*{
    margin:0;
    padding:0;
}
html,body{
    width:100%;
    height:100%;
    background-color: #000;
    overflow: hidden;
}
#clock {
    position: relative;
    width: 100%;
    height: 100%;
    background: black;
}
.label{
    position: absolute;
    top: 50%;
    left: 50%;
    display:inline-block;
    color:#4d4d4d;
    text-align: center;
    padding:0 5px;
    font-size:19px;
    transition:all 1s;
    transform: translate(-50%,-50%);
    transform-origin: 0% 0%;
}
.now{
    color: #fff;
}

#screen-change{position:absolute;left:50%;top:50%;overflow:hidden;z-index:10}
#screen-change.w{height:100vw;width:100vh;transform:translate(-50%,-50%) rotate(90deg);-webkit-transform:translate(-50%,-50%) rotate(90deg)}
#screen-change.h{height:100vh;width:100vw;transform:translate(-50%,-50%);-webkit-transform:translate(-50%,-50%)}