chore(docs): elaborate on themes a little

README.md

@@ -242,7 +242,7 @@ better dictation of the information on screen for the visually impaired.
 
 ## Themes
 
-Forms can be themed.
+`huh?` contains a powerful theme abstraction.
 
 Supply your own custom theme or choose from one of the four predefined themes:
 
@@ -259,6 +259,12 @@ Supply your own custom theme or choose from one of the four predefined themes:
     <img alt="Default-themed form" width="400" src="https://stuff.charm.sh/huh/themes/default-theme.png">
 </p>
 
+Themes are more then just colors: they can take advantage of the full range of
+[Lip Gloss][lipgloss] style. For high level theme reference see 
+[the docs](https://pkg.go.dev/github.com/charmbracelet/huh#Theme).
+
+[lipgloss]: https://github.com/charmbracelet/lipgloss
+
 ## Spinner
 
 Spinners come built in to `huh` for loading actions. It's useful to indicate