undo forwarding mdc-core-color to core-color

Author: mmalerba

src/material-experimental/mdc-core/_core-theme.scss

@@ -1,7 +1,36 @@
+@use 'sass:map';
 @use '@angular/material' as mat;
 
 @mixin color($config-or-theme) {
-  @include mat.core-color($config-or-theme);
+  $config: mat.get-color-config($config-or-theme);
+
+  @include mat.option-color($config);
+  @include mat.optgroup-color($config);
+
+  @if $config != null {
+    // Provides external CSS classes for each elevation value. Each CSS class is formatted as
+    // `mat-mdc-elevation-z$zValue` where `$zValue` corresponds to the z-space to which the
+    // element is elevated.
+    @for $zValue from 0 through 24 {
+      $selector: 'mat-mdc-elevation-z' + $zValue;
+      // We need the `mat-mdc-elevation-specific`, because some MDC mixins
+      // come with elevation baked in and we don't have a way of removing it.
+      .#{$selector}, .mat-mdc-elevation-specific.#{$selector} {
+        @include mat.private-theme-elevation($zValue, $config);
+      }
+    }
+
+    // Wrapper element that provides the theme background when the user's content isn't
+    // inside of a `mat-sidenav-container`. Note that we need to exclude the ampersand
+    // selector in case the mixin is included at the top level.
+    .mat-mdc-app-background#{if(&, ', &.mat-mdc-app-background', '')} {
+      $background: map.get($config, background);
+      $foreground: map.get($config, foreground);
+
+      background-color: mat.get-color-from-palette($background, background);
+      color: mat.get-color-from-palette($foreground, text);
+    }
+  }
 }
 
 @mixin typography($config-or-theme) {