利用伪元素,定位与过渡动画
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
li {
float: left;
list-style: none;
width: 78px;
position: relative;
height: 40px;
cursor: pointer;
text-align: center;
line-height: 40px;
transition: all .5s;
background: rgba(200, 200, 200, 1);
/* opacity: 1; */
}
a {
text-decoration: none;
}
a::before {
content: '';
position: absolute;
left: 50%;
right: 50%;
top: 0;
background: purple;
height: 4px;
transition: all .3s;
}
li:hover {
background: rgba(200, 200, 200, .6);
/* opacity: 0; */
}
li:hover a::before {
left: 0;
right: 0;
}
</style>
</head>
<body>
<ul>
<li><a href="">菜单1</a></li>
<li><a href="">菜单2</a></li>
<li><a href="">菜单3</a></li>
<li><a href="">菜单4</a></li>
<li><a href="">菜单5</a></li>
<li><a href="">菜单6</a></li>
<li><a href="">菜单7</a></li>
</ul>
</body>
</html>