<!DOCTYPE html>
<html lang="zh">
<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 type="text/css">
/*箭頭向上*/
.arrow-up {
width: 0;
height: 0;
border-left: 30px solid transparent;
border-right: 30px solid transparent;
border-bottom: 30px solid #fea;
}
/*箭頭向下*/
.arrow-down {
width: 0;
height: 0;
border-left: 20px solid transparent;
border-right: 20px solid transparent;
border-top: 20px solid #0066cc;
}
/*箭頭向左*/
.arrow-left {
width: 0;
height: 0;
border-top: 30px solid transparent;
border-bottom: 30px solid transparent;
border-right: 30px solid yellow;
}
/*箭頭向右*/
.arrow-right {
width: 0;
height: 0;
border-top: 50px solid transparent;
border-bottom: 50px solid transparent;
border-left: 50px solid green;
}
</style>
</head>
<body>
<div class="arrow-up">
<!--向上的三角-->
</div>
<div class="arrow-down">
<!--向下的三角-->
</div>
<div class="arrow-left">
<!--向左的三角-->
</div>
<div class="arrow-right">
<!--向右的三角-->
</div>
</body>
</html>
