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/dees-spinner/dees-spinner.ts

@@ -11,6 +11,7 @@ import {
 } from '@design.estate/dees-element';
 
 import * as domtools from '@design.estate/dees-domtools';
+import { themeDefaultStyles } from '../00theme.js';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -46,8 +47,10 @@ export class DeesSpinner extends DeesElement {
   }
 
   public static styles = [
+    themeDefaultStyles,
     cssManager.defaultStyles,
     css`
+      /* TODO: Migrate hardcoded values to --dees-* CSS variables */
       :host {
         display: block;
       }