< type="text/css"> .site{margin:100px auto 0;position:relative} .site-nav{width:100%;height:60px;background:#fff;margin-top:100px!important;border-radius:5px} .site-nav li{display:inline} .site-nav li a{display:inline-block;line-height:60px;font-size:14px;margin:0 10px 0 20px;transition:all .5s;position:relative} .site-nav li a:after{position:absolute;content:'';left:calc(50% - 10px);bottom:0;width:0;height:3px;background-color:#007bf5;transition:all .2s;-webkit-transition:all .2s;border-radius:20px} .site-nav .hover a{display:inline-block;color:#007bf5} .site-nav li a:hover{color:#1b8eff;transition:all .5s} .site-nav .hover a:after{width:20px}