css3新增UI样式

圆角border-radius

border-radius:1-4个数字/1-4个数字

前面是水平，后面是垂直

不给”/“,则水平和垂直一样 border-radius:10px/5px

参数：各种长度单位都可以：px,%, %有时候很方便，但是宽高不一致时不太好

<!DOCTYPE HTML>
<html>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>无标题文档</title>
    <style>
    .box {
        width: 400px;
        height: 400px;
        margin: 50px auto;
        transition: 5s linear;
    }

    .box div {
        width: 180px;
        height: 180px;
        margin: 10px;
        border: 1px solid #000;
        box-sizing: border-box;
        float: left;
        background: url(new_bg.png) no-repeat;
    }

    .box div:nth-child(1),
    .box div:nth-child(4) {
        border-radius: 0 70%;
    }

    .box div:nth-child(2),
    .box div:nth-child(3) {
        border-radius: 70% 0;
    }

    .box:hover {
        -webkit-transform: rotate(720deg);
    }
    </style>
</head>

<body>
    <div class="box">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
</body>

</html>