diff --git a/native/account/logged-out-modal.react.js b/native/account/logged-out-modal.react.js
--- a/native/account/logged-out-modal.react.js
+++ b/native/account/logged-out-modal.react.js
@@ -249,7 +249,7 @@
   +loggedIn: boolean,
   +dimensions: DerivedDimensionsInfo,
   +splashStyle: ImageStyle,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Redux dispatch functions
   +dispatch: Dispatch,
   // Keyserver olm sessions functions
diff --git a/native/calendar/calendar.react.js b/native/calendar/calendar.react.js
--- a/native/calendar/calendar.react.js
+++ b/native/calendar/calendar.react.js
@@ -174,7 +174,7 @@
   +loadingStatus: LoadingStatus,
   +connectionStatus: ConnectionStatus,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +indicatorStyle: IndicatorStyle,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
diff --git a/native/calendar/entry.react.js b/native/calendar/entry.react.js
--- a/native/calendar/entry.react.js
+++ b/native/calendar/entry.react.js
@@ -200,7 +200,7 @@
   // Redux state
   +calendarQuery: () => CalendarQuery,
   +online: boolean,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Nav state
   +threadPickerActive: boolean,
   +navigateToThread: (params: MessageListParams) => void,
diff --git a/native/calendar/section-footer.react.js b/native/calendar/section-footer.react.js
--- a/native/calendar/section-footer.react.js
+++ b/native/calendar/section-footer.react.js
@@ -45,7 +45,7 @@
 type Props = {
   ...BaseProps,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
 };
 class SectionFooter extends React.PureComponent<Props> {
   render(): React.Node {
diff --git a/native/chat/chat-input-bar.react.js b/native/chat/chat-input-bar.react.js
--- a/native/chat/chat-input-bar.react.js
+++ b/native/chat/chat-input-bar.react.js
@@ -289,7 +289,7 @@
   +nextLocalID: string,
   +userInfos: UserInfos,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +onInputBarLayout?: (event: LayoutEvent) => mixed,
   +openCamera: () => mixed,
   +isActive: boolean,
diff --git a/native/chat/failed-send.react.js b/native/chat/failed-send.react.js
--- a/native/chat/failed-send.react.js
+++ b/native/chat/failed-send.react.js
@@ -44,7 +44,7 @@
 type Props = {
   ...BaseProps,
   +rawMessageInfo: ?RawComposableMessageInfo,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +inputState: ?InputState,
   +parentThreadInfo: ?ThreadInfo,
 };
diff --git a/native/chat/message-list-container.react.js b/native/chat/message-list-container.react.js
--- a/native/chat/message-list-container.react.js
+++ b/native/chat/message-list-container.react.js
@@ -93,7 +93,7 @@
   +genesisThreadInfo: ?ThreadInfo | ?MinimallyEncodedThreadInfo,
   +messageListData: ?$ReadOnlyArray<NativeChatMessageItem>,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // withOverlayContext
   +overlayContext: ?OverlayContextType,
   +measureMessages: MessagesMeasurer,
diff --git a/native/chat/message-list-header-title.react.js b/native/chat/message-list-header-title.react.js
--- a/native/chat/message-list-header-title.react.js
+++ b/native/chat/message-list-header-title.react.js
@@ -39,7 +39,7 @@
 };
 type Props = {
   ...BaseProps,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +title: string,
 };
 class MessageListHeaderTitle extends React.PureComponent<Props> {
diff --git a/native/chat/message-list.react.js b/native/chat/message-list.react.js
--- a/native/chat/message-list.react.js
+++ b/native/chat/message-list.react.js
@@ -77,7 +77,7 @@
 type Props = {
   ...BaseProps,
   +startReached: boolean,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +indicatorStyle: IndicatorStyle,
   +dispatchActionPromise: DispatchActionPromise,
   +fetchMessagesBeforeCursor: (
diff --git a/native/chat/settings/color-selector-modal.react.js b/native/chat/settings/color-selector-modal.react.js
--- a/native/chat/settings/color-selector-modal.react.js
+++ b/native/chat/settings/color-selector-modal.react.js
@@ -70,7 +70,7 @@
   ...BaseProps,
   // Redux state
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +windowWidth: number,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
