Enhance: Add confirmation dialog system for destructive actions

.Jules/changelog.md

@@ -20,6 +20,7 @@
 - Comprehensive `EmptyState` component for Groups and Friends pages to better guide new users.
 - Toast notification system (`ToastContext`, `Toast` component) for providing non-blocking user feedback.
 - Keyboard navigation support for Groups page, enabling accessibility for power users.
+- Confirmation Dialog System (`ConfirmContext`, `ConfirmDialog`) replacing native browser alerts for destructive actions in `GroupDetails`.
 
 ### Changed
 - Updated JULES_PROMPT.md based on review of successful PRs:

.Jules/knowledge.md

@@ -205,6 +205,29 @@ addToast('Message', 'success|error|info');
 - Auto-dismisses after 3 seconds
 - Stacks vertically in bottom-right
 
+### Confirmation Dialog Pattern
+
+**Date:** 2026-01-14
+**Context:** Replacing window.confirm with custom modal
+
+```tsx
+const { confirm } = useConfirm();
+
+// In async handler
+if (await confirm({
+  title: 'Delete Item',
+  message: 'Are you sure?',
+  variant: 'danger',
+  confirmText: 'Delete'
+})) {
+  // Proceed with deletion
+}
+```
+
+- Promise-based API avoids callback hell
+- Supports `danger` and `primary` variants
+- Fully accessible with `role="dialog"`
+
 ### Form Validation Pattern
 
 **Date:** 2026-01-01

.Jules/todo.md

@@ -77,12 +77,12 @@
   - Size: ~35 lines
   - Added: 2026-01-01
 
-- [ ] **[ux]** Confirmation dialog for destructive actions
-  - Files: Create `web/components/ui/ConfirmDialog.tsx`, integrate
-  - Context: Confirm before deleting groups/expenses
-  - Impact: Prevents accidental data loss
-  - Size: ~70 lines
-  - Added: 2026-01-01
+- [x] **[ux]** Confirmation dialog for destructive actions
+  - Completed: 2026-01-14
+  - Files: `web/components/ui/ConfirmDialog.tsx`, `web/contexts/ConfirmContext.tsx`, `web/pages/GroupDetails.tsx`
+  - Context: Replaced native `window.confirm` with custom dual-theme modal
+  - Impact: Prevents accidental data loss with consistent UI
+  - Size: ~100 lines
 
 ### Mobile
 

web/App.tsx

@@ -3,6 +3,7 @@ import { HashRouter, Navigate, Route, Routes } from 'react-router-dom';
 import { Layout } from './components/layout/Layout';
 import { ThemeWrapper } from './components/layout/ThemeWrapper';
 import { AuthProvider, useAuth } from './contexts/AuthContext';
+import { ConfirmProvider } from './contexts/ConfirmContext';
 import { ThemeProvider } from './contexts/ThemeContext';
 import { ToastProvider } from './contexts/ToastContext';
 import { ToastContainer } from './components/ui/Toast';
@@ -50,14 +51,16 @@ const App = () => {
   return (
     <ThemeProvider>
       <ToastProvider>
-        <AuthProvider>
-          <HashRouter>
-              <ErrorBoundary>
-                <AppRoutes />
-              </ErrorBoundary>
-              <ToastContainer />
-          </HashRouter>
-        </AuthProvider>
+        <ConfirmProvider>
+          <AuthProvider>
+            <HashRouter>
+                <ErrorBoundary>
+                  <AppRoutes />
+                </ErrorBoundary>
+                <ToastContainer />
+            </HashRouter>
+          </AuthProvider>
+        </ConfirmProvider>
       </ToastProvider>
     </ThemeProvider>
   );

web/components/ui/ConfirmDialog.tsx

@@ -0,0 +1,44 @@
+import React from 'react';
+import { ConfirmOptions } from '../../contexts/ConfirmContext';
+import { Button } from './Button';
+import { Modal } from './Modal';
+
+interface ConfirmDialogProps {
+  isOpen: boolean;
+  onConfirm: () => void;
+  onCancel: () => void;
+  options: ConfirmOptions;
+}
+
+export const ConfirmDialog: React.FC<ConfirmDialogProps> = ({
+  isOpen,
+  onConfirm,
+  onCancel,
+  options
+}) => {
+  const { title, message, confirmText = 'Confirm', cancelText = 'Cancel', variant = 'primary' } = options;
+
+  return (
+    <Modal
+      isOpen={isOpen}
+      onClose={onCancel}
+      title={title}
+      footer={
+        <>
+          <Button variant="ghost" onClick={onCancel}>
+            {cancelText}
+          </Button>
+          <Button
+            variant={variant}
+            onClick={onConfirm}
+            autoFocus
+          >
+            {confirmText}
+          </Button>
+        </>
+      }
+    >
+      <p className="opacity-80 text-lg leading-relaxed">{message}</p>
+    </Modal>
+  );
+};

web/components/ui/Modal.tsx

@@ -53,6 +53,8 @@ export const Modal: React.FC<ModalProps> = ({ isOpen, onClose, title, children,
             onClick={onClose}
           />
           <motion.div
+            role="dialog"
+            aria-modal="true"
             variants={modalVariants}
             initial="hidden"
             animate="visible"

