边框的常用属性
<!DOCTYPE html>
<html>
<head>
<title>边框练习</title>
<meta charset="UTF-8">
<link rel="shortuct icon" type="image/x-icon" href="static/1.jpg">
<link rel="stylesheet" type="text/css" href="static/css/index.css">
<style>
<!--solid=实线，double=双实线，dashed=方虚线，dotted=圆虚线-->
<!--border-radius=边框圆角-->
<!--border-shadow=边框阴影 border-shadow: x轴 y轴 阴影宽度 颜色 inset=内阴影-->
#one{width:500px;height:500px;border:1px solid red;border-radius:10px;border-shadow:0px 5px 5px #ccc inset}
<!--清除边框线-->
button{border:none}
</style>
</head>
<body>
<div id="one"></div>
<button>登录</button>
</body>
</html>