不同retina，显示高度不一样，很显然最细的线条最美
<!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>
*{
padding:0;
margin:0;
box-sizing: border-box;
}
.box{
100%;
height: 1px;
background: red;
margin-top: 50px;
}
@media (-webkit-min-device-pixel-ratio: 2){
.box2{
transform: scaleY(.5)
}
}
@media (-webkit-min-device-pixel-ratio: 3){
.box3{
transform: scaleY(.333)
}
}
@media (-webkit-min-device-pixel-ratio: 4){
.box4{
transform: scaleY(.1)
}
}
</style>
</head>
<body>
<div class="box"></div>
<div class="box box2"></div>
<div class="box box3"></div>
<div class="box box4"></div>
</body>
</html>
