/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

/* Landing Page Styles */
.landing-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.landing-header {
    padding: 1rem 0;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    text-decoration: none;
}

.auth-nav {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.auth-link {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    transition: background-color 0.3s ease;
}

.auth-link:hover {
    background: rgba(255, 255, 255, 0.1);
}

.auth-btn {
    background: white;
    color: #667eea;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.auth-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.landing-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 4rem 2rem;
}

.hero-section {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
    margin-bottom: 4rem;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    color: white;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.highlight {
    background: linear-gradient(45deg, #ffd89b 0%, #19547b 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 3rem;
}

.stats-preview {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-bottom: 3rem;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: #ffd89b;
    margin-bottom: 0.5rem;
}

.stat-label {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.9rem;
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    align-items: center;
}

.primary-btn {
    background: linear-gradient(45deg, #ffd89b 0%, #19547b 100%);
    color: white;
    padding: 1rem 2rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

.secondary-btn {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    padding: 1rem 2rem;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 12px;
    transition: all 0.3s ease;
}

.secondary-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.5);
}

.features-section {
    max-width: 1000px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    padding: 2rem;
    border-radius: 16px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-4px);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    color: white;
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.feature-card p {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.5;
}

.landing-footer {
    text-align: center;
    padding: 2rem;
    color: rgba(255, 255, 255, 0.7);
}

/* Authentication Styles */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.auth-card {
    background: white;
    border-radius: 16px;
    padding: 3rem;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 400px;
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.auth-header h2 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
    color: #333;
}

.auth-header p {
    color: #666;
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #333;
}

.form-group input {
    padding: 1rem;
    border: 2px solid #e1e5e9;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-hint {
    color: #666;
    font-size: 0.85rem;
    margin-top: 0.25rem;
}

.error-message {
    background: #fee;
    color: #c53030;
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid #fed7d7;
    font-size: 0.9rem;
}

.auth-submit-btn {
    background: linear-gradient(45deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.auth-submit-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.auth-submit-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    transform: none;
}

.auth-footer {
    text-align: center;
    margin-top: 2rem;
    color: #666;
}

.auth-footer a {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
}

/* Dashboard Styles */
.dashboard-container {
    min-height: 100vh;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
}

.dashboard-header {
    background: white;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.dashboard-header .header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-menu {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.limit-section {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 0.5rem;
}

.user-greeting {
    color: #333;
    font-weight: 500;
}

.limit-indicator {
    background: #e3f2fd;
    color: #333;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    border: 2px solid #bbdefb;
}

.limit-indicator.limit-warning {
    background: #fff3e0;
    color: #e65100;
    border-color: #ffcc02;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

.upgrade-btn-small {
    background: linear-gradient(45deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 0.4rem 0.8rem;
    border-radius: 16px;
    text-decoration: none;
    font-size: 0.75rem;
    font-weight: 600;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.upgrade-btn-small:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.pro-badge {
    background: linear-gradient(45deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.3);
}

.logout-btn {
    color: #666;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    transition: background-color 0.3s ease;
}

.logout-btn:hover {
    background: #f5f5f5;
}

.dashboard-main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.upgrade-banner {
    background: linear-gradient(135deg, #fff3e0 0%, #ffe0b2 100%);
    border: 2px solid #ffcc02;
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 4px 15px rgba(255, 204, 2, 0.2);
}

.banner-content {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.banner-icon {
    font-size: 2rem;
    flex-shrink: 0;
}

.banner-text {
    flex: 1;
}

.banner-text h3 {
    color: #e65100;
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.banner-text p {
    color: #bf360c;
    margin: 0;
}

.banner-upgrade-btn {
    background: linear-gradient(45deg, #ff9800 0%, #f57c00 100%);
    color: white;
    padding: 1rem 1.5rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    flex-shrink: 0;
}

.banner-upgrade-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 152, 0, 0.4);
}

.stats-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.stat-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    text-align: center;
    transition: transform 0.2s ease;
}

.stat-card:hover {
    transform: translateY(-2px);
}

.stat-card .stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: #667eea;
    margin-bottom: 0.5rem;
}

