```
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<h1>helloworld</h1>
<style>
* {
/* 初始化 取消頁面元素內外邊距 */
margin: 0;
padding: 0;
}
body {
background-color: #222;
/* 彈性布局 水平、垂直居中 */
display: flex;
justify-content: center;
align-items: center;
min-height: 100vh;
/* background: linear-gradient(200deg,#485563,#29323c); */
}
h1 {
color: #333;
text-transform: uppercase;
font-size: 112px;
position: relative;
}
h1::after {
content: "helloworld";
color: transparent;
position: absolute;
top: 0;
left: 0;
background: linear-gradient(to right, #FF69B3, #FE0000, #FFA401, #FFFF01, #008102, #40E1D2, #410098, #9400D4);
/* 以文字的范圍來裁剪背景圖片 */
background-clip: text;
-webkit-background-clip: text;
/* 將元素裁剪為一個圓形（100px表示圓的直徑，0% 50%表示圓心位置） */
clip-path: circle(100px at 0% 50%);
animation: light 5s infinite;
}
/* 定義動畫 改變圓心的位置 */
@keyframes light {
0% {
clip-path: circle(100px at 0% 50%);
}
50% {
clip-path: circle(100px at 100% 50%);
}
100% {
clip-path: circle(100px at 0% 50%);
}
}
</style>
<script>
</script>
</body>
</html>
```
