diff --git a/src/app/components/event-readers/EventReaders.tsx b/src/app/components/event-readers/EventReaders.tsx
index c7900237..72b188ce 100644
--- a/src/app/components/event-readers/EventReaders.tsx
+++ b/src/app/components/event-readers/EventReaders.tsx
@@ -24,6 +24,7 @@ import { useMediaAuthentication } from '../../hooks/useMediaAuthentication';
 import { useOpenUserRoomProfile } from '../../state/hooks/userRoomProfile';
 import { useSpaceOptionally } from '../../hooks/useSpace';
 import { getMouseEventCords } from '../../utils/dom';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 export type EventReadersProps = {
   room: Room;
@@ -52,7 +53,7 @@ export const EventReaders = as<'div', EventReadersProps>(
           <Box grow="Yes">
             <Text size="H3">Seen by</Text>
           </Box>
-          <IconButton size="300" onClick={requestClose}>
+          <IconButton className={PhoneHit} size="300" onClick={requestClose}>
             <Icon src={Icons.Cross} />
           </IconButton>
         </Header>
diff --git a/src/app/components/invite-user-prompt/InviteUserPrompt.tsx b/src/app/components/invite-user-prompt/InviteUserPrompt.tsx
index ddac0576..a503fe13 100644
--- a/src/app/components/invite-user-prompt/InviteUserPrompt.tsx
+++ b/src/app/components/invite-user-prompt/InviteUserPrompt.tsx
@@ -42,6 +42,7 @@ import { AsyncStatus, useAsyncCallback } from '../../hooks/useAsyncCallback';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { BreakWord } from '../../styles/Text.css';
 import { useAlive } from '../../hooks/useAlive';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 const SEARCH_OPTIONS: UseAsyncSearchOptions = {
   limit: 1000,
@@ -173,7 +174,7 @@ export function InviteUserPrompt({ room, requestClose }: InviteUserProps) {
                   </Text>
                 </Box>
                 <Box shrink="No">
-                  <IconButton size="300" radii="300" onClick={requestClose}>
+                  <IconButton className={PhoneHit} size="300" radii="300" onClick={requestClose}>
                     <Icon src={Icons.Cross} />
                   </IconButton>
                 </Box>
diff --git a/src/app/components/join-address-prompt/JoinAddressPrompt.tsx b/src/app/components/join-address-prompt/JoinAddressPrompt.tsx
index 50a89418..ffd5241c 100644
--- a/src/app/components/join-address-prompt/JoinAddressPrompt.tsx
+++ b/src/app/components/join-address-prompt/JoinAddressPrompt.tsx
@@ -20,6 +20,7 @@ import { stopPropagation } from '../../utils/keyboard';
 import { isRoomAlias, isRoomId } from '../../utils/matrix';
 import { parseMatrixToRoom, parseMatrixToRoomEvent, testMatrixTo } from '../../plugins/matrix-to';
 import { tryDecodeURIComponent } from '../../utils/dom';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 type JoinAddressProps = {
   onOpen: (roomIdOrAlias: string, via?: string[], eventId?: string) => void;
@@ -82,7 +83,7 @@ export function JoinAddressPrompt({ onOpen, onCancel }: JoinAddressProps) {
               <Box grow="Yes">
                 <Text size="H4">Join with Address</Text>
               </Box>
-              <IconButton size="300" onClick={onCancel} radii="300">
+              <IconButton className={PhoneHit} size="300" onClick={onCancel} radii="300">
                 <Icon src={Icons.Cross} />
               </IconButton>
             </Header>
diff --git a/src/app/components/leave-room-prompt/LeaveRoomPrompt.tsx b/src/app/components/leave-room-prompt/LeaveRoomPrompt.tsx
index 217491e6..832dd59d 100644
--- a/src/app/components/leave-room-prompt/LeaveRoomPrompt.tsx
+++ b/src/app/components/leave-room-prompt/LeaveRoomPrompt.tsx
@@ -20,6 +20,7 @@ import { MatrixError } from 'matrix-js-sdk';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { AsyncStatus, useAsyncCallback } from '../../hooks/useAsyncCallback';
 import { stopPropagation } from '../../utils/keyboard';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 type LeaveRoomPromptProps = {
   roomId: string;
@@ -68,7 +69,7 @@ export function LeaveRoomPrompt({ roomId, onDone, onCancel }: LeaveRoomPromptPro
               <Box grow="Yes">
                 <Text size="H4">Leave Room</Text>
               </Box>
-              <IconButton size="300" onClick={onCancel} radii="300">
+              <IconButton className={PhoneHit} size="300" onClick={onCancel} radii="300">
