Gradient

gradient.css

main {
    background: linear-gradient(to bottom right, #4affde 0%, #5b9dff 40%, #d06bff 60%, #ff34d3 100%);
    background-size: 200% 200%;
    animation: movingGradient 5s linear infinite alternate;
}

@keyframes movingGradient {
    from { background-position: 0 0; }
    to   { background-position: 100% 100%; }
}