<style>
       .pxc 
	   {
         <!-- border-top: 1px solid #e0e0e0; -->
         background-position: left top;
         background-image:linear-gradient(to top, transparent 0%,transparent 50%,#e0e0e0 50%,#e0e0e0 100%);
	 background-image: -ms-linear-gradient(bottom, transparent 0%,transparent 50%,  #e0e0e0 50%, #e0e0e0 50%);
	 background-image: -webkit-gradient(linear, left bottom, left top, color-stop(0.5, transparent), color-stop(0.5, #e0e0e0), to(#e0e0e0)); 
	 background-repeat: repeat-x;
         -webkit-background-size: 100% 1px;
	  background-size: 100% 1px;
	    }
       </style> 

用腾讯的Frozen UI最大的感悟就是它的半像素，原理就是通过渐变把1像素的下面部分弄成透明，因此只要把各个浏览器的渐变css写上去就可以实现兼容

Frozen UI中提取的半像素边框