<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
div.left {
float: left;
}
div.arr-t {
width: 0;
height: 0;
border-width:10px;
border-style: solid dashed dashed dashed;
/* 上 右 下 左 */
border-color: red transparent transparent transparent;
}
div.arr-r {
width: 0;
height: 0;
border-width: 10px;
border-style: dashed solid dashed dashed;
border-color:transparent pink transparent transparent;
}
div.arr-l {
width: 0;
height: 0;
border-width: 10px;
border-style: dashed dashed dashed solid;
border-color:transparent transparent transparent blue;
}
div.arr-b {
width: 0;
height: 0;
border-width: 10px;
border-style: dashed dashed solid dashed ;
border-color:transparent yellow transparent transparent;
}
</style>
</head>
<body>
<div class="left">
<div class="arr-t"></div>
<div class="arr-r"></div>
<div class="arr-l"></div>
<div class="arr-b"></div>
</div>
</body>
</html>