                 <Icon src={Icons.Cross} />
               </IconButton>
             </Header>
diff --git a/src/app/components/leave-space-prompt/LeaveSpacePrompt.tsx b/src/app/components/leave-space-prompt/LeaveSpacePrompt.tsx
index 8709b942..6c75ef99 100644
--- a/src/app/components/leave-space-prompt/LeaveSpacePrompt.tsx
+++ b/src/app/components/leave-space-prompt/LeaveSpacePrompt.tsx
@@ -20,6 +20,7 @@ import { MatrixError } from 'matrix-js-sdk';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { AsyncStatus, useAsyncCallback } from '../../hooks/useAsyncCallback';
 import { stopPropagation } from '../../utils/keyboard';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 type LeaveSpacePromptProps = {
   roomId: string;
@@ -68,7 +69,7 @@ export function LeaveSpacePrompt({ roomId, onDone, onCancel }: LeaveSpacePromptP
               <Box grow="Yes">
                 <Text size="H4">Leave Space</Text>
               </Box>
-              <IconButton size="300" onClick={onCancel} radii="300">
+              <IconButton className={PhoneHit} size="300" onClick={onCancel} radii="300">
                 <Icon src={Icons.Cross} />
               </IconButton>
             </Header>
diff --git a/src/app/components/room-topic-viewer/RoomTopicViewer.tsx b/src/app/components/room-topic-viewer/RoomTopicViewer.tsx
index 52128772..0d091e7e 100644
--- a/src/app/components/room-topic-viewer/RoomTopicViewer.tsx
+++ b/src/app/components/room-topic-viewer/RoomTopicViewer.tsx
@@ -4,6 +4,7 @@ import classNames from 'classnames';
 import Linkify from 'linkify-react';
 import * as css from './style.css';
 import { LINKIFY_OPTS, scaleSystemEmoji } from '../../plugins/react-custom-html-parser';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 export const RoomTopicViewer = as<
   'div',
@@ -26,7 +27,7 @@ export const RoomTopicViewer = as<
           {name}
         </Text>
       </Box>
-      <IconButton size="300" onClick={requestClose} radii="300">
+      <IconButton className={PhoneHit} size="300" onClick={requestClose} radii="300">
         <Icon src={Icons.Cross} />
       </IconButton>
     </Header>
diff --git a/src/app/components/user-profile/PowerChip.tsx b/src/app/components/user-profile/PowerChip.tsx
index a6758300..d3e9cf28 100644
--- a/src/app/components/user-profile/PowerChip.tsx
+++ b/src/app/components/user-profile/PowerChip.tsx
@@ -43,6 +43,7 @@ import { getPowerTagIconSrc, useGetMemberPowerTag } from '../../hooks/useMemberP
 import { useRoomCreators } from '../../hooks/useRoomCreators';
 import { useRoomPermissions } from '../../hooks/useRoomPermissions';
 import { useMemberPowerCompare } from '../../hooks/useMemberPowerCompare';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 type SelfDemoteAlertProps = {
   power: number;
@@ -70,7 +71,7 @@ function SelfDemoteAlert({ power, onCancel, onChange }: SelfDemoteAlertProps) {
               <Box grow="Yes">
                 <Text size="H4">Self Demotion</Text>
               </Box>
-              <IconButton size="300" onClick={onCancel} radii="300">
+              <IconButton className={PhoneHit} size="300" onClick={onCancel} radii="300">
                 <Icon src={Icons.Cross} />
               </IconButton>
             </Header>
@@ -120,7 +121,7 @@ function SharedPowerAlert({ power, onCancel, onChange }: SharedPowerAlertProps)
               <Box grow="Yes">
                 <Text size="H4">Shared Power</Text>
               </Box>
-              <IconButton size="300" onClick={onCancel} radii="300">
+              <IconButton className={PhoneHit} size="300" onClick={onCancel} radii="300">
                 <Icon src={Icons.Cross} />
               </IconButton>
             </Header>
diff --git a/src/app/features/add-existing/AddExisting.tsx b/src/app/features/add-existing/AddExisting.tsx
index d100096b..a57a6b10 100644
--- a/src/app/features/add-existing/AddExisting.tsx
+++ b/src/app/features/add-existing/AddExisting.tsx
@@ -54,6 +54,7 @@ import { StateEvent } from '../../../types/matrix/room';
 import { getViaServers } from '../../plugins/via-servers';
 import { rateLimitedActions } from '../../utils/matrix';
 import { useAlive } from '../../hooks/useAlive';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 const SEARCH_OPTS: UseAsyncSearchOptions = {
