/*
class 声明用'.'引用
.xpy {
}

id 声明用'#'引用
#demo {
}

标签 直接引用
p {
}
*/

body {
    box-sizing: border-box;
    display: flex;
    display: -webkit-flex;
    flex-direction: column;
    -webkit-flex-direction: column;
    background-color:white;
    width:100%;
    height:100%;
    margin:0;
    padding-top:40px;
}

div.l_header {
   margin-left: 30px;
}

ul.l_nav {
    box-sizing: border-box;
    position: fixed;
    top: 0;
    list-style-type: none;
    margin: 0;
    padding: 0;
    width: 100%;
    height: auto;
    overflow: hidden;
    background-color: #333;
}

ul.l_nav li {
    float: left;
}

ul.l_nav li a {
    display: block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

ul.l_nav li a:hover:not(ul.l_nav li a.active):not(ul.l_nav li.l_user_avatar a) {
    background-color: #111;
}

ul.l_nav li a.active {
    background-color: #4CAF50;
}

ul.l_nav li.l_user_avatar {
    float: right;
    box-sizing: border-box;
    display: flex;
    display: -webkit-flex;
    flex-direction: row;
    -webkit-flex-direction: row;
    align-items: center;
}

ul.l_nav li.l_user_avatar a {
    padding: 0;
}

ul.l_nav li.l_user_avatar h5 {
    color: white;
    margin: 0px;
}

ul.l_nav li.l_user_avatar img {
    padding: 0;
    margin: 8px;
    width: 30px;
    height: 30px;
    border-radius: 15px;
    object-fit:cover;
}

div.l_cnt {
    box-sizing: border-box;
    display: flex;
    display: -webkit-flex;
    flex-direction: row;
    -webkit-flex-direction: row;
    width: 100%;
    height: 100%;
    margin-bottom: 40px;
}

div.l_cnt_l {
    box-sizing: border-box;
    display: flex;
    display: -webkit-flex;
    flex-direction: column;
    -webkit-flex-direction: column;
    width: 100%;
    height: 100%;
}

div.l_cnt_r {
    box-sizing: border-box;
    display: flex;
    display: -webkit-flex;
    flex-direction: column;
    -webkit-flex-direction: column;
    min-width: 260px;
    max-height: 300px;
    height: auto;
}

footer.l_footer {
    box-sizing: border-box;
    position: fixed;
    padding: 6px;
    width: 100%;
    bottom: 0;
    height: 40px;
    background-color: whitesmoke;
}

footer.l_footer a.beian {
    text-decoration: none;
    color: gold;
}

footer.l_footer a.beian:hover {
    color: red;
}