效果：
思路：使用伪元素，给伪元素设置背景色，然后定位，遮盖，旋转。就可以实现旋转边框效果。
实现代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta
name="viewport"
content="initial-scale=1.0, user-scalable=no, width=device-width"
/>
<title>document</title>
<style>
body {
background: #000;
}
button {
margin: 50px 40%;
width: 200px;
height: 80px;
color: #fff;
font-size: 24px;
background: #000;
border: none;
outline: none;
z-index: 1;
border-radius: 10px;
cursor: pointer;
position: relative;
overflow: hidden;
}
button::before {
content: "";
width: 200px;
height: 200px;
position: absolute;
background: orange;
z-index: -2;
left: 50%;
top: 50%;
transform-origin: left top;
animation: rotating 2s linear infinite;
}
button::after {
content: "";
position: absolute;
--g: 4px;
width: calc(100% - var(--g) * 2);
height: calc(100% - var(--g) * 2);
background: #000;
left: var(--g);
top: var(--g);
border-radius: inherit;
z-index: -1;
}
@keyframes rotating {
to {
transform: rotate(360deg);
}
}
</style>
</head>
<body>
<button>按钮</button>
<script></script>
</body>
</html>
