header{
    height: 100vh;
    width: 100%;
}

#loading{
    position: fixed;
    width: 100%;
    height: 100vh;
    background: #fff url('https://media0.giphy.com/media/kUTME7ABmhYg5J3psM/giphy.gif?cid=ecf05e47sw87t5tqdmap7a69oz2euz8cg1rwn4reppo4h467&rid=giphy.gif&ct=g')
    no-repeat center;
    z-index: 1000;
}