* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --accent-color: #0ea5e9;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-light: #94a3b8;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --border-color: #e2e8f0;
    --border-light: #f1f5f9;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
.header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav {
    padding: 1rem 0;
}

.nav .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.25rem;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s ease;
}

.nav-links a:hover,
.nav-links a:focus {
    color: var(--primary-color);
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-menu-btn span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all 0.3s ease;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: all 0.2s ease;
    cursor: pointer;
    border: none;
    min-height: 44px;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover,
.btn-primary:focus {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover,
.btn-secondary:focus {
    background: var(--bg-tertiary);
    border-color: var(--primary-color);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn-outline:hover,
.btn-outline:focus {
    background: var(--primary-color);
    color: white;
}

.btn-success {
    background: var(--success-color);
    color: white;
}

.btn-success:hover,
.btn-success:focus {
    background: #059669;
}

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

/* Hero Section */
.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-content h1 {
    font-size: 3rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.hero-content p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.6;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.hero-image img {
    width: 100%;
    height: auto;
    border-radius: var(--radius-lg);
}

/* Features Section */
.features {
    padding: 5rem 0;
    background: var(--bg-primary);
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    text-align: center;
    border: 1px solid var(--border-light);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

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

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Featured Courses */
.featured-courses {
    padding: 5rem 0;
    background: var(--bg-secondary);
}

.featured-courses h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.course-card {
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    border: 1px solid var(--border-color);
}

.course-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.course-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.course-content {
    padding: 1.5rem;
}

.course-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.course-category {
    background: var(--accent-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
}

.course-difficulty {
    color: var(--text-light);
    font-size: 0.875rem;
}

.course-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.course-title a {
    text-decoration: none;
    color: inherit;
}

.course-title a:hover {
    color: var(--primary-color);
}

.course-description {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.5;
}

.course-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.course-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.course-duration {
    color: var(--text-light);
    font-size: 0.875rem;
}

.section-footer {
    text-align: center;
}

/* Trust Section */
.trust-section {
    padding: 5rem 0;
    background: var(--bg-primary);
}

.trust-section h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.trust-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.trust-item {
    text-align: center;
    padding: 2rem;
}

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

.trust-item h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.trust-item p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Course Detail Page */
.course-detail {
    padding: 2rem 0;
}

.course-header {
    background: var(--bg-secondary);
    padding: 3rem 0;
    margin-bottom: 3rem;
}

.course-header .container {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
    align-items: start;
}

.course-info h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.course-info p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.6;
}

.course-stats {
    display: flex;
    gap: 2rem;
    margin-bottom: 2rem;
}

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

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    display: block;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-light);
}

.course-sidebar {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    position: sticky;
    top: 100px;
}

.course-image-large {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: var(--radius-md);
    margin-bottom: 1.5rem;
}

.price-section {
    text-align: center;
    margin-bottom: 2rem;
}

.current-price {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
}

.course-includes {
    margin-bottom: 2rem;
}

.course-includes h4 {
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.course-includes ul {
    list-style: none;
}

.course-includes li {
    padding: 0.5rem 0;
    color: var(--text-secondary);
    position: relative;
    padding-left: 1.5rem;
}

.course-includes li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: 600;
}

.course-content-section {
    background: var(--bg-primary);
    padding: 3rem 0;
}

.content-tabs {
    display: flex;
    gap: 2rem;
    margin-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
}

.tab-button {
    background: none;
    border: none;
    padding: 1rem 0;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: all 0.2s ease;
}

.tab-button.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.curriculum-list {
    list-style: none;
}

.curriculum-item {
    background: var(--bg-secondary);
    padding: 1.5rem;
    margin-bottom: 1rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-light);
}

.curriculum-item h4 {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.curriculum-item p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.instructor-card {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-light);
}

.instructor-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.instructor-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

.faq-list {
    list-style: none;
}

.faq-item {
    margin-bottom: 1.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.faq-question {
    background: var(--bg-secondary);
    padding: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border: none;
    width: 100%;
    text-align: left;
}

.faq-question::after {
    content: '+';
    font-size: 1.5rem;
    font-weight: 300;
    transition: transform 0.2s ease;
}

.faq-question.active::after {
    transform: rotate(45deg);
}

.faq-answer {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
}

.faq-answer.active {
    padding: 1.5rem;
    max-height: 200px;
}

.faq-answer p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Courses Page */
.courses-page {
    padding: 2rem 0;
}

.courses-header {
    background: var(--bg-secondary);
    padding: 3rem 0;
    margin-bottom: 3rem;
}

.courses-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.courses-header p {
    text-align: center;
    font-size: 1.25rem;
    color: var(--text-secondary);
}

.courses-filters {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    margin-bottom: 3rem;
}

.filters-row {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 1rem;
    align-items: end;
}

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

.filter-group label {
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.filter-group input,
.filter-group select {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    background: var(--bg-primary);
    color: var(--text-primary);
}

.filter-group input:focus,
.filter-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgb(37 99 235 / 0.1);
}

.courses-results {
    margin-bottom: 2rem;
}

.results-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.results-count {
    color: var(--text-secondary);
}

.clear-filters {
    background: none;
    border: none;
    color: var(--primary-color);
    text-decoration: underline;
    cursor: pointer;
    font-size: 0.875rem;
}

/* Checkout Pages */
.checkout {
    padding: 2rem 0;
    background: var(--bg-secondary);
    min-height: 80vh;
}

.checkout-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 1rem;
}

.checkout-header {
    text-align: center;
    margin-bottom: 3rem;
}

.checkout-header h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.checkout-steps {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 3rem;
}

