display: -webkit-box;
+        min-width: 0;
+        overflow: hidden;
+        -webkit-box-orient: vertical;
+        -webkit-line-clamp: 2;
+        text-align: center;
+        text-overflow: ellipsis;
+        white-space: normal;
+    }
+
     /* Primary indicators are inset 2dp at each side (N-18); both variants sit on the divider, which
        the ring's room has pushed below the tab. */
     [data-md-tab-indicator] {

resources/views/components/section-nav.blade.php

@@ -13,7 +13,11 @@
      The page's URL is `Livewire::originalUrl()`: while a Livewire component on the page updates, the
      request is Livewire's update endpoint, and comparing with it left no section lit.
 
-     Up to four sections share the row as fixed tabs. From five the row is M3's scrollable tab bar
+     Up to four sections share the row as fixed tabs, a title too long for its share wrapping to
+     a second line and truncating there, the bar growing to hold it, as M3 lets a fixed tab's label
+     ("may wrap to a max second line if needed with truncation"); each tab renders `<x-tabs>`'s
+     label anatomy, `data-md-tab-label` around `data-md-tab-text` and the badge, so tabs.css draws
+     both alike. From five the row is M3's scrollable tab bar
      — each tab as wide as its own label, the set scrolling sideways, offset 52dp from the leading
      edge so it reads as scrollable — which is M3's own answer to a row that will not fit, and the
      one its accessibility page blesses ("horizontal scrolling tabs meet accessibility requirements
@@ -36,7 +40,8 @@
     $isCurrent = fn (array $item): bool => ($item['active'] ?? false) || (filled($item['url'] ?? null) && $page === url($item['url']));
     $current = collect($items)->first($isCurrent) ?? ($items[0] ?? null);
 
-    // Four fit a row at the widths this bar is used at; from five they are M3's scrollable tabs.
+    // Up to four share the row as fixed tabs, a long title wrapping to a second line and truncating
+    // there (tabs.css); from five they are M3's scrollable tabs, which give longer titles room.
     $scrollable = count($items) >= 5;
 @endphp
 
@@ -77,10 +82,12 @@
                             @isset($item['icon'])
                                 <x-livewire-material::icon :name="$item['icon']" :filled="$on" :size="20" />
                             @endisset
-                            <span class="md-truncate">{{ $item['title'] }}</span>
+                            <span data-md-tab-label>
+                                <span data-md-tab-text>{{ $item['title'] }}</span>
                                 @if (filled($item['badge'] ?? null))
                                     <x-livewire-material::badge :value="$item['badge']" />
                                 @endif
+                            </span>
                             <span data-md-tab-indicator aria-hidden="true"></span>
                         </span>
                     </a>

resources/views/components/tabs.blade.php

@@ -12,12 +12,16 @@
      the label, in primary) or `secondary` (under the whole tab, for tabs inside a section);
      `stacked` puts a primary tab's icon over its label (64px); `scrollable` lets tabs keep their
      own width and scroll sideways instead of sharing the width equally, offset 52dp from the
-     leading edge so it reads as scrollable (N-10, resources/css/components/tabs.css).
+     leading edge so it reads as scrollable (N-10, resources/css/components/tabs.css). A fixed
+     tab's label too long for its share wraps to a second line and truncates there, the whole bar
+     growing to hold it; a scrollable tab keeps its label on one line (M3: "may wrap to a max
+     second line if needed with truncation, or use scrollable tabs to give longer titles more
+     room").
 
      The root renders `data-md-tabs`; the bar is `data-md-tabs-bar` with `data-md-variant`,
      `data-md-stacked` and `data-md-scrollable`, holding `data-md-tab` buttons (each
-     `data-md-tab-content`, `data-md-tab-label` and `data-md-tab-indicator`). Imports icon.css and
-     badge.css for what the view renders. --}}
+     `data-md-tab-content`, `data-md-tab-label` around the label's `data-md-tab-text` and its badge,
+     and `data-md-tab-indicator`). Imports icon.css and badge.css for what the view renders. --}}
 
 @props([
     'tabs' => [],
@@ -84,7 +88,7 @@
                         <x-livewire-material::icon :name="$tab['icon']" />
                     @endisset
                     <span data-md-tab-label>
-                        {{ $tab['label'] }}
+                        <span data-md-tab-text>{{ $tab['label'] }}</span>
                         @if (filled($tab['badge'] ?? null))
                             <x-livewire-material::badge :value="$tab['badge']" />
                         @endif

tests/Browser/BarsTest.php

@@ -54,7 +54,7 @@ class BarsProbe extends Component
                     <x-theme-toggle mode="cycle" id="cycle" />
                     <x-theme-toggle mode="picker" />
 
