Draw the split button without Tailwind

Plan step 36. <x-split-button> renders data-md-split-button and
data-md-size on the pair and data-md-split on its halves. split-button.css
draws SplitButton*Tokens' shape — full outer corners, inner corners that
grow under the finger, the trailing half round while its menu is open —
the narrower leading padding and 48px trailing half at xs and sm, and the
chevron's own size, nudge and turn on the standard scheme. groups.css is
empty and leaves tailwind.css.

The actions browser test follows data-md-split and data-md-button-group,
and gains the owed tests for a connected segment's 48px edge and a
button group's single-required and multi selection.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

resources/css/components.css

@@ -18,6 +18,7 @@
 @import './components/button.css';
 @import './components/group.css';
 @import './components/button-group.css';
+@import './components/split-button.css';
 
 /* Inputs, selection and data */
 

resources/css/components/groups.css

@@ -1,81 +0,0 @@
-/*
- * Split buttons: shapes that depend on a button's place beside its other half. Button groups and
- * `<x-group>` draw theirs from resources/css/components/button-group.css.
- *
- * Unlayered on purpose, until the split button leaves Tailwind too.
- *
- * Split button (`<x-split-button>`): two halves on their own corner scale — SplitButton*Tokens
- * gives the inner corner 4/4/4/8/12px at rest and *grows* it to 8/12/12/20/20px under the finger,
- * the opposite of a connected group. The trailing half turns round and its chevron turns over
- * while its menu is open, on M3's standard scheme rather than the expressive springs (the site:
- * "the trailing button uses the standard motion scheme, not expressive, when rotating"), and the
- * chevron sits a little towards the leading half so the pair reads as one control
- * (`--split-nudge`: 1/1/2/3/6px). `--split-icon` is the trailing icon's own size,
- * 22/22/26/38/50px, which the icon-button table does not know about.
- *
- * "Full" here is half the size's height (`--group-full`), never `--md-sys-shape-corner-full`'s
- * 9999px: when a box's radii add up to more than its side, CSS scales every radius by the same
- * factor, and a 9999px corner beside an 8px one drew the inner corners square.
- */
-
-[data-button-group] {
-    --group-full: 1.25rem;
-    --group-outer: var(--group-full);
-}
-
-[data-button-group][data-size='xs'] { --group-full: 1rem; }
-[data-button-group][data-size='md'] { --group-full: 1.75rem; }
-[data-button-group][data-size='lg'] { --group-full: 3rem; }
-[data-button-group][data-size='xl'] { --group-full: 4.25rem; }
-
-[data-button-group='split'] { --split-inner: var(--md-sys-shape-corner-xs); --split-inner-pressed: var(--md-sys-shape-corner-md); --split-icon: 22px; --split-nudge: 1px; }
-[data-button-group='split'][data-size='xs'] { --split-inner-pressed: var(--md-sys-shape-corner-sm); }
-[data-button-group='split'][data-size='md'] { --split-icon: 26px; --split-nudge: 2px; }
-[data-button-group='split'][data-size='lg'] { --split-inner: var(--md-sys-shape-corner-sm); --split-inner-pressed: var(--md-sys-shape-corner-lg-increased); --split-icon: 38px; --split-nudge: 3px; }
-[data-button-group='split'][data-size='xl'] { --split-inner: var(--md-sys-shape-corner-md); --split-inner-pressed: var(--md-sys-shape-corner-lg-increased); --split-icon: 50px; --split-nudge: 6px; }
-
-/* The halves take their inner corner from `--group-corner`, so pressing changes one variable and
-   the rounded outer corners stay put. */
-[data-split] {
-    --group-corner: var(--split-inner);
-
-    border-start-start-radius: var(--group-corner);
-    border-end-start-radius: var(--group-corner);
-    border-start-end-radius: var(--group-corner);
-    border-end-end-radius: var(--group-corner);
-}
-
-[data-split]:active {
-    --group-corner: var(--split-inner-pressed);
-}
-
-[data-split='trailing'][aria-expanded='true'] {
-    --group-corner: var(--group-full);
-}
-
-[data-split='leading'] {
-    border-start-start-radius: var(--group-outer);
-    border-end-start-radius: var(--group-outer);
-}
-
-[data-split='trailing'] {
-    border-start-end-radius: var(--group-outer);
-    border-end-end-radius: var(--group-outer);
-}
-
-/*
- * The trailing chevron: its own size, and `--split-nudge` off centre towards the leading half —
- * equal and opposite margins move it by exactly that much inside a centred flex row, in whichever
- * direction the writing mode runs.
- */
-[data-split='trailing'] svg {
-    width: var(--split-icon);
-    height: var(--split-icon);
-    margin-inline-start: calc(-1 * var(--split-nudge));
-    margin-inline-end: var(--split-nudge);
-    transition: rotate var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard);
-}
-
-[data-split='trailing'][aria-expanded='true'] svg {
-    rotate: 180deg;
-}

