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/styles/base.css

@@ -1,3 +1,5 @@
+@custom-variant dark (&:where(.dark, .dark *));
+
 @theme {
 	/* Fonts - easily overrideable */
 	--font-*: initial;