*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
section{
    width: 100%;
    height: 100vh;
    
    background: linear-gradient(90deg, #3f51b5,#00bcd4);
    animation: animate 20s linear infinite;
}
@keyframes animate{
    0%{
        filter: hue-rotate(0deg);
    }
    50%{
        filter: hue-rotate(360deg);
    }
    100%{
        filter: hue-rotate(0deg);
    }
}