console
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>《beats耳机》按钮</title>
<style>
*{
margin: 0;
padding: 0
}
.main{
position: relative;
width: 150px;
height: 50px;
margin: 100px auto;
color: #000
}
a{
display: inline-block;
width: 100%;
height: 100%;
text-decoration: none;
border: 1px solid #ccc;
text-align: center;
line-height: 50px;
transition: all 0.5s linear;
-webkit-transition: all 0.5s linear;
}
.a-div{
position: absolute;
left: 0;
bottom: 0;
width: 100%;
height: 0;
background-color: #eee;
opacity: 0;
transition: all 0.5s linear;
-webkit-transition: all 0.5s linear;
}
.main:hover a{
color: #fff
}
.main:hover .a-div{
height: 50px;
opacity: 0.7;
}
</style>
</head>
<body>
<div class="main">
<a href="#">按钮</a>
<div class="a-div"></div>
</div>
</body>
</html>