.yk-lecture-room-container .sidebar-menu{z-index:2000}.yk-lecture-room-container .BlackBoard{position:fixed;top:0;left:0;width:100%;height:100%;z-index:2503}.yk-lecture-room-container .BlackBoard .black-bottom-footer{width:100%;height:51px;background:#304b4b;position:fixed;bottom:0;left:0;z-index:2001}.yk-lecture-room-container .menul-ul-left li{padding:5px 0}.yk-lecture-room-container .linkActive{background-color:#3fa2ff}.yk-lecture-room-container .teach-PhotoWall-wrapper{position:fixed;top:0;width:calc(100% - 146px);height:100%;z-index:2001;background:#304b4b;overflow-y:auto;left:79px}