body {
    overflow-y: auto;
}
    /*滚动条样式*/
    body::-webkit-scrollbar { /*滚动条整体样式*/
        width: 4px; /*高宽分别对应横竖滚动条的尺寸*/
        height: 4px;
    }

    body::-webkit-scrollbar-thumb { /*滚动条里面小方块*/
        border-radius: 5px;
        -webkit-box-shadow: inset 0 0 5px rgba(0,0,0,0.2);
        background: rgba(0,0,0,0.2);
    }

    body::-webkit-scrollbar-track { /*滚动条里面轨道*/
        -webkit-box-shadow: inset 0 0 5px rgba(0,0,0,0.2);
        border-radius: 0;
        background: rgba(0,0,0,0.1);
    }