101 lines
2.2 KiB
Markdown
101 lines
2.2 KiB
Markdown
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---
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id: 587d78a8367417b2b2512ae5
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title: Animate Elements at Variable Rates
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challengeType: 0
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videoUrl: ''
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localeTitle: 以可变速率动画元素
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---
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## Description
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<section id="description">有多种方法可以改变类似动画元素的动画速率。到目前为止，这是通过应用<code>animation-iteration-count</code>属性和设置<code>@keyframes</code>规则来实现的。为了说明，右侧的动画由两个“星星”组成，每个“星星”的大小和不透明度在<code>@keyframes</code>规则中的20％标记处<code>@keyframes</code> ，从而创建闪烁动画。您可以更改其中一个元素的<code>@keyframes</code>规则，以便星星以不同的速率闪烁。 </section>
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## Instructions
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<section id="instructions">通过将其<code>@keyframes</code>规则更改为50％，更改类名为<code>star-1</code>的元素的动画速率。 </section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>star-1</code>类的<code>@keyframes</code>规则应为50％。
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testString: 'assert(code.match(/twinkle-1\s*?{\s*?50%/g), "The <code>@keyframes</code> rule for the <code>star-1</code> class should be 50%.");'
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='html-seed'>
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```html
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<style>
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.stars {
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background-color: white;
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height: 30px;
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width: 30px;
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border-radius: 50%;
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animation-iteration-count: infinite;
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}
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.star-1 {
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margin-top: 15%;
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margin-left: 60%;
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animation-name: twinkle-1;
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animation-duration: 1s;
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}
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.star-2 {
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margin-top: 25%;
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margin-left: 25%;
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animation-name: twinkle-2;
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animation-duration: 1s;
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}
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@keyframes twinkle-1 {
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20% {
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transform: scale(0.5);
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opacity: 0.5;
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}
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}
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@keyframes twinkle-2 {
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20% {
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transform: scale(0.5);
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opacity: 0.5;
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}
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}
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#back {
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position: fixed;
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padding: 0;
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margin: 0;
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top: 0;
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left: 0;
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width: 100%;
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height: 100%;
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background: linear-gradient(black, #000099, #66c2ff, #ffcccc, #ffeee6);
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}
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</style>
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<div id="back"></div>
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<div class="star-1 stars"></div>
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<div class="star-2 stars"></div>
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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</section>
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