#clock{
    float: right;
    display: block;
    color: white;
    padding: 14px 16px;
}

.nav a:hover {
    text-decoration: none;
    background-color: #ddd;
}

li {
    list-style-type: none;
}

.nav{
    user-select: none;
    height: 50px;
    background-color: #333;
    border-radius: 12px;
}

.nav ul {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}

.nav ul li {
    float: left;
    width: 80px;  
    height: 100%;
    text-align: center;
    line-height: 50px;
    margin-left: 10px;
    margin: 0;
    padding: 0;
}

.nav ul li a{
    color: white;
    text-decoration: none;
    display: block;
}

.nav ul li a:hover {
    color: black;
}

.nav ul li div {
    overflow: hidden;
    position: absolute;
    width: auto;
    height: 0;
    background-color: #333;
    transition: height 0.2s ,border 0.2s linear;
    -moz-transition:height 0.2s ,border 0.2s linear;
    -webkit-transition:height 0.2s ,border 0.2s linear;
    -o-transition:height 0.2s ,border 0.2s linear;
}

.nav ul li:hover div {
    height: 50px;
    z-index: 10;
}

.nav ul li div ul li {
    margin: 10px 2px 10px 2px;
    width: auto;
    height: auto;
    line-height: 30px;
}

.nav ul li div ul li a{
    display: block;  
    color: white;
}