.stat-card .stat-label {
    color: #666;
    font-weight: 500;
}

.generate-section {
    background: white;
    padding: 3rem;
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    margin-bottom: 3rem;
}

.generate-section h2 {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    color: #333;
}

.generate-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.generate-form textarea {
    min-height: 150px;
    padding: 1.5rem;
    border: 2px solid #e1e5e9;
    border-radius: 12px;
    font-size: 1rem;
    resize: vertical;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.generate-form textarea:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.generate-btn {
    background: linear-gradient(45deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1.25rem 2rem;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.generate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.3);
}

.generation-limit-info {
    background: #f0f4ff;
    border: 1px solid #c7d2fe;
    border-radius: 8px;
    padding: 1rem;
    margin-top: 1rem;
    text-align: center;
}

.generation-limit-info p {
    margin: 0;
    color: #4338ca;
    font-size: 0.9rem;
}

.generation-limit-info a {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
}

.generation-limit-info a:hover {
    text-decoration: underline;
}

.history-section {
    background: white;
    padding: 3rem;
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.history-section h2 {
    font-size: 1.8rem;
    margin-bottom: 2rem;
    color: #333;
}

.no-history {
    text-align: center;
    color: #666;
    font-style: italic;
    padding: 2rem;
}

.history-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.history-card {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 12px;
    border: 1px solid #e1e5e9;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.history-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.history-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 0.5rem;
}

.history-date {
    color: #666;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.view-set-btn {
    background: #667eea;
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    display: inline-block;
    transition: background-color 0.3s ease;
}

.view-set-btn:hover {
    background: #5a67d8;
}

.generating-label {
    color: #ffa500;
    font-style: italic;
    font-size: 0.9rem;
}

/* Flashcard Viewer Styles */
.flashcard-container {
    min-height: 100vh;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    padding: 2rem;
}

.flashcard-header {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
}

.back-btn {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
    padding: 0.75rem 1.5rem;
    border: 2px solid #667eea;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.back-btn:hover {
    background: #667eea;
    color: white;
}

.set-title {
    font-size: 1.5rem;
    color: #333;
    font-weight: 600;
}

.progress-indicator {
    background: white;
    padding: 0.75rem 1.5rem;
    border-radius: 20px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    font-weight: 600;
    color: #667eea;
}

.flashcard-main {
    max-width: 600px;
    margin: 0 auto;
}

.flashcard-wrapper {
    perspective: 1000px;
    margin-bottom: 3rem;
}

.flashcard {
    width: 100%;
    height: 300px;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    cursor: pointer;
}

.flashcard.flipped {
    transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 16px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 2rem;
}

.flashcard-front {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.flashcard-back {
    background: linear-gradient(135deg, #ffd89b 0%, #19547b 100%);
    color: white;
    transform: rotateY(180deg);
}

.card-content {
    text-align: center;
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.card-content h3 {
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
    opacity: 0.9;
}

.card-content p {
    font-size: 1.1rem;
    line-height: 1.5;
}

.flip-hint {
    text-align: center;
    font-size: 0.85rem;
    opacity: 0.7;
    margin-top: 1rem;
}

.navigation-controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.nav-btn {
    background: white;
    color: #667eea;
    border: 2px solid #667eea;
    padding: 1rem 2rem;
    border-radius: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.nav-btn:hover:not(:disabled) {
    background: #667eea;
    color: white;
    transform: translateY(-1px);
}

.nav-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* Upgrade Page Styles */
.upgrade-container {
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 2rem;
}

.upgrade-header {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
}

.upgrade-header .back-btn {
    color: white;
    border-color: rgba(255, 255, 255, 0.5);
}

.upgrade-header .back-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: white;
}

.upgrade-header .logo {
    color: white;
}

.upgrade-main {
    max-width: 800px;
    margin: 0 auto;
}

.upgrade-card {
    background: white;
    border-radius: 20px;
    padding: 3rem;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.upgrade-hero {
    text-align: center;
    margin-bottom: 3rem;
}

