Fix preferences post preview background on macOS

Tusker/Screens/Preferences/Appearance/AppearancePrefsView.swift

@@ -49,7 +49,7 @@ struct AppearancePrefsView: View {
                     .padding(.top, 8)
                     .padding(.horizontal, UIDevice.current.userInterfaceIdiom == .pad ? 8 : 4)
             }
-            .listRowBackground(preferences.pureBlackDarkMode ? colorScheme == .dark ? Color.black : Color.white : Color.appBackground)
+            .listRowBackground(mockStatusBackground)
             
             accountsSection
             postsSection
@@ -60,6 +60,22 @@ struct AppearancePrefsView: View {
         .navigationTitle("Appearance")
     }
     
+    private var mockStatusBackground: Color? {
+        #if targetEnvironment(macCatalyst)
+        nil
+        #else
+        if ProcessInfo.processInfo.isiOSAppOnMac {
+            nil
+        } else if !preferences.pureBlackDarkMode {
+            .appBackground
+        } else if colorScheme == .dark {
+            .black
+        } else {
+            .white
+        }
+        #endif
+    }
+    
     private var themeSection: some View {
         Section {
             #if !os(visionOS)