freeCodeCamp/curriculum/challenges/chinese-traditional/01-responsive-web-design/basic-css/style-multiple-elements-with-a-css-class.md

---
id: bad87fee1348bd9aefe08806
title: 使用 class 選擇器設置多個元素的樣式
challengeType: 0
videoUrl: 'https://scrimba.com/c/cRkVbsQ'
forumTopicId: 18311
dashedName: style-multiple-elements-with-a-css-class
---

# --description--

通過 CSS class 選擇器，多個 HTML 元素可以使用相同的 CSS 樣式規則。 你可以將 `red-text` class 添加到第一個 `p` 元素上。

# --hints--

`h2` 元素應該是紅色的。

```js
assert($('h2').css('color') === 'rgb(255, 0, 0)');
```

`h2` 元素應含有 `red-text` class。

```js
assert($('h2').hasClass('red-text'));
```

第一個 `p` 元素應爲紅色。

```js
assert($('p:eq(0)').css('color') === 'rgb(255, 0, 0)');
```

第二和第三個 `p` 元素不應爲紅色。

```js
assert(
  !($('p:eq(1)').css('color') === 'rgb(255, 0, 0)') &&
    !($('p:eq(2)').css('color') === 'rgb(255, 0, 0)')
);
```

第一個 `p` 元素應該包含 `red-text` class。

```js
assert($('p:eq(0)').hasClass('red-text'));
```

# --seed--

## --seed-contents--

```html
<style>
  .red-text {
    color: red;
  }
</style>

<h2 class="red-text">CatPhotoApp</h2>
<main>
  <p>Click here to view more <a href="#">cat photos</a>.</p>

  <a href="#"><img src="https://cdn.freecodecamp.org/curriculum/cat-photo-app/relaxing-cat.jpg" alt="A cute orange cat lying on its back."></a>

  <div>
    <p>Things cats love:</p>
    <ul>
      <li>cat nip</li>
      <li>laser pointers</li>
      <li>lasagna</li>
    </ul>
    <p>Top 3 things cats hate:</p>
    <ol>
      <li>flea treatment</li>
      <li>thunder</li>
      <li>other cats</li>
    </ol>
  </div>

  <form action="https://freecatphotoapp.com/submit-cat-photo">
    <label><input type="radio" name="indoor-outdoor" checked> Indoor</label>
    <label><input type="radio" name="indoor-outdoor"> Outdoor</label><br>
    <label><input type="checkbox" name="personality" checked> Loving</label>
    <label><input type="checkbox" name="personality"> Lazy</label>
    <label><input type="checkbox" name="personality"> Energetic</label><br>
    <input type="text" placeholder="cat photo URL" required>
    <button type="submit">Submit</button>
  </form>
</main>
```

# --solutions--

```html
<style>
  .red-text {
    color: red;
  }
</style>

<h2 class="red-text">CatPhotoApp</h2>
<main>
  <p class="red-text">Click here to view more <a href="#">cat photos</a>.</p>

  <a href="#"><img src="https://cdn.freecodecamp.org/curriculum/cat-photo-app/relaxing-cat.jpg" alt="A cute orange cat lying on its back."></a>

  <div>
    <p>Things cats love:</p>
    <ul>
      <li>cat nip</li>
      <li>laser pointers</li>
      <li>lasagna</li>
    </ul>
    <p>Top 3 things cats hate:</p>
    <ol>
      <li>flea treatment</li>
      <li>thunder</li>
      <li>other cats</li>
    </ol>
  </div>

  <form action="https://freecatphotoapp.com/submit-cat-photo">
    <label><input type="radio" name="indoor-outdoor" checked> Indoor</label>
    <label><input type="radio" name="indoor-outdoor"> Outdoor</label><br>
    <label><input type="checkbox" name="personality" checked> Loving</label>
    <label><input type="checkbox" name="personality"> Lazy</label>
    <label><input type="checkbox" name="personality"> Energetic</label><br>
    <input type="text" placeholder="cat photo URL" required>
    <button type="submit">Submit</button>
  </form>
</main>
```