fix: replace static bg colors with scss var

src/styles/scss/_gjs_inputs.scss

@@ -91,7 +91,7 @@
 }
 
 .#{$app-prefix}field {
-  background-color: rgba(0, 0, 0, 0.2);
+  background-color: $mainDkColor;
   border: none;
   box-shadow: none;
   border-radius: 2px;

src/styles/scss/_gjs_style_manager.scss

@@ -181,7 +181,7 @@
     }
 
     &.#{$sm-prefix}composite {
-      background-color: rgba(0, 0, 0, 0.1);
+      background-color: $mainDklColor;
       border: 1px solid rgba(0, 0, 0, 0.25);
     }