clean up stitches theme config

lib/config/themes.ts

@@ -1,19 +0,0 @@
-import { theme, darkTheme } from "../styles/stitches.config";
-
-// theme classnames are generated dynamically by stitches, so have ThemeProvider pull them from there
-export const themeClassNames = {
-  light: theme.className,
-  dark: darkTheme.className,
-};
-
-// colors used for `<meta name="theme-color" .../>` (see components/Layout/Layout.tsx)
-export const themeColors = {
-  light: theme.colors.backgroundOuter?.value,
-  dark: darkTheme.colors.backgroundOuter?.value,
-};
-
-// default/fallback theme
-export const themeDefault = "light";
-
-// local storage key
-export const themeStorageKey = "theme";