动画.gif
控制background的颜色大小和位置来做过渡效果。
<!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>
<style>
.title {
color: #333;
line-height: 2px;
text-align: center;
}
.title span {
background: linear-gradient(to right, red, blue) no-repeat right bottom;
background-size: 0 2px;
transition: background-size 1300ms;
}
.title span:hover {
background-position-x: left;
background-size: 100% 2px;
}
</style>
</head>
<body>
<h2 class="title">
<span>下划线hover过渡效果</span>
</h2>
</body>
</html>
