clean up consumer styling

Consumer now only imports the styles endpoint from their main CSS file.
Dark mode is currently permanently disabled, I need to add a JS helper
that when used automatically adds the correct class if there is a
preferred color scheme.

Also gets rid of the whole weird thing where the consumer had to have
a SPECIFIC `theme.css` file.

src/lib/DateInput.svelte

@@ -311,7 +311,7 @@
 {/snippet}
 
 <style lang="postcss">
-	@reference "$lib/styles/tailwind.css";
+	@reference "./styles/reference.css";
 
 	.date-input {
 		@apply ring-sui-accent dark:ring-sui-accent/50 h-6 min-w-[1ch] outline-0 transition-all focus:ring-2;