body {
    --angle: 0deg;
    background: linear-gradient(rgb(from var(--background-dark-color) r g b / var(--alpha)) 0 0) padding-box, conic-gradient(from var(--angle), red, yellow, lime, aqua, blue, magenta, red) border-box;
    animation: 0.2s appear ease-out forwards, 30s rotate linear infinite;
}

@keyframes rotate {
    to {
	--angle: 360deg;
    }
}

@property --angle {
    syntax: '<angle>';
    initial-value: 0deg;
    inherits: false;
}