*[parallax]::after,
*[parallax]::before {
    animation: parallax linear;
    animation-timeline: scroll();
}

main[parallax] {
    --parallax-speed: 0.5;
}

section[parallax]:nth-child(1) {
    --parallax-speed: 1;
}

section[parallax]:nth-child(2) {
    --parallax-speed: 2;
}

section[parallax]:nth-child(3) {
    --parallax-speed: 3;
}

@keyframes parallax {
    to {
        top: calc(var(--parallax-speed) * var(--size-parallax));
    }
}