Tweak appearance.

Signal/src/ViewControllers/AppSettings/AdvancedSettingsTableViewController.m

@@ -195,11 +195,11 @@ NS_ASSUME_NONNULL_BEGIN
     }
     [contents addSection:censorshipSection];
 
-#ifdef DEBUG
+#ifdef THEME_ENABLED
     OWSTableSection *themeSection = [OWSTableSection new];
     themeSection.headerTitle = NSLocalizedString(@"THEME_SECTION", nil);
     [themeSection addItem:[OWSTableItem switchItemWithText:NSLocalizedString(@"SETTINGS_ADVANCED_THEME", @"")
-                                                      isOn:[Environment.preferences isThemeEnabled]
+                                                      isOn:[UIColor isThemeEnabled]
                                                     target:weakSelf
                                                   selector:@selector(didToggleThemeSwitch:)]];
     [contents addSection:themeSection];
@@ -286,7 +286,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)didToggleThemeSwitch:(UISwitch *)sender
 {
-    [Environment.preferences setIsThemeEnabled:sender.isOn];
+    [UIColor setIsThemeEnabled:sender.isOn];
 
     // TODO: Notify and refresh.
 }

SignalMessaging/categories/UIColor+OWS.h

@@ -6,6 +6,10 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+#ifdef DEBUG
+#define THEME_ENABLED
+#endif
+
 @interface UIColor (OWS)
 
 #pragma mark - Global App Colors
@@ -77,6 +81,13 @@ NS_ASSUME_NONNULL_BEGIN
 @property (class, readonly, nonatomic) UIColor *ows_grey600Color;
 @property (class, readonly, nonatomic) UIColor *ows_darkSkyBlueColor;
 
+#pragma mark - Theme
+
+#ifdef THEME_ENABLED
++ (BOOL)isThemeEnabled;
++ (void)setIsThemeEnabled:(BOOL)value;
+#endif
+
 @end
 
 NS_ASSUME_NONNULL_END

SignalMessaging/categories/UIColor+OWS.m

@@ -2,12 +2,17 @@
 //  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
-#import "UIColor+OWS.h"
 #import "OWSMath.h"
+#import "UIColor+OWS.h"
 #import <SignalServiceKit/Cryptography.h>
+#import <SignalServiceKit/OWSPrimaryStorage.h>
+#import <SignalServiceKit/YapDatabaseConnection+OWS.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
+NSString *const UIColorCollection = @"UIColorCollection";
+NSString *const UIColorKeyThemeEnabled = @"UIColorKeyThemeEnabled";
+
 @implementation UIColor (OWS)
 
 #pragma mark - Global App Colors
@@ -338,6 +343,26 @@ NS_ASSUME_NONNULL_BEGIN
     return [self.ows_conversationColorMap allKeysForObject:color].firstObject;
 }
 
+#pragma mark - Theme
+
++ (BOOL)isThemeEnabled
+{
+    OWSAssertIsOnMainThread();
+
+    return [OWSPrimaryStorage.sharedManager.dbReadConnection boolForKey:UIColorKeyThemeEnabled
+                                                           inCollection:UIColorCollection
+                                                           defaultValue:NO];
+}
+
++ (void)setIsThemeEnabled:(BOOL)value
+{
+    OWSAssertIsOnMainThread();
+
+    [OWSPrimaryStorage.sharedManager.dbReadWriteConnection setBool:value
+                                                            forKey:UIColorKeyThemeEnabled
+                                                      inCollection:UIColorCollection];
+}
+
 @end
 
 NS_ASSUME_NONNULL_END

SignalMessaging/utils/OWSPreferences.h

@@ -61,9 +61,6 @@ extern NSString *const OWSPreferencesCallLoggingDidChangeNotification;
 - (BOOL)hasGeneratedThumbnails;
 - (void)setHasGeneratedThumbnails:(BOOL)value;
 
-- (BOOL)isThemeEnabled;
-- (void)setIsThemeEnabled:(BOOL)flag;
-
 #pragma mark Callkit
 
 - (BOOL)isSystemCallLogEnabled;

SignalMessaging/utils/OWSPreferences.m

@@ -31,7 +31,6 @@ NSString *const OWSPreferencesKeyHasGeneratedThumbnails = @"OWSPreferencesKeyHas
 NSString *const OWSPreferencesKeyIOSUpgradeNagDate = @"iOSUpgradeNagDate";
 NSString *const OWSPreferencesKey_IsReadyForAppExtensions = @"isReadyForAppExtensions_5";
 NSString *const OWSPreferencesKeySystemCallLogEnabled = @"OWSPreferencesKeySystemCallLogEnabled";
-NSString *const OWSPreferencesKeyEnableTheme = @"OWSPreferencesKeyEnableTheme";
 
 @implementation OWSPreferences
 
@@ -414,19 +413,6 @@ NSString *const OWSPreferencesKeyEnableTheme = @"OWSPreferencesKeyEnableTheme";
     }
 }
 
-- (BOOL)isThemeEnabled
-{
-    NSNumber *preference = [self tryGetValueForKey:OWSPreferencesKeyEnableTheme];
-    return preference ? [preference boolValue] : NO;
-}
-
-- (void)setIsThemeEnabled:(BOOL)flag
-{
-    OWSAssert(CurrentAppContext().isMainApp);
-
-    [self setValueForKey:OWSPreferencesKeyEnableTheme toValue:@(flag)];
-}
-
 #pragma mark - Push Tokens
 
 - (void)setPushToken:(NSString *)value