diff --git a/native/chat/settings/compose-subchannel-modal.react.js b/native/chat/settings/compose-subchannel-modal.react.js
--- a/native/chat/settings/compose-subchannel-modal.react.js
+++ b/native/chat/settings/compose-subchannel-modal.react.js
@@ -66,7 +66,7 @@
 type Props = {
   ...BaseProps,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
 };
 class ComposeSubchannelModal extends React.PureComponent<Props> {
   render(): React.Node {
diff --git a/native/chat/settings/delete-thread.react.js b/native/chat/settings/delete-thread.react.js
--- a/native/chat/settings/delete-thread.react.js
+++ b/native/chat/settings/delete-thread.react.js
@@ -122,7 +122,7 @@
   +shouldUseDeleteConfirmationAlert: boolean,
   +loadingStatus: LoadingStatus,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
diff --git a/native/chat/settings/thread-settings-color.react.js b/native/chat/settings/thread-settings-color.react.js
--- a/native/chat/settings/thread-settings-color.react.js
+++ b/native/chat/settings/thread-settings-color.react.js
@@ -51,7 +51,7 @@
   // Redux state
   +loadingStatus: LoadingStatus,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
 };
 class ThreadSettingsColor extends React.PureComponent<Props> {
   render(): React.Node {
diff --git a/native/chat/settings/thread-settings-description.react.js b/native/chat/settings/thread-settings-description.react.js
--- a/native/chat/settings/thread-settings-description.react.js
+++ b/native/chat/settings/thread-settings-description.react.js
@@ -100,7 +100,7 @@
   // Redux state
   +loadingStatus: LoadingStatus,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
diff --git a/native/chat/settings/thread-settings-home-notifs.react.js b/native/chat/settings/thread-settings-home-notifs.react.js
--- a/native/chat/settings/thread-settings-home-notifs.react.js
+++ b/native/chat/settings/thread-settings-home-notifs.react.js
@@ -47,7 +47,7 @@
 type Props = {
   ...BaseProps,
   // Redux state
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
diff --git a/native/chat/settings/thread-settings-leave-thread.react.js b/native/chat/settings/thread-settings-leave-thread.react.js
--- a/native/chat/settings/thread-settings-leave-thread.react.js
+++ b/native/chat/settings/thread-settings-leave-thread.react.js
@@ -58,7 +58,7 @@
   +loadingStatus: LoadingStatus,
   +otherUsersButNoOtherAdmins: boolean,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
diff --git a/native/chat/settings/thread-settings-list-action.react.js b/native/chat/settings/thread-settings-list-action.react.js
--- a/native/chat/settings/thread-settings-list-action.react.js
+++ b/native/chat/settings/thread-settings-list-action.react.js
@@ -66,7 +66,7 @@
   +iconSize: number,
   +iconStyle?: TextStyle,
   +buttonStyle?: ViewStyle,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
 };
 function ThreadSettingsListAction(props: ListActionProps) {
   return (
diff --git a/native/chat/settings/thread-settings-member.react.js b/native/chat/settings/thread-settings-member.react.js
--- a/native/chat/settings/thread-settings-member.react.js
+++ b/native/chat/settings/thread-settings-member.react.js
@@ -109,7 +109,7 @@
   +removeUserLoadingStatus: LoadingStatus,
   +changeRoleLoadingStatus: LoadingStatus,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // withKeyboardState
   +keyboardState: ?KeyboardState,
   // withOverlayContext
diff --git a/native/chat/settings/thread-settings-name.react.js b/native/chat/settings/thread-settings-name.react.js
--- a/native/chat/settings/thread-settings-name.react.js
+++ b/native/chat/settings/thread-settings-name.react.js
@@ -72,7 +72,7 @@
   // Redux state
   +loadingStatus: LoadingStatus,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
diff --git a/native/chat/settings/thread-settings-promote-sidebar.react.js b/native/chat/settings/thread-settings-promote-sidebar.react.js
--- a/native/chat/settings/thread-settings-promote-sidebar.react.js
+++ b/native/chat/settings/thread-settings-promote-sidebar.react.js
