Customise window decorations, add openfolder action to menu, fix toolbar colours

src/styles.scss

@@ -1,10 +1,17 @@
-@use '@angular/material' as mat;
-@use './m3-theme.scss';
+@use "@angular/material" as mat;
+@use "./theme.scss";
 
 @include mat.core();
 
+@mixin custom-colours($theme) {
+  .mat-toolbar {
+    background-color: mat.get-theme-color($theme, primary-container);
+  }
+}
+
 html {
-    @include mat.all-component-themes(m3-theme.$dark-theme);
+  @include mat.all-component-themes(theme.$rose-theme);
+  @include custom-colours(theme.$rose-theme);
 }
 
 html,