.left {
            position: fixed;
            width: 250px;
            height: 100%;
            top: 0;
            left: 0;
            overflow-x: hidden;
            overflow-y: auto;
            -ms-overflow-style: none;
            padding-top: 20px;
        }

        .left::-webkit-scrollbar {
            display: none;
        }

        .left a {
            display: inline-block;
            width: 230px;
            height: 30px;
            line-height: 30px;
            color: rgb(150,150,150);
            text-decoration: none;
            padding-left: 20px;
        }

        .left a:hover {
            color: black;
            background-color: rgb(230, 230, 230);
        }

        .right {
            position: absolute;
            left: 300px;
            box-shadow: 0 0 25px black;
            padding: 20px 20px;
            background-color: rgb(250,250,250);
        }
        *{
            font-family: "等线";
        }