Add dark mode switch

ResumeBuilder/ContentView.swift

@@ -3,9 +3,27 @@ import SFSafeSymbols
 
 struct ContentView: View {
 
+    @Environment(\.colorScheme)
+    var defaultColorScheme: ColorScheme
+
     let info: CVInfo
 
     let style: CVStyle
+
+    init(info: CVInfo, style: CVStyle) {
+        self.info = info
+        self.style = style
+    }
+
+    @State
+    var darkModeEnabled = true
+
+    @State
+    var didReadDarkMode = false
+
+    var colorStyle: ColorScheme {
+        darkModeEnabled ? .dark : .light
+    }
     
     var body: some View {
         VStack(alignment: .leading) {
@@ -14,11 +32,20 @@ struct ContentView: View {
                     Label("Save", systemSymbol: .squareAndArrowUp)
                 }
                 .padding()
+                Toggle("Dark mode", isOn: $darkModeEnabled)
             }
             ScrollView(.vertical) {
                 CV(info: info, style: style)
             }.frame(width: style.pageWidth)
         }
+        .preferredColorScheme(colorStyle)
+        .onAppear {
+            guard !didReadDarkMode else {
+                return
+            }
+            darkModeEnabled = defaultColorScheme == .dark
+            didReadDarkMode = true
+        }
     }
 
     private func createAndSavePDF() {