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Tailwind CSS Academy · レッスン

Headless Menu とドロップダウンのスタイリング

Headless UI の Menu コンポーネントに Tailwind のユーティリティクラスを適用し、キーボード操作と ARIA 属性に対応した洗練されたドロップダウンを作成します。

「Headless Menu とドロップダウンのスタイリング」はCoddyKit上の無料Tailwind CSS Academyレッスンです。 これはレッスン2/4です。 下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。 これはTailwind CSS Academy学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 Tailwind CSS Academyコースには全4レッスンが含まれています。

このレッスンの一部はまだ翻訳されておらず、英語で表示されています。

Anatomy of a Headless UI Menu

The Headless UI Menu is composed of four pieces: Menu (the root wrapper that provides context), Menu.Button (the clickable trigger), Menu.Items (the dropdown panel that shows when open), and one or more Menu.Item elements (individual selectable options). Each piece accepts className or a render function that receives state, giving you full Tailwind control at every level.

import { Menu } from '@headlessui/react';

// Structure overview
<Menu as='div' className='relative inline-block'>
  {/* 1. Trigger button */}
  <Menu.Button>Open</Menu.Button>

  {/* 2. Dropdown panel (shown when open) */}
  <Menu.Items>
    {/* 3. Individual options */}
    <Menu.Item>{({ active }) => <button>Option A</button>}</Menu.Item>
    <Menu.Item>{({ active }) => <button>Option B</button>}</Menu.Item>
  </Menu.Items>
</Menu>

Styling the Menu Trigger Button

The Menu.Button trigger should communicate interactivity and show its open/closed state visually. Access the open render prop to change the button's appearance when the dropdown is visible. Common patterns include rotating a chevron icon, changing the background color to match the open dropdown, and adding a ring for focus visibility.

import { Menu } from '@headlessui/react';
import { ChevronDownIcon } from '@heroicons/react/20/solid';

<Menu.Button className='inline-flex items-center gap-2 rounded-lg border border-gray-300 bg-white px-4 py-2 text-sm font-medium text-gray-700 shadow-sm hover:bg-gray-50 focus:outline-none focus:ring-2 focus:ring-blue-500'>
  {({ open }) => (
    <>
      Actions
      <ChevronDownIcon
        className={cn(
          'h-4 w-4 text-gray-400 transition-transform duration-150',
          open && 'rotate-180'
        )}
      />
    </>
  )}
</Menu.Button>

Positioning the Dropdown Panel

The Menu.Items panel should appear visually anchored below the trigger. Position the Menu root as relative and the panel as absolute. Use top-full and right-0 or left-0 to align the panel to the trigger. Set a z-index to ensure the dropdown appears above other page content, and add mt-1 for a small gap between trigger and panel.

<Menu as='div' className='relative'>
  <Menu.Button>...</Menu.Button>

  <Menu.Items
    className='
      absolute right-0 top-full mt-1 z-20
      w-56 origin-top-right
      rounded-xl bg-white shadow-lg
      ring-1 ring-black/5
      focus:outline-none
    '
  >
    {/* Items */}
  </Menu.Items>
</Menu>

Styling Menu Items With Active State

Each Menu.Item receives an active render prop that is true when the item is focused or hovered. Use this to apply a highlighted background — typically a subtle blue or gray. Also use disabled to dim and prevent interaction on unavailable options. Wrap the content in a button or a element to make it keyboard focusable.

<Menu.Items className='absolute right-0 mt-1 w-56 rounded-xl bg-white shadow-lg ring-1 ring-black/5 p-1'>

  <Menu.Item>
    {({ active }) => (
      <button
        className={cn(
          'flex w-full items-center gap-2 rounded-lg px-3 py-2 text-sm',
          active ? 'bg-blue-50 text-blue-700' : 'text-gray-700'
        )}
      >
        <PencilIcon className='h-4 w-4' />
        Edit
      </button>
    )}
  </Menu.Item>

  <Menu.Item disabled>
    {({ active, disabled }) => (
      <button
        className={cn(
          'flex w-full items-center gap-2 rounded-lg px-3 py-2 text-sm',
          disabled && 'opacity-40 cursor-not-allowed'
        )}
      >
        <ShareIcon className='h-4 w-4' />
        Share (unavailable)
      </button>
    )}
  </Menu.Item>
</Menu.Items>

Adding Dividers Between Groups

Group related menu items with visual dividers. Since Headless UI does not provide a divider component, simply insert a plain div with a border or a padding wrapper. Organize items into logical sections — primary actions, secondary actions, and a destructive action — separated by thin horizontal rules styled with Tailwind.

