前端每日实战：21# 视频演示如何用纯 CSS 创作文本滑动特效的 UI 界面

效果预览

按下右侧的“点击预览”按钮可以在当前页面预览，点击链接可以全屏预览。

https://codepen.io/comehope/pen/QrxxaW

可交互视频教程

此视频是可以交互的，你可以随时暂停视频，编辑视频中的代码。

请用 chrome, safari, edge 打开观看。

https://scrimba.com/p/pEgDAM/cgRgQHr

源代码下载

请从 github 下载。

https://github.com/comehope/front-end-daily-challenges/tree/master/021-a-text-sliding-effect-ui

代码解读

定义 dom，容器中包含 question 和 answer：

<div>
    <p>
        <span class="question">Who gives you milk?</span>
        <span class="answer">cow</span>
    </p>
</div>

居中显示：

html, body {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: darkcyan;
}

设置文本样式：

p {
    width: 400px;
    height: 2.5em;
    color: gold;
    font-size: 24px;
    border: 2px solid gold;
    line-height: 2.5em;
    text-align: center;
    border-radius: 10px;
    font-family: sans-serif;
    letter-spacing: 2px;
    word-spacing: 2px;
    box-shadow: 5px 5px 10px rgba(0, 0, 0, 0.2);
}

设置答案的样式：

p {
    position: relative;
}
p span {
    position: absolute;
    width: 100%;
    top: 0;
    left: 0;
}
p .answer {
    color: whitesmoke;
    font-size: 1.1em;
    text-transform: uppercase;
    background: rgba(0, 0, 0, 0.1);
}

增加问题与答案滑动切换的动画效果：

p {
    overflow: hidden;
}
p span {
    transition: 0.5s ease-out;
}
p .question {
    left: 0;
}
p:hover .question {
    left: 100%;
}
p .answer {
    left: -100%;
}
p:hover .answer {
    left: 0;
}

dom 中再增加 2 个问题：

<div>
    <p>
        <span class="question">Who gives you milk?</span>
        <span class="answer">cow</span>
    </p>
    <p>
        <span class="question">Who likes to eat flies?</span>
        <span class="answer">frog</span>
    </p>
    <p>
        <span class="question">Who have large claws?</span>
        <span class="answer">crab</span>
    </p>
</div>

dom 中增加标题：

<div>
    <h1>Who Am I</h1>
    <p>
        <span class="question">Who gives you milk?</span>
        <span class="answer">cow</span>
    </p>
    <p>
        <span class="question">Who likes to eat flies?</span>
        <span class="answer">frog</span>
    </p>
    <p>
        <span class="question">Who have large claws?</span>
        <span class="answer">crab</span>
    </p>
</div>

设置标题样式：

h1 {
    font-family: sans-serif;
    color: gold;
    text-align: center;
}

最后，用伪元素增加大问号作为装饰背景：

h1 {
    position: relative;
}
h1::after {
    content: '?';
    position: absolute;
    top: -0.35em;
    left: 0;
    font-size: 25em;
    transform: rotate(15deg);
    color: cyan;
    filter: opacity(0.3);
    text-shadow: 10px 10px 10px rgba(0, 0, 0, 0.2);
}

知识点

• rotate() https://developer.mozilla.org/en-US/docs/Web/CSS/transform-function/rotate
• filter https://developer.mozilla.org/en-US/docs/Web/CSS/filter
• transition https://developer.mozilla.org/en-US/docs/Web/CSS/transition