@@ -38,7 +38,7 @@
   ...BaseProps,
   +loadingStatus: LoadingStatus,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +promoteSidebar: () => mixed,
 };
 class ThreadSettingsPromoteSidebar extends React.PureComponent<Props> {
diff --git a/native/chat/settings/thread-settings-push-notifs.react.js b/native/chat/settings/thread-settings-push-notifs.react.js
--- a/native/chat/settings/thread-settings-push-notifs.react.js
+++ b/native/chat/settings/thread-settings-push-notifs.react.js
@@ -59,7 +59,7 @@
 type Props = {
   ...BaseProps,
   // Redux state
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
diff --git a/native/chat/settings/thread-settings.react.js b/native/chat/settings/thread-settings.react.js
--- a/native/chat/settings/thread-settings.react.js
+++ b/native/chat/settings/thread-settings.react.js
@@ -276,7 +276,7 @@
   +parentThreadInfo: ?ResolvedThreadInfo | ?MinimallyEncodedResolvedThreadInfo,
   +childThreadInfos: ?$ReadOnlyArray<ResolvedThreadInfo>,
   +somethingIsSaving: boolean,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +indicatorStyle: IndicatorStyle,
   // withOverlayContext
   +overlayContext: ?OverlayContextType,
@@ -758,7 +758,7 @@
           | ?ResolvedThreadInfo
           | ?MinimallyEncodedResolvedThreadInfo,
         navigate: ThreadSettingsNavigate,
-        styles: typeof unboundStyles,
+        styles: $ReadOnly<typeof unboundStyles>,
         userInfos: UserInfos,
         viewerID: ?string,
       ) => {
diff --git a/native/chat/thread-settings-button.react.js b/native/chat/thread-settings-button.react.js
--- a/native/chat/thread-settings-button.react.js
+++ b/native/chat/thread-settings-button.react.js
@@ -24,7 +24,7 @@
 };
 type Props = {
   ...BaseProps,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
 };
 
 class ThreadSettingsButton extends React.PureComponent<Props> {
diff --git a/native/components/link-button.react.js b/native/components/link-button.react.js
--- a/native/components/link-button.react.js
+++ b/native/components/link-button.react.js
@@ -26,7 +26,7 @@
 };
 type Props = {
   ...BaseProps,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
 };
 class LinkButton extends React.PureComponent<Props> {
   render(): React.Node {
diff --git a/native/components/thread-list-thread.react.js b/native/components/thread-list-thread.react.js
--- a/native/components/thread-list-thread.react.js
+++ b/native/components/thread-list-thread.react.js
@@ -40,7 +40,7 @@
   ...SharedProps,
   +threadInfo: ResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
 };
 class ThreadListThread extends React.PureComponent<Props> {
   render(): React.Node {
diff --git a/native/components/thread-list.react.js b/native/components/thread-list.react.js
--- a/native/components/thread-list.react.js
+++ b/native/components/thread-list.react.js
@@ -35,7 +35,7 @@
 type Props = {
   ...BaseProps,
   // Redux state
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +indicatorStyle: IndicatorStyle,
 };
 type State = {
diff --git a/native/components/user-list-user.react.js b/native/components/user-list-user.react.js
--- a/native/components/user-list-user.react.js
+++ b/native/components/user-list-user.react.js
@@ -46,7 +46,7 @@
   ...BaseProps,
   // Redux state
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
 };
 class UserListUser extends React.PureComponent<Props> {
   render(): React.Node {
diff --git a/native/keyboard/keyboard-input-host.react.js b/native/keyboard/keyboard-input-host.react.js
--- a/native/keyboard/keyboard-input-host.react.js
+++ b/native/keyboard/keyboard-input-host.react.js
@@ -29,7 +29,7 @@
 type Props = {
   ...BaseProps,
   // Redux state
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +activeMessageList: ?string,
   // withKeyboardState
   +keyboardState: KeyboardState,
diff --git a/native/media/media-gallery-keyboard.react.js b/native/media/media-gallery-keyboard.react.js
--- a/native/media/media-gallery-keyboard.react.js
+++ b/native/media/media-gallery-keyboard.react.js
@@ -111,7 +111,7 @@
