html, body {
    height: 100%;
    text-align: center;
}

.parent {
    position: relative;
    background: none;
    height: 100%;
    width: 100%;
}

.parent h1{
    position: absolute;
    top:50%;
    left:50%;
    -webkit-transform: translate(-50%,-50%);
    transform: translate(-50%,-50%);
    width: 100%;
    text-align: center;
    color:white;
}

body:after {
    position: fixed;
    top:0; left:0;
    width: 100%;
    height: 100%;
    content: "";
    background: rgb(2,0,36);
    background: -moz-linear-gradient(25deg, rgba(2,0,36,1) 0%, rgba(9,9,121,1) 0%, rgba(0,212,255,1) 100%);
    background: -webkit-linear-gradient(25deg, rgba(2,0,36,1) 0%, rgba(9,9,121,1) 0%, rgba(0,212,255,1) 100%);
    background: linear-gradient(25deg, rgba(2,0,36,1) 0%, rgba(9,9,121,1) 0%, rgba(0,212,255,1) 100%);
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr="#020024",endColorstr="#00d4ff",GradientType=1); 
    z-index: -1;
    background-size: 300% 300%;
    animation: color 6s ease-in-out infinite;
}
@keyframes color{
    0%{
        background-position: 0 50%;
    }
    50%{
        background-position: 100% 50%;
    }
    100%{
        background-position: 0 50%;
    }
}