web/contexts/ConfirmContext.tsx

@@ -0,0 +1,67 @@
+import React, { createContext, useContext, useState, useCallback, ReactNode } from 'react';
+import { ConfirmDialog } from '../components/ui/ConfirmDialog';
+
+export interface ConfirmOptions {
+  title: string;
+  message: string;
+  confirmText?: string;
+  cancelText?: string;
+  variant?: 'danger' | 'primary';
+}
+
+interface ConfirmContextType {
+  confirm: (options: ConfirmOptions) => Promise<boolean>;
+}
+
+const ConfirmContext = createContext<ConfirmContextType | undefined>(undefined);
+
+export const useConfirm = () => {
+  const context = useContext(ConfirmContext);
+  if (!context) {
+    throw new Error('useConfirm must be used within a ConfirmProvider');
+  }
+  return context;
+};
+
+export const ConfirmProvider = ({ children }: { children: ReactNode }) => {
+  const [isOpen, setIsOpen] = useState(false);
+  const [options, setOptions] = useState<ConfirmOptions>({ title: '', message: '' });
+  const [resolveRef, setResolveRef] = useState<(value: boolean) => void>(() => {});
+
+  const confirm = useCallback((opts: ConfirmOptions) => {
+    setOptions({
+        confirmText: 'Confirm',
+        cancelText: 'Cancel',
+        variant: 'primary',
+        ...opts
+    });
+    setIsOpen(true);
+    return new Promise<boolean>((resolve) => {
+      setResolveRef(() => resolve);
+    });
+  }, []);
+
+  const handleConfirm = useCallback(() => {
+    setIsOpen(false);
+    resolveRef(true);
+  }, [resolveRef]);
+
+  const handleCancel = useCallback(() => {
+    setIsOpen(false);
+    resolveRef(false);
+  }, [resolveRef]);
+
+  return (
+    <ConfirmContext.Provider value={{ confirm }}>
+      {children}
+      {isOpen && (
+        <ConfirmDialog
+            isOpen={isOpen}
+            onConfirm={handleConfirm}
+            onCancel={handleCancel}
+            options={options}
+        />
+      )}
+    </ConfirmContext.Provider>
+  );
+};

web/pages/GroupDetails.tsx

@@ -8,6 +8,7 @@ import { Modal } from '../components/ui/Modal';
 import { Skeleton } from '../components/ui/Skeleton';
 import { THEMES } from '../constants';
 import { useAuth } from '../contexts/AuthContext';
+import { useConfirm } from '../contexts/ConfirmContext';
 import { useTheme } from '../contexts/ThemeContext';
 import { useToast } from '../contexts/ToastContext';
 import {
@@ -41,6 +42,7 @@ export const GroupDetails = () => {
     const { user } = useAuth();
     const { style } = useTheme();
     const { addToast } = useToast();
+    const { confirm } = useConfirm();
 
     const [group, setGroup] = useState<Group | null>(null);
     const [expenses, setExpenses] = useState<Expense[]>([]);
@@ -257,7 +259,12 @@ export const GroupDetails = () => {
 
     const handleDeleteExpense = async () => {
         if (!editingExpenseId || !id) return;
-        if (window.confirm("Are you sure you want to delete this expense?")) {
+        if (await confirm({
+            title: 'Delete Expense',
+            message: 'Are you sure you want to delete this expense?',
+            variant: 'danger',
+            confirmText: 'Delete'
+        })) {
             try {
                 await deleteExpense(id, editingExpenseId);
                 setIsExpenseModalOpen(false);
@@ -313,7 +320,12 @@ export const GroupDetails = () => {
 
     const handleDeleteGroup = async () => {
         if (!id) return;
-        if (window.confirm("Are you sure? This cannot be undone.")) {
+        if (await confirm({
+            title: 'Delete Group',
+            message: 'Are you sure? This cannot be undone.',
+            variant: 'danger',
+            confirmText: 'Delete Group'
+        })) {
             try {
                 await deleteGroup(id);
                 navigate('/groups');
@@ -326,7 +338,12 @@ export const GroupDetails = () => {
 
     const handleLeaveGroup = async () => {
         if (!id) return;
-        if (window.confirm("You can only leave when your balances are settled. Continue?")) {
+        if (await confirm({
+            title: 'Leave Group',
+            message: 'You can only leave when your balances are settled. Continue?',
+            variant: 'danger',
+            confirmText: 'Leave'
+        })) {
             try {
                 await leaveGroup(id);
                 addToast('You have left the group', 'success');
@@ -341,7 +358,12 @@ export const GroupDetails = () => {
         if (!id || !isAdmin) return;
         if (memberId === user?._id) return;
 
-        if (window.confirm(`Are you sure you want to remove ${memberName} from the group?`)) {
+        if (await confirm({
+            title: 'Remove Member',
+            message: `Are you sure you want to remove ${memberName} from the group?`,
+            variant: 'danger',
+            confirmText: 'Remove'
+        })) {
             try {
                 const hasUnsettled = settlements.some(
                     s => (s.fromUserId === memberId || s.toUserId === memberId) && (s.amount || 0) > 0