   limit: 500,
@@ -201,7 +202,7 @@ export function AddExistingModal({ parentId, space, requestClose }: AddExistingM
                   <Text size="H4">Add Existing</Text>
                 </Box>
                 <Box shrink="No">
-                  <IconButton size="300" radii="300" onClick={requestClose}>
+                  <IconButton className={PhoneHit} size="300" radii="300" onClick={requestClose}>
                     <Icon src={Icons.Cross} />
                   </IconButton>
                 </Box>
diff --git a/src/app/features/create-room/CreateRoomModal.tsx b/src/app/features/create-room/CreateRoomModal.tsx
index d5d8c92d..9332f35c 100644
--- a/src/app/features/create-room/CreateRoomModal.tsx
+++ b/src/app/features/create-room/CreateRoomModal.tsx
@@ -24,6 +24,7 @@ import {
 import { CreateRoomModalState } from '../../state/createRoomModal';
 import { stopPropagation } from '../../utils/keyboard';
 import { CreateRoomType } from '../../components/create-room/types';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 type CreateRoomModalProps = {
   state: CreateRoomModalState;
@@ -63,7 +64,7 @@ function CreateRoomModal({ state }: CreateRoomModalProps) {
                     </Text>
                   </Box>
                   <Box shrink="No">
-                    <IconButton size="300" radii="300" onClick={closeDialog}>
+                    <IconButton className={PhoneHit} size="300" radii="300" onClick={closeDialog}>
                       <Icon src={Icons.Cross} />
                     </IconButton>
                   </Box>
diff --git a/src/app/features/create-space/CreateSpaceModal.tsx b/src/app/features/create-space/CreateSpaceModal.tsx
index c1bc6898..faa53b25 100644
--- a/src/app/features/create-space/CreateSpaceModal.tsx
+++ b/src/app/features/create-space/CreateSpaceModal.tsx
@@ -23,6 +23,7 @@ import {
 } from '../../state/hooks/createSpaceModal';
 import { CreateSpaceModalState } from '../../state/createSpaceModal';
 import { stopPropagation } from '../../utils/keyboard';
+import { PhoneHit } from '../../styles/PhoneHit.css';
 
 type CreateSpaceModalProps = {
   state: CreateSpaceModalState;
@@ -61,7 +62,7 @@ function CreateSpaceModal({ state }: CreateSpaceModalProps) {
                     <Text size="H4">New Space</Text>
                   </Box>
                   <Box shrink="No">
-                    <IconButton size="300" radii="300" onClick={closeDialog}>
+                    <IconButton className={PhoneHit} size="300" radii="300" onClick={closeDialog}>
                       <Icon src={Icons.Cross} />
                     </IconButton>
                   </Box>
diff --git a/src/app/phoneHit.dialogs.test.ts b/src/app/phoneHit.dialogs.test.ts
new file mode 100644
index 00000000..8b3416a5
--- /dev/null
+++ b/src/app/phoneHit.dialogs.test.ts
@@ -0,0 +1,28 @@
+import { describe, it } from 'vitest';
+import { expectPhoneHitClasses, expectSizeTie } from './phoneHitTestKit';
+
+// Dialog and prompt close buttons: each is a 32 px button (24 px Icon + 8 px padding) alone at the end of a
+// header whose title is not tappable, so the plain PhoneHit; no neighbour to spread from, no clipping container.
+describe('icon buttons in dialogs and prompts', () => {
+  const expected: Record<string, string[]> = {
+    'features/create-space/CreateSpaceModal.tsx': ['PhoneHit'],
+    'features/create-room/CreateRoomModal.tsx': ['PhoneHit'],
+    'features/add-existing/AddExisting.tsx': ['PhoneHit'],
+    'components/room-topic-viewer/RoomTopicViewer.tsx': ['PhoneHit'],
+    'components/leave-room-prompt/LeaveRoomPrompt.tsx': ['PhoneHit'],
+    'components/leave-space-prompt/LeaveSpacePrompt.tsx': ['PhoneHit'],
+    'components/event-readers/EventReaders.tsx': ['PhoneHit'],
+    'components/invite-user-prompt/InviteUserPrompt.tsx': ['PhoneHit'],
+    'components/join-address-prompt/JoinAddressPrompt.tsx': ['PhoneHit'], // join cancel
+    'components/user-profile/PowerChip.tsx': ['PhoneHit', 'PhoneHit'], // self demotion, shared power
+  };
+
+  it.each(Object.entries(expected))(
+    '%s: each IconButton carries its own PhoneHit class',
+    (file, want) => expectPhoneHitClasses(file, want)
+  );
+
+  it.each(Object.keys(expected))('%s: a sized variant matches the drawn size', (file) =>
+    expectSizeTie(file)
+  );
+});