-                    <x-section-nav :items="[['title' => 'Profile', 'url' => '#profile', 'active' => true], ['title' => 'Security', 'url' => '#security'], ['title' => 'Advanced notification settings', 'url' => '#notifications']]" no-wire-navigate />
+                    <x-section-nav :items="[['title' => 'Profile', 'url' => '#profile', 'active' => true], ['title' => 'Security', 'url' => '#security'], ['title' => 'Advanced notification settings', 'url' => '#notifications'], ['title' => 'Appearance', 'url' => '#appearance']]" no-wire-navigate />
 
                     <div style="height: 200vh"></div>
                 </div>
@@ -192,11 +192,51 @@ it('shares the row width equally between the section nav\'s items, whatever thei
     $widths = "[...document.querySelectorAll('[data-md-section-nav] [data-md-tabs-bar] > li')].map((li) => Math.round(li.getBoundingClientRect().width))";
 
     barsProbe()
-        ->assertScript("{$widths}.length === 3")
+        ->assertScript("{$widths}.length === 4")
         ->assertScript("new Set({$widths}).size === 1")
         ->assertNoJavaScriptErrors();
 });
 
+/**
+ * Plan step 46, M3 § Tabs: "Labels: single row by default; may wrap to a max second line if needed
+ * with truncation". Four sections are fixed tabs; at a 600px window a long title no longer fits its
+ * share, so it takes a second line (SealShare's "Two-Factor Auth" showed an ellipsis on one) inside
+ * its tab, the row's tabs keep one height, and the chosen tab's indicator stays on the divider.
+ */
+it('wraps a long section title to a second line in a fixed row, keeping the tabs one height and the indicator on the divider', function () {
+    $tabs = "[...document.querySelectorAll('[data-md-section-nav] [data-md-tab]')]";
+    $long = "document.querySelector('[data-md-section-nav] [data-md-tab][href=\"#notifications\"]')";
+
+    barsProbe()
+        ->resize(600, 800)
+        ->assertScript("getComputedStyle(document.querySelector('[data-md-section-nav] nav')).display !== 'none'")
+        ->assertScript("{$tabs}.length === 4 && ! document.querySelector('[data-md-section-nav] [data-md-tabs-bar]').hasAttribute('data-md-scrollable')")
+        // Two lines of the label's own line height, not one truncated row.
+        ->assertScript("(() => { const text = {$long}.querySelector('[data-md-tab-text]'); return Math.round(text.getBoundingClientRect().height / parseFloat(getComputedStyle(text).lineHeight)) === 2; })()")
+        // Inside its tab, both ways.
+        ->assertScript("(() => { const tab = {$long}.getBoundingClientRect(); const text = {$long}.querySelector('[data-md-tab-text]').getBoundingClientRect(); return text.left >= tab.left - 0.5 && text.right <= tab.right + 0.5 && text.top >= tab.top - 0.5 && text.bottom <= tab.bottom + 0.5; })()")
+        // One height for the row, at least M3's 48px.
+        ->assertScript("new Set({$tabs}.map((tab) => Math.round(tab.getBoundingClientRect().height))).size === 1 && {$tabs}[0].getBoundingClientRect().height >= 48")
+        // The chosen tab's indicator: shown, under its content, on the divider, within its tab.
+        ->assertScript(<<<'JS'
+            (() => {
+                const tab = document.querySelector('[data-md-section-nav] [data-md-tab][aria-current="page"]');
+                const bar = tab.closest('[data-md-tabs-bar]');
+                const indicator = tab.querySelector('[data-md-tab-indicator]');
+                const box = tab.getBoundingClientRect();
+                const content = tab.querySelector('[data-md-tab-content]').getBoundingClientRect();
+                const line = indicator.getBoundingClientRect();
+                const divider = bar.getBoundingClientRect().bottom - parseFloat(getComputedStyle(bar).borderBottomWidth);
+
+                return getComputedStyle(indicator).opacity === '1'
+                    && line.top >= content.bottom - 0.5
+                    && Math.abs(line.bottom - divider) <= 1
+                    && line.left >= box.left - 0.5 && line.right <= box.right + 0.5;
+            })()
+            JS)
+        ->assertNoJavaScriptErrors();
+});
+
 class AppBarOverflowProbe extends Component
 {
     public int $stars = 0;

tests/Feature/Components/TabsTest.php

@@ -123,6 +123,56 @@ it('keeps the tab bar on M3\'s offsets, indicator inset and focus ring', functio
         ->toBe(['color' => 'var(--md-sys-color-primary)']);
 });
 
