CSS的div块各种边框

<div>方形框</div>
<div class="rounded">圆角形框</div>
<div class="asymmetric-radius">椭圆边形框</div>
<div class="asymmetric-corners">半圆形框</div>
<div class="percentages">圆形框</div>
<div class="sub-properties">单圆角形框</div>
<div class="brackets">小括号形框</div>
<div class="brackets"><span class="inner-brackets">双小括号形框</span></div>
<div class="squarebrackets">中括号形框</div>