fix(page): Use theme variables for page styling, make pagecontainer background theme-aware, and use accent background for footer separator

ts_web/elements/pagecontainer.ts

@@ -50,7 +50,7 @@ export class DePageContainer extends DeesElement {
         position: relative;
         border-radius: 3px;
         overflow: hidden;
-        background: #ffffff;
+        background: var(--text-bg-color, #ffffff);
       }
     `,
   ];