diff --git a/packages/shared/src/components/modals/post/CommentModal.spec.tsx b/packages/shared/src/components/modals/post/CommentModal.spec.tsx
new file mode 100644
index 00000000000..1c7b8991eea
--- /dev/null
+++ b/packages/shared/src/components/modals/post/CommentModal.spec.tsx
@@ -0,0 +1,181 @@
+import React, { type ReactNode } from 'react';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { render, screen } from '@testing-library/react';
+import CommentModal from './CommentModal';
+import Post from '../../../../__tests__/fixture/post';
+import loggedUser from '../../../../__tests__/fixture/loggedUser';
+import { useAuthContext } from '../../../contexts/AuthContext';
+import useCommentById from '../../../hooks/comments/useCommentById';
+import { useNotificationToggle } from '../../../hooks/notifications';
+import { useMutateComment } from '../../../hooks/post/useMutateComment';
+
+jest.mock('../common/Modal', () => {
+  const mockReact = jest.requireActual('react') as typeof React;
+
+  const MockModalBody = mockReact.forwardRef<
+    HTMLElement,
+    { children: ReactNode; className?: string }
+  >(({ children, className }, ref) => (
+    <section className={className} data-testid="modal-body" ref={ref}>
+      {children}
+    </section>
+  ));
+
+  MockModalBody.displayName = 'MockModalBody';
+
+  const Modal = ({ children }: { children: ReactNode }) => (
+    <div data-testid="modal">{children}</div>
+  );
+
+  Modal.Body = MockModalBody;
+
+  return { Modal };
+});
+
+jest.mock('../../comments/CommentContainer', () => ({
+  __esModule: true,
+  default: () => <div data-testid="comment-container" />,
+}));
+
+jest.mock('../../fields/Switch', () => {
+  const mockReact = jest.requireActual('react') as typeof React;
+
+  const MockSwitch = mockReact.forwardRef<
+    HTMLLabelElement,
+    {
+      children: ReactNode;
+      className?: string;
+      labelClassName?: string;
+    }
+  >(({ children, className, labelClassName }, ref) => (
+    <label
+      className={className}
+      data-testid="notification-switch"
+      htmlFor="notification-switch-input"
+      ref={ref}
+    >
+      <span className={labelClassName}>{children}</span>
+      <input id="notification-switch-input" type="checkbox" />
+    </label>
+  ));
+
+  MockSwitch.displayName = 'MockSwitch';
+
+  return {
+    Switch: MockSwitch,
+  };
+});
+
+jest.mock('../../fields/MarkdownInput/CommentMarkdownInput', () => {
+  const mockReact = jest.requireActual('react') as typeof React;
+
+  const MockCommentMarkdownInput = mockReact.forwardRef<
+    HTMLFormElement,
+    {
+      className?: Record<string, string>;
+      formProps?: Record<string, string>;
+    }
+  >(({ className, formProps }, ref) => (
+    <form
+      {...formProps}
+      className={className?.container}
+      data-testid="comment-form"
+      ref={ref}
+    >
+      <div
+        className={className?.markdownContainer}
+        data-testid="markdown-container"
+      >
+        <textarea
+          aria-label="Share your thoughts"
+          className={className?.input}
+        />
+      </div>
+    </form>
+  ));
+
+  MockCommentMarkdownInput.displayName = 'MockCommentMarkdownInput';
+
+  return {
+    CommentMarkdownInput: MockCommentMarkdownInput,
+  };
+});
+
+jest.mock('../../../contexts/AuthContext', () => ({
+  useAuthContext: jest.fn(),
+}));
+
+jest.mock('../../../hooks/post/useMutateComment', () => ({
+  useMutateComment: jest.fn(),
+}));
+
+jest.mock('../../../hooks/notifications', () => ({
+  useNotificationToggle: jest.fn(),
+}));
+
+jest.mock('../../../hooks/comments/useCommentById', () => ({
+  __esModule: true,
+  default: jest.fn(),
+}));
+
+const mockUseAuthContext = useAuthContext as jest.Mock;
+const mockUseMutateComment = useMutateComment as jest.Mock;
+const mockUseNotificationToggle = useNotificationToggle as jest.Mock;
+const mockUseCommentById = useCommentById as jest.Mock;
+
+const defaultProps = {
+  isOpen: true,
+  onRequestClose: jest.fn(),
+  post: Post,
+};
+
+const renderComponent = () => {
+  const client = new QueryClient();
+
+  return render(
+    <QueryClientProvider client={client}>
+      <CommentModal {...defaultProps} />
+    </QueryClientProvider>,
+  );
+};
+
+describe('CommentModal', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    mockUseAuthContext.mockReturnValue({ user: loggedUser });
+    mockUseMutateComment.mockReturnValue({
+      mutateComment: jest.fn(),
+      isLoading: false,
+      isSuccess: false,
+    });
+    mockUseNotificationToggle.mockReturnValue({
+      shouldShowCta: true,
+      isEnabled: true,
+      onToggle: jest.fn(),
+      onSubmitted: jest.fn(),
+    });
+    mockUseCommentById.mockReturnValue({ comment: null });
+  });
+
+  it('should keep the mobile modal background on the scroll surface', () => {
+    renderComponent();
+
+    expect(screen.getByTestId('modal-body')).toHaveClass(
+      'bg-background-default',
+    );
+  });
+
+  it('should keep the editor and notification switch in the normal flex flow', () => {
+    renderComponent();
+
+    const commentForm = screen.getByTestId('comment-form');
+
+    expect(commentForm).toHaveClass('flex', 'min-h-0');
+    expect(screen.getByTestId('markdown-container')).toHaveClass(
+      'min-h-0',
+      'flex-1',
+    );
+    expect(screen.getByTestId('notification-switch')).toBeInTheDocument();
