/* header */
header {
    width: 100%;
    height: 80px;
    background-color: #50616d;
    position: relative;
    z-index: 10000;
}

header div,
footer div {
    margin: auto;
    width: 1200px;
}

header img {
    float: left;
    display: block;
    padding-top: 10px;
    height: 60px;
    cursor: pointer;
}

header nav {
    float: left;
    margin-top: 50px;
}

.nav-lv1>li {
    float: left;
    margin-left: 60px;
    font-size: 20px;
    color: #eeeeee;
}

.nav-lv1>li:hover,
.nav-lv2>li:hover {
    color: #e55709;
}

.nav-lv2 {
    display: none;
    position: absolute;
    font-size: 16px;
    color: #eeeeee;
    background-color: #50616d;
}

.nav-lv2>li {
    height: 30px;
    padding: 5px;
}

.nav-lv1 li:hover .nav-lv2 {
    display: block;
}

/* main */
main {
    margin: auto;
    margin-top: 20px;
    width: 1200px;
    color: black;
}

main::before,
main::after {
    content: '';
    display: table;
}

main::after {
    clear: both;
}

/* footer */
footer {
    margin: auto;
    padding-top: 5px;
    width: 100%;
    height: 45px;
    background-color: #50616d;
    line-height: 20px;
    color: #cccccc;
    text-align: center;
}

footer a:hover {
    color: #e55709;
}

footer img {
    height: 40px;
}

html {
    height: 100%;
}

/* let footer sticky at bottom */
body {
    min-height: 100%;
    display: flex;
    flex-direction: column;
}

main {
    flex: 1;
}