Adds support for dark mode

AltStore/Components/NavigationBar.swift

@@ -32,19 +32,52 @@ class NavigationBar: UINavigationBar
     
     private func initialize()
     {
-        self.shadowImage = UIImage()
-        
-        if let tintColor = self.barTintColor
+        if #available(iOS 13, *)
         {
-            self.backgroundColorView.backgroundColor = tintColor
+            let standardAppearance = UINavigationBarAppearance()
+            standardAppearance.configureWithDefaultBackground()
+            standardAppearance.shadowColor = nil
             
-            // Top = -50 to cover status bar area above navigation bar on any device.
-            // Bottom = -1 to prevent a flickering gray line from appearing.
-            self.addSubview(self.backgroundColorView, pinningEdgesWith: UIEdgeInsets(top: -50, left: 0, bottom: -1, right: 0))
+            let edgeAppearance = UINavigationBarAppearance()
+            edgeAppearance.configureWithOpaqueBackground()
+            edgeAppearance.backgroundColor = self.barTintColor
+            edgeAppearance.shadowColor = nil
+            
+            if let tintColor = self.barTintColor
+            {
+                let textAttributes = [NSAttributedString.Key.foregroundColor: UIColor.white]
+                
+                standardAppearance.backgroundColor = tintColor
+                standardAppearance.titleTextAttributes = textAttributes
+                standardAppearance.largeTitleTextAttributes = textAttributes
+                
+                edgeAppearance.titleTextAttributes = textAttributes
+                edgeAppearance.largeTitleTextAttributes = textAttributes
+            }
+            else
+            {
+                standardAppearance.backgroundColor = nil
+            }
+            
+            self.scrollEdgeAppearance = edgeAppearance
+            self.standardAppearance = standardAppearance
         }
         else
         {
-            self.barTintColor = .white
+            self.shadowImage = UIImage()
+            
+            if let tintColor = self.barTintColor
+            {
+                self.backgroundColorView.backgroundColor = tintColor
+                
+                // Top = -50 to cover status bar area above navigation bar on any device.
+                // Bottom = -1 to prevent a flickering gray line from appearing.
+                self.addSubview(self.backgroundColorView, pinningEdgesWith: UIEdgeInsets(top: -50, left: 0, bottom: -1, right: 0))
+            }
+            else
+            {
+                self.barTintColor = .white
+            }
         }
     }