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-stepper/dees-stepper.ts

@@ -15,6 +15,7 @@ import {
 
 import * as domtools from '@design.estate/dees-domtools';
 import { stepperDemo } from './dees-stepper.demo.js';
+import { themeDefaultStyles } from '../00theme.js';
 
 export interface IStep {
   title: string;
@@ -50,8 +51,10 @@ export class DeesStepper extends DeesElement {
   }
 
   public static styles = [
+    themeDefaultStyles,
     cssManager.defaultStyles,
     css`
+      /* TODO: Migrate hardcoded values to --dees-* CSS variables */
       :host {
         position: absolute;
         width: 100%;