diff --git a/src/v2/pages/V2CaseStudy.jsx b/src/v2/pages/V2CaseStudy.jsx
index 9ded442..b05f170 100644
--- a/src/v2/pages/V2CaseStudy.jsx
+++ b/src/v2/pages/V2CaseStudy.jsx
@@ -1,6 +1,5 @@
 import { useReducer, useEffect } from 'react';
 import { useParams, useHistory } from 'react-router-dom';
-import UserExamService from '../../services/UserExamService';
 import CustomPreloader from '../../components/custom/CustomPreloader';
 import '../styles/v2-theme.css';
 
diff --git a/src/v2/pages/V2CouponCenter.jsx b/src/v2/pages/V2CouponCenter.jsx
index 10fe313..982a375 100644
--- a/src/v2/pages/V2CouponCenter.jsx
+++ b/src/v2/pages/V2CouponCenter.jsx
@@ -1,6 +1,8 @@
 import { useState, useEffect } from 'react';
 import { useHistory } from 'react-router-dom';
 import CouponService from '../../services/CouponService';
+import Util from '../../commons/Util';
+import CustomPreloader from '../../components/custom/CustomPreloader';
 import '../styles/v2-theme.css';
 
 const V2CouponCenter = () => {
@@ -27,36 +29,35 @@ const V2CouponCenter = () => {
 
     const copyToClipboard = (code) => {
         navigator.clipboard.writeText(code);
-        // Toast logic could be added here if a global toast exists
+        Util.showToast('Código copiado al portapapeles');
     };
 
     return (
         <div className="v2-page-container">
             <header style={{ display: 'flex', alignItems: 'center', gap: '16px', marginBottom: '32px' }}>
-                <button className="v2-btn-tonal" onClick={() => history.goBack()} style={{ borderRadius: '50%', width: '40px', height: '40px', padding: 0 }}>
-                    <i className="material-icons">arrow_back</i>
+                <button
+                    className="v2-btn-tonal"
+                    onClick={() => history.goBack()}
+                    style={{ borderRadius: '50%', width: '40px', height: '40px', padding: 0 }}
+                    aria-label="Volver"
+                >
+                    <i className="material-icons" aria-hidden="true">arrow_back</i>
                 </button>
                 <h1 className="v2-headline-small">Centro de Cupones</h1>
             </header>
 
             {loading ? (
                 <div className="center-align" style={{ padding: '40px' }}>
-                    <div className="preloader-wrapper big active">
-                        <div className="spinner-layer spinner-green-only">
-                            <div className="circle-clipper left"><div className="circle"></div></div>
-                            <div className="gap-patch"><div className="circle"></div></div>
-                            <div className="circle-clipper right"><div className="circle"></div></div>
-                        </div>
-                    </div>
+                    <CustomPreloader color="green" size="big" />
                 </div>
             ) : error ? (
                 <div className="v2-card center-align" style={{ padding: '32px' }}>
-                    <i className="material-icons" style={{ fontSize: '48px', color: 'var(--md-sys-color-error)', marginBottom: '16px' }}>error_outline</i>
+                    <i className="material-icons" style={{ fontSize: '48px', color: 'var(--md-sys-color-error)', marginBottom: '16px' }} aria-hidden="true">error_outline</i>
                     <p className="v2-body-large">{error}</p>
                 </div>
             ) : coupons.length === 0 ? (
                 <div className="v2-card center-align" style={{ padding: '32px' }}>
-                    <i className="material-icons" style={{ fontSize: '48px', opacity: 0.5, marginBottom: '16px' }}>confirmation_number</i>
+                    <i className="material-icons" style={{ fontSize: '48px', opacity: 0.5, marginBottom: '16px' }} aria-hidden="true">confirmation_number</i>
                     <p className="v2-body-large">No tienes cupones disponibles en este momento.</p>
                 </div>
             ) : (
@@ -76,12 +77,12 @@ const V2CouponCenter = () => {
                             <div className="v2-label-small" style={{ opacity: 0.7 }}>Vence: {coupon.expires}</div>
 
                             <button
-                                className="v2-btn-primary"
+                                className="v2-btn-filled"
                                 style={{ width: '100%', marginTop: '24px' }}
                                 disabled={coupon.status === 'expired'}
                                 onClick={() => copyToClipboard(coupon.code)}
                             >
-                                <i className="material-icons" style={{ marginRight: '8px' }}>content_copy</i>
+                                <i className="material-icons" style={{ marginRight: '8px' }} aria-hidden="true">content_copy</i>
                                 Copiar Código
                             </button>
                         </div>
diff --git a/src/v2/pages/V2CouponCenter.test.jsx b/src/v2/pages/V2CouponCenter.test.jsx
index 713c6ed..c08c21a 100644
--- a/src/v2/pages/V2CouponCenter.test.jsx
+++ b/src/v2/pages/V2CouponCenter.test.jsx
@@ -20,6 +20,9 @@ vi.mock('../../services/CouponService');
 describe('V2CouponCenter', () => {
   beforeEach(() => {
     vi.clearAllMocks();
+    if (globalThis.M && globalThis.M.toast) {
+      globalThis.M.toast.mockClear();
+    }
   });
 
   it('renders loading state initially', () => {
@@ -29,7 +32,7 @@ describe('V2CouponCenter', () => {
         <V2CouponCenter />
       </MemoryRouter>
     );
-    expect(document.querySelector('.preloader-wrapper')).toBeTruthy();
+    expect(screen.getByRole('progressbar')).toBeTruthy();
   });
 
   it('renders coupons after loading', async () => {
@@ -51,7 +54,7 @@ describe('V2CouponCenter', () => {
     });
   });
 
-  it('handles copy to clipboard', async () => {
+  it('handles copy to clipboard and shows toast', async () => {
     const mockClipboard = {
       writeText: vi.fn().mockResolvedValue(undefined),
     };
@@ -73,5 +76,18 @@ describe('V2CouponCenter', () => {
     fireEvent.click(copyButton);
 
     expect(mockClipboard.writeText).toHaveBeenCalledWith('PROMO2025');
+    expect(globalThis.M.toast).toHaveBeenCalledWith({ html: 'Código copiado al portapapeles' });
+  });
+
+  it('handles go back button', async () => {
+    CouponService.getCoupons.mockResolvedValue({ data: [] });
+    render(
+      <MemoryRouter>
+        <V2CouponCenter />
+      </MemoryRouter>
+    );
+    const backButton = screen.getByLabelText('Volver');
+    fireEvent.click(backButton);
+    expect(mockGoBack).toHaveBeenCalled();
   });
 });
diff --git a/src/v2/pages/V2FlashcardStudy.jsx b/src/v2/pages/V2FlashcardStudy.jsx
index df190e6..50a813a 100644
--- a/src/v2/pages/V2FlashcardStudy.jsx
+++ b/src/v2/pages/V2FlashcardStudy.jsx
@@ -14,6 +14,7 @@ const V2FlashcardStudy = () => {
 
     const handleAnswer = (quality) => {
         // En una implementación real, aquí se llamaría al backend con la calidad del SRS
+        console.log('Quality:', quality);
         if (currentIndex < flashcards.length - 1) {
             setCurrentIndex(currentIndex + 1);
             setShowAnswer(false);