test-card/src/lib/ColorGradient.svelte

<div class="gradient"></div>

<style>
	.gradient {
		width: 100%;
		height: 100%;

		background: linear-gradient(
			180deg,
			#ff0000,
			#ff7f00,
			#ffff00,
			#00ff00,
			#0000ff,
			#4b0082,
			#9400d3
		);
	}
</style>