CSS 圆角边框

    <style type="text/css">
        body{padding: 20px;background-color: #FFF;
        font: 100.01% "Trebuchet MS",Verdana,Arial,sans-serif}
        h1,h2,p{margin: 0 10px}
        h1{font-size: 250%;color: #FFF}
        h2{font-size: 200%;color: #f0f0f0}
        p{padding-bottom:1em}
        h2{padding-top: 0.3em}
        div#nifty{ margin: 0 10%;background: #9BD1FA}
        b.rtop, b.rbottom{display:block;background: #FFF}
        b.rtop b, b.rbottom b{display:block;
        overflow: hidden; background: #9BD1FA}
        b.r1{margin: 0 5px}
        b.r2{margin: 0 3px}
        b.r3{margin: 0 2px}
        b.rtop b.r4, b.rbottom b.r4{margin: 0 1px;   </style>

    <b class="rbottom"><b class="r4"></b><b class="r3"></b>
    <b class="r2"></b><b class="r1"></b></b>
    </div>