feat(theme,interfaces): Introduce a global theming system and unify menu/tab interfaces; migrate components to use themeDefaultStyles and update APIs accordingly

ts_web/elements/00group-input/dees-input-dropdown/dees-input-dropdown.ts

@@ -11,6 +11,7 @@ import * as domtools from '@design.estate/dees-domtools';
 import { demoFunc } from './dees-input-dropdown.demo.js';
 import { DeesInputBase } from '../dees-input-base/dees-input-base.js';
 import { cssGeistFontFamily } from '../../00fonts.js';
+import { themeDefaultStyles } from '../../00theme.js';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -60,9 +61,11 @@ export class DeesInputDropdown extends DeesInputBase<DeesInputDropdown> {
   accessor searchValue: string = '';
 
   public static styles = [
+    themeDefaultStyles,
     ...DeesInputBase.baseStyles,
     cssManager.defaultStyles,
     css`
+      /* TODO: Migrate hardcoded values to --dees-* CSS variables */
       * {
         box-sizing: border-box;
       }