resources/css/components/split-button.css

@@ -0,0 +1,115 @@
+/*
+ * <x-split-button>: an action and a menu of its alternatives, as two `<x-button>`s 2px apart.
+ *
+ * The halves share one shape (SplitButtonXSmall…XLargeTokens, androidx Compose Material 3,
+ * Apache-2.0): outer corners full — half the height, 16/20/28/48/68px, never 9999px, which would
+ * scale the small inner corners away — and inner corners of 4/4/4/8/12px that *grow* under the
+ * finger to 8/12/12/20/20px, the opposite of a connected button group. The trailing half turns
+ * fully round while its menu is open (`aria-expanded`). `<x-button>`'s own corner rules carry no
+ * specificity, so these win.
+ *
+ * At the two smallest sizes the leading half keeps less room on its inner side (10px at `xs`,
+ * 12px at `sm`) and the trailing half is 48px wide. The trailing chevron has its own size,
+ * 22/22/26/38/50px, which the icon-button table does not know about, and sits
+ * `--md-split-button-nudge` (1/1/2/3/6px) towards the leading half so the pair reads as one
+ * control: equal and opposite inline margins move it by exactly that much inside a centred flex
+ * row, in whichever direction the writing mode runs. It turns over while the menu is open, on M3's
+ * standard scheme rather than the expressive springs (the site: "the trailing button uses the
+ * standard motion scheme, not expressive, when rotating").
+ */
+
+@layer material.reset, material.tokens, material.base, material.layout, material.components, material.text, material.visibility;
+
+@import './button.css';
+
+@layer material.components {
+    [data-md-split-button] {
+        --md-split-button-inner: var(--md-sys-shape-corner-xs);
+        --md-split-button-inner-pressed: var(--md-sys-shape-corner-md);
+        --md-split-button-full: 20px;
+        --md-split-button-icon: 22px;
+        --md-split-button-nudge: 1px;
+
+        display: inline-flex;
+        align-items: center;
+        gap: var(--md-sys-measurement-space25);
+    }
+
+    [data-md-split-button][data-md-size='xs'] {
+        --md-split-button-inner-pressed: var(--md-sys-shape-corner-sm);
+        --md-split-button-full: 16px;
+    }
+
+    [data-md-split-button][data-md-size='md'] {
+        --md-split-button-full: 28px;
+        --md-split-button-icon: 26px;
+        --md-split-button-nudge: 2px;
+    }
+
+    [data-md-split-button][data-md-size='lg'] {
+        --md-split-button-inner: var(--md-sys-shape-corner-sm);
+        --md-split-button-inner-pressed: var(--md-sys-shape-corner-lg-increased);
+        --md-split-button-full: 48px;
+        --md-split-button-icon: 38px;
+        --md-split-button-nudge: 3px;
+    }
+
+    [data-md-split-button][data-md-size='xl'] {
+        --md-split-button-inner: var(--md-sys-shape-corner-md);
+        --md-split-button-inner-pressed: var(--md-sys-shape-corner-lg-increased);
+        --md-split-button-full: 68px;
+        --md-split-button-icon: 50px;
+        --md-split-button-nudge: 6px;
+    }
+
+    [data-md-split-button] [data-md-split] {
+        --md-split-button-corner: var(--md-split-button-inner);
+
+        border-start-start-radius: var(--md-split-button-corner);
+        border-end-start-radius: var(--md-split-button-corner);
+        border-start-end-radius: var(--md-split-button-corner);
+        border-end-end-radius: var(--md-split-button-corner);
+    }
+
+    [data-md-split-button] [data-md-split]:active {
+        --md-split-button-corner: var(--md-split-button-inner-pressed);
+    }
+
+    [data-md-split-button] [data-md-split='trailing'][aria-expanded='true'] {
+        --md-split-button-corner: var(--md-split-button-full);
+    }
+
+    [data-md-split-button] [data-md-split='leading'] {
+        border-start-start-radius: var(--md-split-button-full);
+        border-end-start-radius: var(--md-split-button-full);
+    }
+
+    [data-md-split-button] [data-md-split='trailing'] {
+        border-start-end-radius: var(--md-split-button-full);
+        border-end-end-radius: var(--md-split-button-full);
+    }
+
+    [data-md-split-button][data-md-size='xs'] [data-md-split='leading'] {
+        padding-inline-end: var(--md-sys-measurement-space125);
+    }
+
+    [data-md-split-button][data-md-size='sm'] [data-md-split='leading'] {
+        padding-inline-end: 12px;
+    }
+
+    [data-md-split-button]:is([data-md-size='xs'], [data-md-size='sm']) [data-md-split='trailing'] {
+        inline-size: var(--md-sys-measurement-space600);
+    }
+
+    [data-md-split-button] [data-md-split='trailing'] [data-md-icon] {
+        inline-size: var(--md-split-button-icon);
+        block-size: var(--md-split-button-icon);
+        margin-inline-start: calc(-1 * var(--md-split-button-nudge));
+        margin-inline-end: var(--md-split-button-nudge);
+        transition: rotate var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard);
+    }
+
+    [data-md-split-button] [data-md-split='trailing'][aria-expanded='true'] [data-md-icon] {
+        rotate: 180deg;
+    }
+}

