随窗口大小而改变
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no" />
<title></title>
<style type="text/css">
*{
padding: 0;
margin: 0;
}
html{
font-size: calc(100vw/7.5);
}
.A{
font-size: 0.5rem;
width: 2rem;
height: 2rem;
text-align: center;
line-height: 2rem;
border: 1px solid red;
border-radius: 50%;
background-color: rgba(255,255,255,0.7);
margin: auto;
}
.B{
font-size: 16px;
width: 200px;
height: 200px;
text-align: center;
line-height: 200px;
border: 1px solid red;
border-radius: 50%;
background-color: rgba(255,255,255,0.7);
margin: auto;
}
</style>
</head>
<body>
<div class="A">rem</div>
<div class="B">rem</div>
</body>
</html>
