原文地址：https://segmentfault.com/a/1190000015295466
感想：重点在小球绕环转动。
HTML code：
<div class="container">
<div class="ring"></div>
<div class="spheres">
<span class="sphere"></span>
<span class="sphere"></span>
<span class="sphere"></span>
</div>
</div>
CSS code：
html, body {
margin:;
padding:;
}
body {
height: 100vh;
display: flex;
justify-content: center;
align-items: center;
background-color: darkslategray;
}
/* 改变盒模型 为元素设定的宽度和高度包括了外内外边距 */
*{
box-sizing: border-box;
}
/* 画出圆环 */
.container{
position: relative;
font-size: 20px;
/* 最后，让容器转动起来，制造小球围绕圆环盘旋的效果 */
animation: rotate 5s linear infinite;
}
.ring{
position: relative;
width: 10em;
height: 10em;
border: 1.5em solid paleturquoise;
border-radius: 50%;
z-index:;
}
/* 在圆环的左上方画出一个小球 */
.sphere{
position: absolute;
top: -20%;
left: -20%;
/* 让小球盘旋 */
width: 80%;
height: 80%;
animation:
rotate 1.5s linear infinite,
overlapping 1.5s linear infinite;
}
/* 通过设置动画延时，制造 3 个小球同时盘旋的效果 */
.sphere:nth-child(2){
animation-delay: -0.5s;
}
.sphere:nth-child(3) {
animation-delay: -1s;
}
@keyframes rotate{
to{
transform: rotate(360deg);
}
}
/* 让小球的圆环的上下穿梭 */
@keyframes overlapping {
to {
z-index:;
}
}
.sphere::after{
content: '';
position: absolute;
width: 3em;
height: 3em;
border-radius: 50%;
background-color: lightseagreen;
}