/* - 侧边栏 */
.sidebar{
    top: 0;
    left: 0;
    bottom: 0;
    color: #fff;
    width: 250px;
    position: fixed;
    overflow: hidden;
    overflow-y: auto;
    background:rgba(255,255,255,0.6);
}

/* -- 头像 */
.sidebar .avatar{
    width: 160px;
    height: 160px;
    margin: 2em auto;
    background: #fff;
    border-radius: 100%;
    border: #fff 5px solid;
    transition: transform 0.5s;
}
.sidebar .avatar:hover{
    transform: rotate(1turn);
}
.sidebar .avatar img{
    border-radius: 100%;
}

/* -- 侧边栏导航 */
.sidebar .nav{
    margin: 0;
    display: flex;
    list-style: none;
    flex-direction: column;
}
.sidebar .nav a{
    color: #fff;
    padding: 1em;
    display: block;
    text-align: center;
    transition: background .3s, box-shadow .3s;
}
.sidebar .nav a:hover{
    background: rgba(0, 0, 0, .2);
}




@media screen and (max-width: 900px) {
    .sidebar {
        width: inherit;
        position: relative;
    }
    .sidebar .nav{
        background: #f8bd24;
        flex-direction: row;
        justify-content: center;
    }
    .sidebar .nav a:hover{
        background: none;
        box-shadow: 0 -3px 0 #fff inset;
    }
    main{
        margin-left: 0;
    }
}

@media print{
    .sidebar{
        display: none;
    }
    main{
        margin-left: 0;
    }
}