<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>斜线布局</title>
<style>
.x {
border: solid 1px red;
width: 100px;
height: 100px;
position: relative;
background-color: transparent;
}
.x:before {
position: absolute;
top: 0px;
right: 0;
left: 0;
bottom: 0;
border-bottom: 100px solid red;
border-left: 100px solid transparent;
content: "";
}
.x:after {
position: absolute;
left: 1px;
right: 0;
top: 1px;
bottom: 0;
border-bottom: 99px solid white;
border-left: 99px solid transparent;
content: "";
}
.f {
border: solid 1px red;
width: 100px;
height: 100px;
position: relative;
background-color: transparent;
}
.f:before {
position: absolute;
top: 0px;
right: 0;
left: 0;
bottom: 0;
border-bottom: 100px solid red;
border-right: 100px solid transparent;
content: "";
}
.f:after {
position: absolute;
left: 0;
right: 1px;
top: 1px;
bottom: 0;
border-bottom: 99px solid white;
border-right: 99px solid transparent;
content: "";
}
</style>
</head>
<body>
<div class="x"> </div>
</body>
</html>