要创建看起来像彩虹色的线性渐变，您可以尝试运行以下代码\
<!DOCTYPE html>
<html>
<head>
<style>
#demo {
height: 100px;
background: linear-gradient(to right, red,orange,yellow,green,blue,indigo,violet);
}
</style>
</head>
<body>
<h2>Linear Gradient</h2>
<div id = "demo">Rainbow</div><br>
</body>
</html>