opera,谷歌兼容样式

@media all and (-webkit-min-device-pixel-ratio:10000), not all and (-webkit-min-device-pixel-ratio:0){head~body .tabs { top:6px;}}/*opera*/
@media screen and (-webkit-min-device-pixel-ratio:0){body:nth-of-type(1) .tabs{ top:4px;}} /*chrome与Safari*/