resources/css/tailwind.css

@@ -18,7 +18,6 @@
 @import './tokens/utilities.css';
 /* Actions and communication — leaving in step 36 */
 @import './components/actions.css';
-@import './components/groups.css';
 @import './components/menu.css';
 
 /* Inputs, selection and data — leaving in step 36 */

resources/views/components/split-button.blade.php

@@ -5,16 +5,16 @@
              <x-menu-item label="Download files one by one" wire:click="downloadEach" />
          </x-split-button>
 
-     Attributes (wire:click, spinner…) go to the leading button; the slot is the menu. `variant` is
-     `filled` (the default), `tonal`, `outlined` or `elevated` — a text split button does not exist
-     in M3 — with `color` and `size` as on `<x-button>`. The halves sit 2px apart; the trailing
-     one rounds fully and turns its chevron over while the menu is open. `menu-label` names the
-     trailing button and the menu for screen readers.
+     Attributes (wire:click, spinner…) go to the leading button, a `class` to the pair; the slot is
+     the menu. `variant` is `filled` (the default), `tonal`, `outlined` or `elevated` — a text split
+     button does not exist in M3 — with `color` and `size` as on `<x-button>`. The halves sit 2px
+     apart; the trailing one rounds fully and turns its chevron over while the menu is open.
+     `menu-label` names the trailing button and the menu for screen readers.
 
      Padding from SplitButton*Tokens (androidx Compose Material 3, Apache-2.0): the leading button
      keeps less room on its inner side at the two smallest sizes, and the trailing button is 48px
-     wide there. resources/css/components/groups.css carries the rest of the spec, which is all
-     geometry: the inner corners (4/4/4/8/12px, growing under the finger, not shrinking as a
+     wide there. resources/css/components/split-button.css carries the rest of the spec, which is
+     all geometry: the inner corners (4/4/4/8/12px, growing under the finger, not shrinking as a
      connected group's do), the trailing icon's own size (22/22/26/38/50px, which the icon-button
      table has no entry for), the 1/1/2/3/6px nudge that sits the chevron towards the leading half,
      and the standard motion scheme M3 asks for while it turns over. --}}
@@ -35,12 +35,9 @@
     $variant = in_array($variant, ['filled', 'tonal', 'outlined', 'elevated'], true) ? $variant : 'filled';
     $size = in_array($size, ['xs', 'sm', 'md', 'lg', 'xl'], true) ? $size : 'sm';
     $menuLabel ??= __('More options');
-
-    $leadingPadding = ['xs' => 'pe-2.5', 'sm' => 'pe-3', 'md' => '', 'lg' => '', 'xl' => ''][$size];
-    $trailingWidth = ['xs' => 'w-12', 'sm' => 'w-12', 'md' => '', 'lg' => '', 'xl' => ''][$size];
 @endphp
 
-<div data-button-group="split" data-size="{{ $size }}" {{ $attributes->only('class')->class('inline-flex items-center gap-0.5') }}>
+<div data-md-split-button data-md-size="{{ $size }}" {{ $attributes->only('class') }}>
     <x-livewire-material::button
         {{ $attributes->except('class') }}
         :label="$label"
@@ -50,8 +47,7 @@
         :size="$size"
         :disabled="$disabled"
         :spinner="$spinner"
-        data-split="leading"
-        :class="$leadingPadding"
+        data-md-split="leading"
     />
 
     <x-livewire-material::menu :position="$position" :label="$menuLabel">
@@ -63,8 +59,7 @@
                 :color="$color"
                 :size="$size"
                 :disabled="$disabled"
-                data-split="trailing"
-                :class="$trailingWidth"
+                data-md-split="trailing"
             />
         </x-slot:trigger>