<Menu.Items className='absolute right-0 mt-1 w-56 rounded-xl bg-white shadow-lg ring-1 ring-black/5 p-1 focus:outline-none'>
  {/* Primary actions */}
  <div className='pb-1 border-b border-gray-100'>
    <Menu.Item>{({ active }) => <button className={itemCls(active)}>View</button>}</Menu.Item>
    <Menu.Item>{({ active }) => <button className={itemCls(active)}>Edit</button>}</Menu.Item>
  </div>

  {/* Secondary actions */}
  <div className='py-1 border-b border-gray-100'>
    <Menu.Item>{({ active }) => <button className={itemCls(active)}>Duplicate</button>}</Menu.Item>
  </div>

  {/* Destructive action */}
  <div className='pt-1'>
    <Menu.Item>
      {({ active }) => (
        <button className={cn('flex w-full px-3 py-2 text-sm rounded-lg', active ? 'bg-red-50 text-red-700' : 'text-red-600')}>
          Delete
        </button>
      )}
    </Menu.Item>
  </div>
</Menu.Items>

Dropdown With Icon Decorations

A polished dropdown includes icons alongside each label to help users quickly identify options. Import icons from a library like @heroicons/react (built by the same Tailwind Labs team) and place them as inline elements within menu item buttons. Use consistent icon sizing — h-4 w-4 for small menus — and softer colors that inherit the item's active state.

import {
  PencilSquareIcon,
  DocumentDuplicateIcon,
  TrashIcon
} from '@heroicons/react/20/solid';

const menuItems = [
  { label: 'Edit', icon: PencilSquareIcon, action: handleEdit },
  { label: 'Duplicate', icon: DocumentDuplicateIcon, action: handleDuplicate }
];

menuItems.map(({ label, icon: Icon, action }) => (
  <Menu.Item key={label}>
    {({ active }) => (
      <button
        onClick={action}
        className={cn(
          'flex w-full items-center gap-3 rounded-lg px-3 py-2 text-sm',
          active ? 'bg-blue-50 text-blue-700' : 'text-gray-700'
        )}
      >
        <Icon className='h-4 w-4 flex-shrink-0' />
        {label}
      </button>
    )}
  </Menu.Item>
))

Keyboard Navigation in Headless Menu

Headless UI's Menu implements full keyboard support automatically. Pressing Enter or Space on the button opens the menu. Arrow keys navigate between items. Home and End jump to the first and last items. Escape closes the menu and returns focus to the trigger. Tab closes the menu. These behaviors follow the ARIA menu button pattern and require no additional code from you.

/*
  Keyboard behavior (automatic with Headless UI):

  Trigger button:
  - Enter / Space → opens menu, focuses first item
  - ArrowDown → opens menu, focuses first item
  - ArrowUp → opens menu, focuses last item

  Inside menu:
  - ArrowDown → next item
  - ArrowUp → previous item
  - Home → first item
  - End → last item
  - Enter / Space → activates focused item
  - Escape → closes menu, returns focus to trigger
  - Tab → closes menu
  - Type a character → jump to first matching item
*/

Context Menu Pattern

A context menu (right-click menu) uses the same Menu structure but positions the panel relative to the cursor rather than the trigger button. Capture the right-click event, store the cursor position, and render the Menu.Items using fixed positioning at those coordinates. Headless UI still handles focus management and keyboard navigation inside the positioned menu.

function ContextMenuWrapper({ children }) {
  const [position, setPosition] = useState(null);

  const handleContextMenu = (e) => {
    e.preventDefault();
    setPosition({ x: e.clientX, y: e.clientY });
  };

  return (
    <div onContextMenu={handleContextMenu}>
      {children}
      {position && (
        <Menu>
          <Menu.Items
            static  // keep open without button
            style={{ top: position.y, left: position.x }}
            className='fixed z-50 w-48 rounded-xl bg-white shadow-xl ring-1 ring-black/5 p-1'
          >
            {/* menu items */}
          </Menu.Items>
        </Menu>
      )}
    </div>
  );
}

Popover vs Menu: When to Use Each

Headless UI provides both Menu and Popover components. Use Menu for action lists where each option performs an action or navigates. Use Popover for richer content panels — like a filter form, notification feed, or settings panel — where the content is not a simple list of actions and may contain interactive elements beyond buttons.

