Demo
CSS
.value {
height:100%;
width:100%;
border-radius:100%;
box-shadow: 0 0 0 2px #FFFFFF, 0 0 5px rgba(0, 0, 0, 0.1) inset;
position:absolute;
background: -moz-linear-gradient(top, #3498db 0%, #3498db 50%, #FFFFFF 50%, #FFFFFF 100%);
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #3498db), color-stop(50%, #3498db), color-stop(50%, #FFFFFF), color-stop(100%, #FFFFFF));/* Chrome,Safari4+ */
background: -webkit-linear-gradient(top, #3498db 0%, #3498db 50%, #FFFFFF 50%, #FFFFFF 100%);/* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top, #3498db 0%, #3498db 50%, #FFFFFF 50%, #FFFFFF 100%);/* Opera11.10+ */
background: -ms-linear-gradient(top, #3498db 0%, #3498db 50%, #FFFFFF 50%, #FFFFFF 100%);/* IE10+ */
background: linear-gradient(top, #3498db 0%, #3498db 50%, #FFFFFF 50%, #FFFFFF 100%);/* W3C */
}
使它起作用的技巧也是 limitation.... 使用来自 @987654325 的 linear-gradient @ 颜色...要以完美的外观动态设置它会很困难...
希望对您有所帮助..!!