+/**
+ * Plan step 46, M3 § Tabs: "Labels: single row by default; may wrap to a max second line if needed
+ * with truncation, or use scrollable tabs to give longer titles more room." Both views render the
+ * text of a label in its own `data-md-tab-text`, so the one rule in tabs.css clamps it.
+ */
+it('renders a label\'s text in its own hook, in tabs and section tabs alike', function () {
+    expect((string) $this->blade('<x-tabs :tabs="[[\'name\' => \'people\', \'label\' => \'People with access\', \'badge\' => 3]]" />'))
+        ->toMatch('/<span data-md-tab-label>\s*<span data-md-tab-text>People with access<\/span>\s*<span[^>]*data-md-badge/')
+        ->and((string) $this->blade('<x-section-nav :items="[[\'title\' => \'Two-factor authentication\', \'url\' => \'/security\', \'badge\' => 1]]" no-wire-navigate />'))
+        ->toMatch('/<span data-md-tab-label>\s*<span data-md-tab-text>Two-factor authentication<\/span>\s*<span[^>]*data-md-badge/');
+});
+
+it('lets a fixed tab\'s label wrap to a second line and truncate there, and a scrollable one keep its row', function () {
+    $css = ComponentStylesheet::read('tabs');
+
+    expect($css->declarations('[data-md-tab]'))
+        // M3's 48px is the tab's minimum: it grows to hold a second line, and the bar stretches the rest.
+        ->toHaveKey('min-height', '48px')
+        ->not->toHaveKey('height')
+        ->toHaveKey('min-width', '90px')
+        // The single row a scrollable tab's label and every badge keep.
+        ->toHaveKey('white-space', 'nowrap')
+        ->and($css->declarations('[data-md-tabs-bar][data-md-stacked] [data-md-tab]'))
+        ->toBe(['min-height' => '64px'])
+        // The content fills a grown tab, so a primary indicator at its foot stays on the divider.
+        ->and($css->declarations('[data-md-tab-content]'))
+        ->toHaveKey('align-self', 'stretch')
+        ->not->toHaveKey('height')
+        ->and($css->declarations('[data-md-tab-label]'))
+        ->toHaveKey('min-width', '0')
+        ->and($css->declarations('[data-md-tabs-bar]:not([data-md-scrollable]) [data-md-tab-text]'))
+        ->toBe([
+            'display' => '-webkit-box',
+            'min-width' => '0',
+            'overflow' => 'hidden',
+            '-webkit-box-orient' => 'vertical',
+            '-webkit-line-clamp' => '2',
+            'text-align' => 'center',
+            'text-overflow' => 'ellipsis',
+            'white-space' => 'normal',
+        ])
+        // The ring's room and the state layer still reach past a grown tab to the divider.
+        ->and($css->declarations('[data-md-tab]::before'))
+        ->toHaveKey('inset-block', 'calc(-1 * var(--tabs-ring))')
+        ->and($css->declarations('[data-md-tab-indicator]'))
+        ->toHaveKey('bottom', 'calc(-1 * var(--tabs-ring))')
+        ->and(collect($css->rules())->filter(fn (array $rule): bool => str_contains($rule['selector'], 'data-md-tab-text'))->pluck('selector')->all())
+        ->toBe(['[data-md-tabs-bar]:not([data-md-scrollable]) [data-md-tab-text]']);
+});
+
 it('hides every panel until Alpine takes over, and stands the panel\'s content clear of the bar', function () {
     $css = ComponentStylesheet::read('tabs');
 
@@ -171,7 +221,9 @@ it('marks the section whose url is the request\'s, and scrolls many sections', f
         // Five or more sections are M3's scrollable tabs, not a grid of wrapped rows (N-16).
         ->toMatch('/<ul data-md-tabs-bar data-md-variant="secondary"\s+data-md-scrollable\s*>/')
         ->not->toContain('grid-cols-')
-        ->toMatch('/data-md-tab\s+aria-current="page"\s*>\s*<span data-md-tab-content>\s*<span class="md-truncate">S3/')
+        // Its label is `<x-tabs>`'s anatomy, drawn by tabs.css, not a one-line `md-truncate`.
+        ->toMatch('/data-md-tab\s+aria-current="page"\s*>\s*<span data-md-tab-content>\s*<span data-md-tab-label>\s*<span data-md-tab-text>S3<\/span>/')
+        ->not->toMatch('/data-md-tab-content>(?:(?!<\/a>).)*md-truncate/s')
         ->not->toContain('wire:navigate')
         // Four still share the row.
         ->and((string) $this->blade('<x-section-nav :items="$items" no-wire-navigate />', ['items' => array_slice($items, 0, 4)]))