   +dimensions: DimensionsInfo,
   +foreground: boolean,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
 };
 type State = {
   +selections: ?$ReadOnlyArray<MediaLibrarySelection>,
diff --git a/native/profile/appearance-preferences.react.js b/native/profile/appearance-preferences.react.js
--- a/native/profile/appearance-preferences.react.js
+++ b/native/profile/appearance-preferences.react.js
@@ -89,7 +89,7 @@
   +route: NavigationRoute<'AppearancePreferences'>,
   +globalThemeInfo: GlobalThemeInfo,
   +updateThemePreference: (themePreference: GlobalThemePreference) => mixed,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +colors: Colors,
 };
 class AppearancePreferences extends React.PureComponent<Props> {
diff --git a/native/profile/custom-server-modal.react.js b/native/profile/custom-server-modal.react.js
--- a/native/profile/custom-server-modal.react.js
+++ b/native/profile/custom-server-modal.react.js
@@ -62,7 +62,7 @@
   ...BaseProps,
   +urlPrefix: string,
   +customServer: ?string,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +dispatch: Dispatch,
 };
 type State = {
diff --git a/native/profile/default-notifications-preferences.react.js b/native/profile/default-notifications-preferences.react.js
--- a/native/profile/default-notifications-preferences.react.js
+++ b/native/profile/default-notifications-preferences.react.js
@@ -89,7 +89,7 @@
 
 type Props = {
   ...BaseProps,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +dispatchActionPromise: DispatchActionPromise,
   +changeNotificationSettings: (
     notificationSettingsRequest: UpdateUserSettingsRequest,
diff --git a/native/profile/dev-tools.react.js b/native/profile/dev-tools.react.js
--- a/native/profile/dev-tools.react.js
+++ b/native/profile/dev-tools.react.js
@@ -98,7 +98,7 @@
   +urlPrefix: string,
   +customServer: ?string,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +dispatch: Dispatch,
 };
 class DevTools extends React.PureComponent<Props> {
diff --git a/native/profile/edit-password.react.js b/native/profile/edit-password.react.js
--- a/native/profile/edit-password.react.js
+++ b/native/profile/edit-password.react.js
@@ -99,7 +99,7 @@
   +loadingStatus: LoadingStatus,
   +username: ?string,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
diff --git a/native/profile/profile-screen.react.js b/native/profile/profile-screen.react.js
--- a/native/profile/profile-screen.react.js
+++ b/native/profile/profile-screen.react.js
@@ -153,7 +153,7 @@
   +preRequestUserState: PreRequestUserState,
   +logOutLoading: boolean,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +dispatchActionPromise: DispatchActionPromise,
   +logOut: (preRequestUserState: PreRequestUserState) => Promise<LogOutResult>,
   +staffCanSee: boolean,
diff --git a/native/profile/relationship-list-item.react.js b/native/profile/relationship-list-item.react.js
--- a/native/profile/relationship-list-item.react.js
+++ b/native/profile/relationship-list-item.react.js
@@ -105,7 +105,7 @@
   // Redux state
   +removeUserLoadingStatus: LoadingStatus,
   +colors: Colors,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
diff --git a/native/themes/colors.js b/native/themes/colors.js
--- a/native/themes/colors.js
+++ b/native/themes/colors.js
@@ -277,7 +277,7 @@
 type Styles = { [name: string]: { [field: string]: mixed } };
 
 type ReplaceField = (input: any) => any;
-export type StyleSheetOf<S: Styles> = $ObjMap<S, ReplaceField>;
+export type StyleSheetOf<S: Styles> = $ReadOnly<$ObjMap<S, ReplaceField>>;
 
 function stylesFromColors<IS: Styles>(
   obj: IS,
diff --git a/native/tooltip/tooltip.react.js b/native/tooltip/tooltip.react.js
--- a/native/tooltip/tooltip.react.js
+++ b/native/tooltip/tooltip.react.js
@@ -147,7 +147,7 @@
   +dimensions: DimensionsInfo,
   +overlayContext: ?OverlayContextType,
   +chatContext: ?ChatContextType,
-  +styles: typeof unboundStyles,
+  +styles: $ReadOnly<typeof unboundStyles>,
   +tooltipContext: TooltipContextType,
   +closeTooltip: () => mixed,
   +boundTooltipItem: React.ComponentType<TooltipItemBaseProps>,