fix: skip all dark theme styles when dark theme selector is set to false (#139)

Author: json-derulo

projects/material-css-vars/src/lib/_public-util.scss

@@ -139,8 +139,10 @@
 }
 
 @mixin mat-css-dark-theme-global {
-  #{variables.$dark-theme-selector} & {
-    @content;
+  @if variables.$dark-theme-selector {
+    #{variables.$dark-theme-selector} & {
+      @content;
+    }
   }
 }
 
@@ -155,8 +157,10 @@
   #{variables.$light-theme-selector} & {
     @content;
   }
-  #{variables.$dark-theme-selector} & {
-    @content;
+  @if variables.$dark-theme-selector {
+    #{variables.$dark-theme-selector} & {
+      @content;
+    }
   }
 }