+    expect(commentForm).not.toHaveAttribute('style');
+  });
+});
diff --git a/packages/shared/src/components/modals/post/CommentModal.tsx b/packages/shared/src/components/modals/post/CommentModal.tsx
index f25a984414a..c307be759de 100644
--- a/packages/shared/src/components/modals/post/CommentModal.tsx
+++ b/packages/shared/src/components/modals/post/CommentModal.tsx
@@ -1,11 +1,5 @@
 import type { ReactElement } from 'react';
-import React, {
-  useCallback,
-  useLayoutEffect,
-  useMemo,
-  useRef,
-  useState,
-} from 'react';
+import React, { useCallback, useLayoutEffect, useMemo, useState } from 'react';
 import type { QueryClient } from '@tanstack/react-query';
 import { useQueryClient } from '@tanstack/react-query';
 import classNames from 'classnames';
@@ -15,7 +9,6 @@ import { FormWrapper } from '../../fields/form';
 import type { CommentMarkdownInputProps } from '../../fields/MarkdownInput/CommentMarkdownInput';
 import { CommentMarkdownInput } from '../../fields/MarkdownInput/CommentMarkdownInput';
 import { useMutateComment } from '../../../hooks/post/useMutateComment';
-import { useVisualViewport } from '../../../hooks/utils/useVisualViewport';
 import type { Comment, PostCommentsData } from '../../../graphql/comments';
 import { useNotificationToggle } from '../../../hooks/notifications';
 import { NotificationPromptSource } from '../../../lib/log';
@@ -79,7 +72,6 @@ const getCommentFromCache = ({
 
   return undefined;
 };
-
 export interface CommentModalProps
   extends LazyModalCommonProps,
     CommentMarkdownInputProps {
@@ -97,11 +89,6 @@ export default function CommentModal({
   post,
   initialContent: initialContentFromProps,
 }: CommentModalProps): ReactElement {
-  const inputRef = useRef<HTMLFormElement>(null);
-  const headerRef = useRef<HTMLDivElement>(null);
-  const replyRef = useRef<HTMLDivElement>(null);
-  const switchRef = useRef<HTMLLabelElement>(null);
-
   const { user } = useAuthContext();
   const client = useQueryClient();
   const [modalNode, setModalNode] = useState<HTMLElement>(null);
@@ -166,20 +153,6 @@ export default function CommentModal({
     modalNode?.scrollTo?.({ behavior: 'auto', top: 10000 });
   }, [modalNode]);
 
-  const { height } = useVisualViewport();
-  const replyHeight = replyRef.current?.clientHeight ?? 0;
-  const footerHeight = switchRef.current?.clientHeight ?? 0;
-  const headerHeight = headerRef.current?.offsetHeight ?? 0;
-  const totalHeight = height - headerHeight - replyHeight - footerHeight;
-  const inputHeight = totalHeight > 0 ? Math.max(totalHeight, 300) : 'auto';
-
-  if (
-    inputRef.current &&
-    inputRef.current.style?.height !== `${inputHeight}px`
-  ) {
-    inputRef.current.style.height = `${inputHeight}px`;
-  }
-
   const { submitCopy, initialContent } = useMemo(() => {
     if (isEdit) {
       return {
@@ -217,7 +190,7 @@ export default function CommentModal({
       className="!border-none"
       overlayClassName="!touch-none"
     >
-      <Modal.Body className="!p-0" ref={refCallback}>
+      <Modal.Body className="bg-background-default !p-0" ref={refCallback}>
         <WriteCommentContext.Provider
           value={{ mutateComment: mutateCommentResult }}
         >
@@ -235,10 +208,10 @@ export default function CommentModal({
               disabled: isSuccess,
             }}
             className={{
-              container: 'flex-1 first:!border-none',
+              container:
+                'flex min-h-full flex-1 flex-col bg-background-default first:!border-none',
               header: 'sticky top-0 z-2 w-full bg-background-default',
             }}
-            headerRef={headerRef}
           >
             {isReply && comment && (
               <>
@@ -251,10 +224,7 @@ export default function CommentModal({
                   postAuthorId={post?.author?.id}
                   postScoutId={post?.scout?.id}
                 />
-                <div
-                  className="ml-12 flex gap-2 border-l border-border-subtlest-tertiary py-3 pl-5 text-text-tertiary typo-caption1"
-                  ref={replyRef}
-                >
+                <div className="ml-12 flex gap-2 border-l border-border-subtlest-tertiary py-3 pl-5 text-text-tertiary typo-caption1">
                   Reply to
                   <span className="font-bold text-text-primary">
                     {comment.author?.username}
@@ -263,16 +233,15 @@ export default function CommentModal({
               </>
             )}
             <CommentMarkdownInput
-              ref={inputRef}
               replyTo={null}
               post={post}
               parentCommentId={parentCommentId}
               editCommentId={isEdit && editCommentId}
               initialContent={initialContent}
               className={{
-                markdownContainer: 'flex-1',
+                markdownContainer: 'min-h-0 flex-1',
                 container: classNames(
-                  'flex flex-col',
+                  'flex min-h-0 flex-col',
                   isReply ? 'h-[calc(100%-2.5rem)]' : 'h-full',
                 ),
                 tab: 'flex-1',
@@ -291,7 +260,6 @@ export default function CommentModal({
                 compact={false}
                 checked={isEnabled}
                 onToggle={onToggle}
-                ref={switchRef}
               >
                 Receive updates when other members engage
               </Switch>