.upgrade-hero h2 {
    font-size: 2.5rem;
    color: #333;
    margin-bottom: 1rem;
}

.upgrade-highlight {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    margin-top: 1.5rem;
}

.highlight-badge {
    background: linear-gradient(45deg, #ff6b6b 0%, #ee5a24 100%);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.highlight-text {
    color: #666;
    font-style: italic;
}

.pricing-section {
    margin-bottom: 3rem;
}

.price-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 2rem;
    border-radius: 16px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.price-card::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(45deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    transform: rotate(45deg);
    animation: shimmer 3s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%) translateY(-100%) rotate(45deg); }
    100% { transform: translateX(100%) translateY(100%) rotate(45deg); }
}

.price-header h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.price {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 2rem;
}

.price span {
    font-size: 1rem;
    opacity: 0.8;
}

.price-comparison {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.crossed-price {
    text-decoration: line-through;
    opacity: 0.7;
    font-size: 1.2rem;
}

.discount-badge {
    background: #ff6b6b;
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 700;
}

.features-list {
    list-style: none;
    text-align: left;
    max-width: 300px;
    margin: 0 auto;
}

.features-list li {
    padding: 0.5rem 0;
    font-size: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.payment-inquiry h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #333;
}

.payment-options {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.payment-option {
    display: block;
    cursor: pointer;
    transition: transform 0.2s ease;
}

.payment-option:hover {
    transform: translateX(4px);
}

.payment-option input[type="radio"] {
    display: none;
}

.option-content {
    display: flex;
    align-items: center;
    padding: 1.5rem;
    border: 2px solid #e1e5e9;
    border-radius: 12px;
    transition: all 0.3s ease;
    position: relative;
    background: white;
}

.option-content::after {
    content: '';
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    width: 20px;
    height: 20px;
    border: 2px solid #e1e5e9;
    border-radius: 50%;
    transition: all 0.3s ease;
}

.payment-option input[type="radio"]:checked + .option-content {
    border-color: #667eea;
    background: #f0f4ff;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.2);
}

.payment-option input[type="radio"]:checked + .option-content::after {
    background: #667eea;
    border-color: #667eea;
    box-shadow: inset 0 0 0 4px white;
}

.option-icon {
    font-size: 1.5rem;
    margin-right: 1rem;
    filter: grayscale(0.3);
    transition: filter 0.3s ease;
}

.payment-option input[type="radio"]:checked + .option-content .option-icon {
    filter: grayscale(0);
}

.option-text {
    display: flex;
    flex-direction: column;
}

.option-text strong {
    color: #333;
    margin-bottom: 0.25rem;
    font-size: 1.1rem;
}

.option-text span {
    color: #666;
    font-size: 0.9rem;
}

.payment-method-benefits {
    background: #f8f9fa;
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 2rem;
}

.payment-method-benefits h4 {
    color: #333;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.benefit-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #555;
    font-size: 0.9rem;
}

.benefit-icon {
    color: #4caf50;
    font-weight: bold;
}

.upgrade-submit-btn {
    background: linear-gradient(45deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1.25rem 2rem;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    width: 100%;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.upgrade-submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.3);
}

.confirmation-message {
    text-align: center;
    padding: 3rem;
    background: #f0fff4;
    border-radius: 16px;
    border: 2px solid #38a169;
}

.confirmation-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.confirmation-content h3 {
    color: #38a169;
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.confirmation-content p {
    color: #2d3748;
    line-height: 1.6;
}

/* Loading states */
.btn-loading {
    opacity: 0.7;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .stats-preview {
        flex-direction: column;
        gap: 1.5rem;
    }
    
    .cta-buttons {
        flex-direction: column;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .flashcard-header {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .payment-options {
        gap: 0.75rem;
    }
    
    .option-content {
        padding: 1rem;
    }
}

@media (max-width: 480px) {
    .auth-card {
        padding: 2rem;
    }
    
    .upgrade-card {
        padding: 2rem;
    }
    
    .dashboard-main {
        padding: 1rem;
    }
    
    .generate-section,
    .history-section {
        padding: 2rem;
    }
}