.lanmu li {position: relative;cursor: pointer;}
.lanmu .level1,
.lanmu .level2,
.lanmu .level3,
.lanmu .level4,
.lanmu .level5 {
    position: absolute;
    width: 100%;
    top: 0;
    left: 250px;
    z-index: 9999;
    background-color: #363e45;
    display: none;
}