body{width:100%;height:900px;} #app_header>img{width:100%;} .sm_title{text-align: center;height:50px;line-height: 50px;font-size: 16px;letter-spacing: 2px; margin-bottom: 10px;} .center_img{text-align: center;margin-bottom: 10px;} .center_img>img{width:100%;} .active_title{border-bottom: 2px solid #0066CC;}