diff --git a/ARCH.md b/ARCH.md
new file mode 100644
index 0000000..800300c
--- /dev/null
+++ b/ARCH.md
@@ -0,0 +1,12 @@
+# State Management
+
+We use a MultiProvider to distribute state to the underlying widgets. Right now there are 2 top
+level Providers: FlwtchState (the app) and OpaqueTheme.
+
+## Theme
+
+OpaqueTheme extends ChangeProvider. SetLight and SetDark are functions that call notifyListeners()
+
+ChangeNotiferProvider is used to package OpaqueTheme into a provider which is a top level
+provider (as every widget in the app needs to be re-rendered on a theme switch).
+
diff --git a/lib/main.dart b/lib/main.dart
index acc5fcc..2ce42d3 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -32,17 +32,17 @@ class FlwtchState extends State<Flwtch> {
   // mergenotes: ui stuff
   ProfileModel selectedProfile;
   String selectedConversation = "";
-  var columns = [1];// default or 'single column' mode
+  var columns = [1]; // default or 'single column' mode
   //var columns = [1, 1, 2];
 
   AppModel appStatus;
   HashMap<String, ProfileModel> profiles;
 
-
   @override
   initState() {
     super.initState();
     cwtchInit = false;
+
     profiles = new HashMap<String, ProfileModel>();
 
     print("FlwtchState.initState()");
@@ -80,32 +80,55 @@ class FlwtchState extends State<Flwtch> {
     });
   }
 
+  ChangeNotifierProvider<OpaqueTheme> getOpaqueProvider() {
+    return  ChangeNotifierProvider(create: (context) => OpaqueTheme(Opaque.dark));
+  }
+
+  Provider<FlwtchState> getFlwtchStateProvider() {
+    return Provider<FlwtchState>(
+      create: (_) => this,
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     appStatus = AppModel(cwtch: cwtch);
 
     final newTextTheme = Theme.of(context).textTheme.apply(
-      bodyColor: Opaque.current().mainTextColor(),
-      displayColor: Opaque.current().mainTextColor(),
-    );
+          bodyColor: Opaque.current().mainTextColor(),
+          displayColor: Opaque.current().mainTextColor(),
+        );
 
     print("FlwtchState.build() cwtchInit: $cwtchInit");
-    return Provider<FlwtchState>(
-        create: (_) => this,
-        child: MaterialApp(
-          title: 'Cwtch',
-          theme: ThemeData(
-            visualDensity: VisualDensity.adaptivePlatformDensity,
-            primarySwatch: Colors.red,
-            primaryColor: Opaque.current().backgroundMainColor(),
-            canvasColor: Opaque.current().backgroundPaneColor(),
-            accentColor: Opaque.current().defaultButtonColor(),
-            buttonColor: Opaque.current().defaultButtonColor(),
-            textTheme: newTextTheme,
-          ),
-          // from dan: home: cwtchInit == true ? ProfileMgrView(cwtch) : SplashView(),
-          // from erinn: home: columns.length == 3 ? TripleColumnView() : ProfileMgrView(),
-          home: cwtchInit == true ? (columns.length == 3 ? TripleColumnView() : ProfileMgrView()) : SplashView(),
-      ));
+    return MultiProvider(
+        providers: [getFlwtchStateProvider(), getOpaqueProvider()],
+        builder:  (context, widget) { return MaterialApp(
+              title: 'Cwtch',
+              theme: ThemeData(
+                visualDensity: VisualDensity.adaptivePlatformDensity,
+                primarySwatch: Colors.red,
+                primaryColor: Provider.of<OpaqueTheme>(context)
+                    .current()
+                    .backgroundMainColor(),
+                canvasColor: Provider.of<OpaqueTheme>(context)
+                    .current()
+                    .backgroundPaneColor(),
+                accentColor: Provider.of<OpaqueTheme>(context)
+                    .current()
+                    .defaultButtonColor(),
+                buttonColor: Provider.of<OpaqueTheme>(context)
+                    .current()
+                    .defaultButtonColor(),
+                textTheme: newTextTheme,
+              ),
+              // from dan: home: cwtchInit == true ? ProfileMgrView(cwtch) : SplashView(),
+              // from erinn: home: columns.length == 3 ? TripleColumnView() : ProfileMgrView(),
+              home: cwtchInit == true
+                  ? (columns.length == 3
+                      ? TripleColumnView()
+                      : ProfileMgrView())
+                  : SplashView(),
+        );},
+    );
   }
-}
\ No newline at end of file
+}
diff --git a/lib/opaque.dart b/lib/opaque.dart
index fa81b31..0282dcd 100644
--- a/lib/opaque.dart
+++ b/lib/opaque.dart
@@ -5,6 +5,8 @@
 
 import 'dart:ui';
 import 'dart:core';
+
+import 'package:flutter/material.dart';
 abstract class OpaqueThemeType {
     static final Color red = Color(0xFFFF0000);
     Color backgroundMainColor(){return red;}
@@ -421,9 +423,12 @@ class Opaque extends OpaqueThemeType {
     int chatPaneMinSize() { return chatPaneMinSizeBase[p[scale]]; }
     int doublePaneMinSize() { return sidePaneMinSize() + chatPaneMinSize(); }
 
+    static OpaqueThemeType _current;
     static final OpaqueThemeType dark = CwtchDark();
     static final OpaqueThemeType light = CwtchLight();
-    static OpaqueThemeType current() { return dark; }
+    static void setDark() { _current = dark; }
+    static void setLight() { _current = light; }
+    static OpaqueThemeType current() { if (_current == null) {setDark();} return _current; }
 
     
 int scale = 2;
@@ -507,3 +512,15 @@ int scale = 2;
     
     
 }
+
+
+
+/// TODO: Wire into libCwtch saveSettings / updateTheme etc...
+class OpaqueTheme extends ChangeNotifier {
+    OpaqueThemeType theme;
+    void setDark() { theme = Opaque.dark;     notifyListeners();}
+    void setLight() { theme = Opaque.light;     notifyListeners();}
+    OpaqueThemeType current() { return theme; }
+
+    OpaqueTheme(this.theme);
+}
\ No newline at end of file
diff --git a/lib/views/globalsettingsview.dart b/lib/views/globalsettingsview.dart
index d61a981..bdbe5df 100644
--- a/lib/views/globalsettingsview.dart
+++ b/lib/views/globalsettingsview.dart
@@ -1,4 +1,7 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_app/main.dart';
+import 'package:flutter_app/opaque.dart';
+import 'package:provider/provider.dart';
 
 class GlobalSettingsView extends StatefulWidget {
   @override
@@ -35,7 +38,18 @@ class _GlobalSettingsViewState extends State<GlobalSettingsView> {
           },
         ),
         Text("Zoom"),
-        Text("Theme"),
+        SwitchListTile(
+          title: const Text('Theme'),
+          value: Provider.of<OpaqueTheme>(context).current() == Opaque.light,
+          onChanged: (bool value) {
+              if (value) {
+                Provider.of<OpaqueTheme>(context, listen: false).setLight();
+              } else {
+                Provider.of<OpaqueTheme>(context, listen: false).setDark();
+              }
+          },
+          secondary: const Icon(Icons.lightbulb_outline),
+        ),
         Text("Experiments enabled"),
         Text("Text magnification reference"),
         Text("Acknowledgements"),