<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<!-- border-style =边框线条
solid 实线
dashed 虚线
想要针对某一个单独位置设置边框颜色或大小等
如：border-left-style 中间可以填写任意方向
-->
<style>
div{
width: 500px;
height: 500px;
border-style: solid;
border-left-width: 10px;
border-color: chocolate;
border-left-style: blue;
}
</style>
</head>
<body>
<div></div>
</body>
</html>
#创建三角形
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
body{
background-color: green;
}
#div1{
width: 0px;
height: 0px;
border-top-style: solid;
border-top-width: 10px;
border-top-color: transparent;
border-right-style:solid;
border-right-width:10px;
border-right-color: transparent;
border-bottom-style:solid;
border-bottom-width: 10px;
border-bottom-color: blue;
border-left-style: solid;
border-left-width: 10px;
border-left-color: transparent;
}
</style>
</head>
<body>
<div id="div1"></div>
</body>
</html>