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-light);
}

.step.active {
    color: var(--primary-color);
}

.step.completed {
    color: var(--success-color);
}

.step-number {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.875rem;
}

.step.active .step-number {
    background: var(--primary-color);
    color: white;
}

.step.completed .step-number {
    background: var(--success-color);
    color: white;
}

.checkout-form {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.form-section {
    margin-bottom: 2rem;
}

.form-section h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    margin-bottom: 1rem;
}

.form-group.full-width {
    grid-column: 1 / -1;
}

.form-group label {
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgb(37 99 235 / 0.1);
}

.form-group input.error,
.form-group select.error {
    border-color: var(--error-color);
}

.error-message {
    color: var(--error-color);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.checkout-summary {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-light);
    margin-bottom: 2rem;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-light);
}

.summary-item:last-child {
    border-bottom: none;
    font-weight: 600;
    font-size: 1.125rem;
}

.payment-methods {
    display: flex;
    gap: 1rem;
    align-items: center;
    margin-bottom: 1rem;
}

.payment-icon {
    width: 40px;
    height: 24px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.security-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: 1rem;
}

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    margin-bottom: 2rem;
}

.checkbox-group input[type="checkbox"] {
    margin: 0;
    margin-top: 0.125rem;
}

.checkbox-group label {
    margin: 0;
    line-height: 1.5;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.checkbox-group a {
    color: var(--primary-color);
    text-decoration: none;
}

.checkbox-group a:hover {
    text-decoration: underline;
}

.checkout-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
}

.back-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
}

.back-link:hover {
    color: var(--primary-color);
}

/* Order Success */
.order-success {
    padding: 3rem 0;
    text-align: center;
}

.success-icon {
    font-size: 4rem;
    color: var(--success-color);
    margin-bottom: 2rem;
}

.order-success h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.order-success p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.order-details {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-light);
    text-align: left;
    max-width: 600px;
    margin: 0 auto 3rem;
}

.order-details h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.detail-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-light);
}

.detail-row:last-child {
    border-bottom: none;
    font-weight: 600;
}

/* Content Pages */
.content-page {
    padding: 2rem 0;
}

.content-header {
    background: var(--bg-secondary);
    padding: 3rem 0;
    margin-bottom: 3rem;
}

.content-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.content-header p {
    text-align: center;
    font-size: 1.25rem;
    color: var(--text-secondary);
}

.content-body {
    max-width: 800px;
    margin: 0 auto;
    line-height: 1.8;
}

.content-body h2 {
    font-size: 2rem;
    font-weight: 600;
    margin: 2rem 0 1rem;
    color: var(--text-primary);
}

.content-body h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 1.5rem 0 0.75rem;
    color: var(--text-primary);
}

.content-body p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.content-body ul,
.content-body ol {
    margin: 1rem 0;
    padding-left: 2rem;
}

.content-body li {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.content-body a {
    color: var(--primary-color);
    text-decoration: none;
}

.content-body a:hover {
    text-decoration: underline;
}

/* Contact Form */
.contact-form {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-light);
    margin-bottom: 3rem;
}

.contact-info {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.contact-info h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.contact-item:last-child {
    margin-bottom: 0;
}

.contact-icon {
    font-size: 1.25rem;
    color: var(--primary-color);
}

.contact-item a {
    color: var(--primary-color);
    text-decoration: none;
}

.contact-item a:hover {
    text-decoration: underline;
}

/* FAQ Page */
.faq-search {
    max-width: 600px;
    margin: 0 auto 3rem;
}

.faq-search input {
    width: 100%;
    padding: 1rem;
    font-size: 1.125rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    background: var(--bg-primary);
}

.faq-categories {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 3rem;
}

.category-filter {
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    color: var(--text-secondary);
    font-weight: 500;
}

.category-filter:hover,
.category-filter.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 5rem;
}

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

.footer-section h4 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: #cbd5e1;
    text-decoration: none;
    transition: color 0.2s ease;
}

.footer-section a:hover {
    color: white;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.footer-section p {
    color: #cbd5e1;
    line-height: 1.6;
}

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 2rem;
    text-align: center;
    color: #9ca3af;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }

    .nav-links {
        display: none;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .hero .container {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }

    .hero-content h1 {
        font-size: 2rem;
    }

    .hero-content p {
        font-size: 1rem;
    }

    .hero-actions {
        justify-content: center;
    }

    .features h2,
    .featured-courses h2,
    .trust-section h2 {
        font-size: 2rem;
    }

    .features-grid,
    .courses-grid {
        grid-template-columns: 1fr;
    }

    .course-header .container {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .course-sidebar {
        position: static;
        order: -1;
    }

    .filters-row {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .form-grid {
        grid-template-columns: 1fr;
    }

    .checkout-steps {
        gap: 1rem;
    }

    .step-text {
        display: none;
    }

    .checkout-actions {
        flex-direction: column-reverse;
        align-items: stretch;
    }

    .content-tabs {
        flex-wrap: wrap;
        gap: 1rem;
    }

    .results-info {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 1.75rem;
    }

    .course-card {
        margin: 0 -0.5rem;
    }

    .checkout-container {
        padding: 0 0.5rem;
    }

    .checkout-form {
        padding: 1rem;
    }

    .btn {
        padding: 0.75rem 1rem;
        font-size: 0.875rem;
    }
}

/* Focus and accessibility */
*:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

button:focus,
input:focus,
select:focus,
textarea:focus,
a:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Screen reader only */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Loading states */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid #f3f3f3;
    border-top: 2px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}