@@ -7,8 +7,57 @@
 //
 
 #import "NSAppearance+PBDarkMode.h"
+#import <objc/runtime.h>
 
 // This definition satisfies the `extern NSString *const` declaration in the
 // header for all Objective-C callers.  The Swift side imports the same value
 // as a plain Swift String via the bridging header.
 NSString *const PBEffectiveAppearanceChanged = @"PBEffectiveAppearanceChanged";
+
+@implementation NSAppearance (PBDarkMode)
+
+- (BOOL)isDarkMode
+{
+	NSAppearanceName bestMatch = [self bestMatchFromAppearancesWithNames:@[NSAppearanceNameDarkAqua, NSAppearanceNameAqua]];
+	return [bestMatch isEqualToString:NSAppearanceNameDarkAqua];
+}
+
+@end
+
+@implementation NSApplication (PBDarkMode)
+
+- (BOOL)isDarkMode
+{
+	return self.effectiveAppearance.isDarkMode;
+}
+
+static char kAppearanceObservationKey;
+
+- (void)registerObserverForAppearanceChanges:(id)observer
+{
+	// Use traditional KVO addObserver method
+	[self addObserver:self
+		   forKeyPath:@"effectiveAppearance"
+			  options:NSKeyValueObservingOptionNew
+			  context:&kAppearanceObservationKey];
+
+	// Store the observer reference
+	objc_setAssociatedObject(self, &kAppearanceObservationKey, observer, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+}
+
+- (void)observeValueForKeyPath:(NSString *)keyPath
+					  ofObject:(id)object
+						change:(NSDictionary *)change
+					   context:(void *)context
+{
+	if (context == &kAppearanceObservationKey) {
+		id observer = objc_getAssociatedObject(self, &kAppearanceObservationKey);
+		[[NSNotificationCenter defaultCenter] postNotificationName:PBEffectiveAppearanceChanged
+															object:observer];
+	} else {
+		[super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
+	}
+}
+
+@end
+