#main-banner{ overflow: auto; .banner{ width: 375px; height: 183px; background: url("https://julyedu-cdn.oss-cn-beijing.aliyuncs.com/active19_1111/m/banner.png") no-repeat; background-size: contain; } .formal_banner { background: url("https://julyedu-cdn.oss-cn-beijing.aliyuncs.com/active19_1111/m/formal_banner.png") no-repeat; background-size: contain; } .fc_banner { background: url('https://julyedu-cdn.oss-cn-beijing.aliyuncs.com/active19_1111/m/fc_banner.png') center center no-repeat; background-size: 100% 100%; } #main-nav{ position: absolute; top: 183px; width: 100%; margin-bottom:30px; &.fixed{ position: fixed; top: 0; z-index: 100; } ul{ background: #3900C9; display: flex; } li{ flex: 1; width: 63px; height: 40px; font-size: 11px; color: #fff; text-align: center; line-height: 40px; &.active{ background: #FF42F9; } } } }