JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrap"><div class="inner"></div></div>

<br></br>
What I see in chrome 34 on Mac OS X 10.9.2:
<img src="http://f.cl.ly/items/1m2o431f2k1J2E1t3X0H/Image%202014-04-18%20at%202.24.23%20%D0%BF%D0%BE%D1%81%D0%BB%D0%B5%20%D0%BF%D0%BE%D0%BB%D1%83%D0%B4%D0%BD%D1%8F.png">

CSS

.wrap {
    position: relative;
    width: 200px; 
    height: 66px;
    background: black;
    overflow: hidden;
    border-radius: 100px;
}

.inner {
    position: absolute;
    top: 0;
    left: 50%;
    right: 0;
    bottom: 0;
    background: white;
}