Support dark mode in auth flow

Auth/FirebaseAuthUI/FUIAuthTableViewCell.m

@@ -18,6 +18,15 @@
 
 @implementation FUIAuthTableViewCell
 
+- (void)awakeFromNib {
+  [super awakeFromNib];
+
+  if (@available(iOS 13.0, *)) {
+    self.textField.textColor = [UIColor labelColor];
+    self.label.textColor = [UIColor labelColor];
+  }
+}
+
 - (void)setLabel:(UILabel *)label {
   _label = label;
   [self layoutIfNeeded];

Auth/FirebaseAuthUI/FUIPrivacyAndTermsOfServiceView.m

@@ -60,8 +60,14 @@ - (NSAttributedString *)privacyPolicyAndTOSMessageFromFormat:(NSString *)format
   NSString *privacyPolicyString = FUILocalizedString(kStr_PrivacyPolicy);
   NSString *privacyPolicyAndTOSString =
       [NSString stringWithFormat:format, termsOfServiceString, privacyPolicyString];
-  NSMutableAttributedString *attributedLinkText =
-      [[NSMutableAttributedString alloc] initWithString:privacyPolicyAndTOSString];
+  NSMutableAttributedString *attributedLinkText = nil;
+
+  if (@available(iOS 13.0, *)) {
+    attributedLinkText = [[NSMutableAttributedString alloc] initWithString:privacyPolicyAndTOSString
+                                                                attributes:@{NSForegroundColorAttributeName: [UIColor labelColor]}];
+  } else {
+    attributedLinkText = [[NSMutableAttributedString alloc] initWithString:privacyPolicyAndTOSString];
+  }
 
   NSRange TOSRange = [privacyPolicyAndTOSString rangeOfString:termsOfServiceString];
   if (TOSRange.length) {

EmailAuth/FirebaseEmailAuthUI/FUIPasswordRecoveryViewController.m

@@ -94,6 +94,11 @@ - (void)viewDidLoad {
   self.navigationItem.rightBarButtonItem = sendButtonItem;
 
   [self enableDynamicCellHeightForTableView:_tableView];
+
+  if (@available(iOS 13.0, *)) {
+    _tableView.backgroundColor = [UIColor systemBackgroundColor];
+    self.footerTextView.textColor = [UIColor secondaryLabelColor];
+  }
 }
 
 - (void)viewDidLayoutSubviews {

EmailAuth/FirebaseEmailAuthUI/FUIPasswordSignInViewController.m

@@ -111,6 +111,10 @@ - (void)viewDidLoad {
   [_termsOfServiceView useFooterMessage];
 
   [self enableDynamicCellHeightForTableView:_tableView];
+
+  if (@available(iOS 13.0, *)) {
+    _tableView.backgroundColor = [UIColor systemBackgroundColor];
+  }
 }
 
 - (void)viewWillAppear:(BOOL)animated {

EmailAuth/FirebaseEmailAuthUI/FUIPasswordSignUpViewController.m

@@ -127,6 +127,10 @@ - (void)viewDidLoad {
   self.navigationItem.rightBarButtonItem = saveButtonItem;
 
   [self enableDynamicCellHeightForTableView:_tableView];
+
+  if (@available(iOS 13.0, *)) {
+    _tableView.backgroundColor = [UIColor systemBackgroundColor];
+  }
 }
 
 - (void)viewDidLayoutSubviews {