Add some detail around how colors are defined

web/stories/Colors.stories.mdx

@@ -5,6 +5,12 @@ import { Color, ColorRow } from './Color';
 
 # Colors
 
+These colors are assigned in our [color token](https://github.com/owncast/owncast/tree/webv2/web/style-definitions/tokens/color) files
+and get reflected here as they change.
+
+Toggle dark mode on and off in the above toolbar to see how these colors look on a dark vs. light background.
+
+## Key Colors
 
 <ColorRow colors={['theme-primary-color', 'theme-text-color-secondary']} />