// Menu: for action lists
<Menu>
  <Menu.Button>Actions</Menu.Button>
  <Menu.Items>
    <Menu.Item>Edit</Menu.Item>     {/* action */}
    <Menu.Item>Delete</Menu.Item>   {/* action */}
  </Menu.Items>
</Menu>

// Popover: for rich content panels
import { Popover } from '@headlessui/react';

<Popover>
  <Popover.Button>Filters</Popover.Button>
  <Popover.Panel className='absolute z-10 mt-2 w-72 rounded-xl bg-white shadow-lg p-4'>
    {/* Rich content: form inputs, sliders, checkboxes */}
    <label>Price range</label>
    <input type='range' />
    <button>Apply filters</button>
  </Popover.Panel>
</Popover>

Mobile-Responsive Dropdown

On mobile, a traditional dropdown positioned absolutely can overflow the viewport edges. Apply responsive positioning to the Menu.Items panel: use right-0 on small screens and left-0 on larger ones, or switch to a bottom sheet pattern on mobile using Tailwind's sm: prefix. Test dropdowns at mobile viewport widths to ensure they remain fully visible and usable.

<Menu as='div' className='relative'>
  <Menu.Button>...</Menu.Button>

  <Menu.Items
    className='
      absolute z-20 mt-1 w-56
      rounded-xl bg-white shadow-lg ring-1 ring-black/5 p-1
      /* Mobile: right-aligned to avoid left-edge overflow */
      right-0
      /* Desktop: left-aligned for wider viewports */
      sm:right-auto sm:left-0
    '
  >
    {/* items */}
  </Menu.Items>
</Menu>

/* Also consider: on very small screens,
   render as a full-width bottom sheet instead */

Completing the Full Dropdown Component

Putting it all together: a complete, polished dropdown menu combines all the pieces — positioned container, styled trigger with chevron, grouped items with icons, dividers, and a destructive option. This component is reusable, fully keyboard navigable, and styled entirely with Tailwind — with zero custom CSS written and all accessibility handled by Headless UI.

export function ActionMenu({ onEdit, onDelete }) {
  return (
    <Menu as='div' className='relative'>
      <Menu.Button className='rounded-lg p-2 text-gray-500 hover:bg-gray-100 focus:ring-2 focus:ring-blue-500 focus:outline-none'>
        <EllipsisVerticalIcon className='h-5 w-5' />
      </Menu.Button>

      <Menu.Items className='absolute right-0 mt-1 w-48 rounded-xl bg-white shadow-lg ring-1 ring-black/5 p-1 focus:outline-none z-20'>
        <Menu.Item>
          {({ active }) => (
            <button onClick={onEdit} className={cn('w-full flex items-center gap-2 px-3 py-2 text-sm rounded-lg', active ? 'bg-gray-100' : 'text-gray-700')}>
              <PencilIcon className='h-4 w-4' />
              Edit
            </button>
          )}
        </Menu.Item>
        <div className='my-1 border-t border-gray-100' />
        <Menu.Item>
          {({ active }) => (
            <button onClick={onDelete} className={cn('w-full flex items-center gap-2 px-3 py-2 text-sm rounded-lg', active ? 'bg-red-50 text-red-700' : 'text-red-600')}>
              <TrashIcon className='h-4 w-4' />
              Delete
            </button>
          )}
        </Menu.Item>
      </Menu.Items>
    </Menu>
  );
}

Quick Check

Test your understanding of Tailwind CSS Mastery concepts from this lesson.

Lesson Recap

In this lesson you learned: Menu.Button triggers the dropdown with the open render prop for visual feedback, Menu.Items is positioned absolutely with Tailwind, and Menu.Item active drives the highlight style for the focused option. Next up we build fully accessible dialogs using Headless UI's Dialog component.

よくある質問

「Headless Menu とドロップダウンのスタイリング」レッスンは無料ですか？

はい。「Headless Menu とドロップダウンのスタイリング」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、Tailwind CSS Academyコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 Tailwind CSS Academyコースには全4レッスンが含まれています。

「Headless Menu とドロップダウンのスタイリング」で何を学びますか？

Headless UI の Menu コンポーネントに Tailwind のユーティリティクラスを適用し、キーボード操作と ARIA 属性に対応した洗練されたドロップダウンを作成します。 ブラウザで直接実行するハンズオンコードでTailwind CSS Academyを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。

Tailwind CSS Academyを始めるのに経験は必要ですか？

事前経験は必要ありません。CoddyKitのTailwind CSS Academyは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。 これはレッスン2/4です。

「Headless Menu とドロップダウンのスタイリング」レッスンにはどのくらい時間がかかりますか？

ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。

このTailwind CSS Academyレッスンでコードを書いて実行できますか？

はい。すべてのTailwind CSS Academyレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。

このコースのすべてのレッスン

  1. Headless UI 入門
  2. Headless Menu とドロップダウンのスタイリング
  3. アクセシブルなダイアログの構築
  4. Headless UI によるトランジション
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