如何使用纯CSS实现抽象的水波荡漾的动画（附源码）

效果预览

源代码下载

https://github.com/comehope/front-end-daily-challenges

代码解读

定义 dom，容器中包含 9 个元素：

<div class="container">
 <span></span>
 <span></span>
 <span></span>
 <span></span>
 <span></span>
 <span></span>
 <span></span>
 <span></span>
 <span></span>
</div>

居中显示：

body {
 margin: 0;
 height: 100vh;
 display: flex;
 align-items: center;
 justify-content: center;
 background-color: black;
}

定义容器尺寸：

.container {
 width: 30em;
 height: 30em;
 font-size: 10px;
}

用 grid 布局把 9 个子元素排列成 3 * 3 的网格状：

.container {
 display: grid;
 grid-template-columns: repeat(3, 1fr);
}

设置容器内子元素的样式，是通过伪元素来设置的：

.container span {
 position: relative;
}

.container span::before,
.container span::after 
{
 content: '';
 position: absolute;
 box-sizing: border-box;
 border-style: none solid solid none;
 border-width: 1em;
 border-color: gold;
 width: 100%;
 height: 100%;
}

旋转容器，让它的尖端朝上：

.container {
 transform: rotate(-135deg);
}

增加子元素尺寸由小到大变化的动画：

.container span::before,
.container span::after 
{
 animation: 
 animate-scale 1.6s linear infinite;
}

@keyframes animate-scale {
 from {
 width: 1%;
 height: 1%;
 }

 to {
 width: 100%;
 height: 100%;
 }
}

增加子元素边框色变化的动画：

.container span::before,
.container span::after 
{
 animation: 
 animate-border-color 1.6s linear infinite,
 animate-scale 1.6s linear infinite;
}

@keyframes animate-border-color {
 0%, 25% {
 border-color: tomato;
 }

 50%, 75% {
 border-color: gold;
 }

 100% {
 border-color: black;
 }
}

增加子元素边框宽度变化的动画：

.container span::before,
.container span::after 
{
 animation: 
 animate-border-width 1.6s linear infinite,
 animate-border-color 1.6s linear infinite,
 animate-scale 1.6s linear infinite;
}

最后，让 ::after 伪元素的动画时间慢半拍：

.container span::after {
 animation-delay: -0.8s;
}

@keyframes animate-border-width {
 0%, 100%{
 border-width: 0.1em;
 }

 25% {
 border-width: 1.5em;
 }
}

大功告成！