HTMLify

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: "Titillium Web", sans-serif;
    position: relative;
    width: 100vw;
    min-height: 100vh;
    background: #000;
    color: #fff;
    background-size: 300%;
    animation: bg-animation 20s linear infinite;
}

h1 {
    font-size: 600%;
    font-weight: 900;
    letter-spacing: 0;

    color: transparent;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    -webkit-background-clip: text;
    background-image: linear-gradient(245deg,
            rgba(153, 169, 255, 1) 20%,
            rgba(252, 255, 0, 1) 48%,
            rgba(178, 101, 255, 1) 75%);
    background-size: 140%;
    animation: bg-animation 3s linear infinite;
}

header {
    position: relative;
    width: 100%;
    height: 80vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgb(0, 5, 34);
    background: linear-gradient(245deg,
            rgba(0, 5, 34, 1) 38%,
            rgba(58, 1, 115, 1) 65%);
    border-radius: 0 0 60% 60% / 0 0 100% 100%;
    transform: scaleX(1.5);
    z-index: -1;
}

@keyframes bg-animation {
    0% {
        background-position: 0% 0%;
    }

    50% {
        background-position: 100% 100%;
    }

    100% {
        background-position: 0% 0%;
    }
}