#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; } } } }