.nav a{display: inline-block; width:100px;  line-height:40px; border:1px solid #ececec;  text-align: center;  font-size: 14px;}
.nav .hehe:hover{background:url(http://img0.imgtn.bdimg.com/it/u=2254720917,2844935593&fm=21&gp=0.jpg);color:#fff}