AppDelegate // Add a Bool to tell whether macOS is in Dark Mode.

Source/Modules/AppDelegate.swift

@@ -299,4 +299,19 @@ class AppDelegate: NSObject, NSApplicationDelegate, ctlNonModalAlertWindowDelega
             NSLog("vChewingErrorCallback: %@", strPrint)
         }
     }
+    @objc static func isDarkMode() -> Bool {
+        if #available(macOS 10.15, *) {
+            let appearanceDescription = NSApplication.shared.effectiveAppearance.debugDescription.lowercased()
+            if appearanceDescription.contains("dark") {
+                return true
+            }
+        } else if #available(macOS 10.14, *) {
+            if let appleInterfaceStyle = UserDefaults.standard.object(forKey: "AppleInterfaceStyle") as? String {
+                if appleInterfaceStyle.lowercased().contains("dark") {
+                    return true
+                }
+            }
+        }
+        return false
+    }
 }