* {
    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-color: #fff;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background: #fff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: #2563eb;
    font-weight: 700;
    font-size: 1.25rem;
}

.nav-list {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: #64748b;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-link:hover,
.nav-link.active {
    color: #2563eb;
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-btn span {
    width: 24px;
    height: 2px;
    background: #333;
    transition: all 0.3s;
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    color: #1e293b;
}

.hero p {
    font-size: 1.25rem;
    color: #64748b;
    margin-bottom: 2rem;
}

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

.hero-image img {
    width: 100%;
    height: auto;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    text-align: center;
    transition: all 0.2s;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: #2563eb;
    color: white;
}

.btn-primary:hover {
    background: #1d4ed8;
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    color: #2563eb;
    border: 2px solid #2563eb;
}

.btn-secondary:hover {
    background: #2563eb;
    color: white;
}

/* Features Section */
.features {
    padding: 5rem 0;
    background: #fff;
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: #1e293b;
}

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

.feature-card {
    text-align: center;
    padding: 2rem;
    border-radius: 12px;
    background: #f8fafc;
    transition: transform 0.2s;
}

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

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

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #1e293b;
}

.feature-card p {
    color: #64748b;
    line-height: 1.6;
}

/* Featured Courses */
.featured-courses {
    padding: 5rem 0;
    background: #f8fafc;
}

.featured-courses h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #1e293b;
}

.section-subtitle {
    text-align: center;
    font-size: 1.25rem;
    color: #64748b;
    margin-bottom: 3rem;
}

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

.course-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.2s, box-shadow 0.2s;
    text-decoration: none;
    color: inherit;
}

.course-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.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: 0.5rem;
}

.course-category {
    background: #e0e7ff;
    color: #3730a3;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
}

.course-difficulty {
    color: #64748b;
    font-size: 0.875rem;
}

.course-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #1e293b;
}

.course-description {
    color: #64748b;
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

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

.course-price {
    font-size: 1.25rem;
    font-weight: 700;
    color: #059669;
}

.course-duration {
    color: #64748b;
    font-size: 0.875rem;
}

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

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #374151;
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: #2563eb;
}

.form-textarea {
    resize: vertical;
    min-height: 120px;
}

.form-error {
    color: #dc2626;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
}

.checkbox-group input[type="checkbox"] {
    margin-top: 0.25rem;
}

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

.course-header {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 3rem;
    margin-bottom: 3rem;
}

.course-info h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #1e293b;
}

.course-info p {
    font-size: 1.125rem;
    color: #64748b;
    margin-bottom: 2rem;
}

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

.stat {
    text-align: center;
}

.stat-value {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: #2563eb;
}

.stat-label {
    font-size: 0.875rem;
    color: #64748b;
}

.course-sidebar {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    height: fit-content;
}

.course-price-large {
    font-size: 2rem;
    font-weight: 700;
    color: #059669;
    margin-bottom: 1.5rem;
}

.course-sections {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
}

.course-main h2 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: #1e293b;
}

.course-main h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 2rem 0 1rem 0;
    color: #1e293b;
}

.course-list {
    list-style: none;
    margin-bottom: 2rem;
}

.course-list li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
}

.course-list li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #059669;
    font-weight: bold;
}

.curriculum-item {
    background: #f8fafc;
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 0.5rem;
    border-left: 4px solid #2563eb;
}

.faq-item {
    margin-bottom: 1.5rem;
}

.faq-question {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #1e293b;
}

.faq-answer {
    color: #64748b;
}

.instructor-card {
    background: #f8fafc;
    padding: 1.5rem;
    border-radius: 12px;
    margin-bottom: 2rem;
}

.instructor-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #1e293b;
}

.instructor-bio {
    color: #64748b;
}

/* Checkout */
.checkout-header {
    background: #f8fafc;
    padding: 2rem 0;
    margin-bottom: 2rem;
}

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

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.step-number {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: #e5e7eb;
    color: #64748b;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
}

.step.active .step-number {
    background: #2563eb;
    color: white;
}

.checkout-content {
    display: grid;
    grid-template-columns: 1fr 400px;
    gap: 3rem;
}

.order-summary {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    height: fit-content;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.summary-total {
    border-top: 2px solid #e5e7eb;
    padding-top: 1rem;
    font-weight: 700;
    font-size: 1.25rem;
}

.payment-icons {
    display: flex;
    gap: 0.5rem;
    margin: 1rem 0;
}

.payment-icon {
    width: 40px;
    height: 24px;
    background: #e5e7eb;
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: #64748b;
}

.security-note {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #059669;
    font-size: 0.875rem;
    margin: 1rem 0;
}

/* Footer */
.footer {
    background: #1e293b;
    color: #cbd5e1;
    padding: 3rem 0 1rem;
}

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

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
    color: white;
    font-weight: 700;
    font-size: 1.25rem;
}

.footer-section h3 {
    color: white;
    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;
}

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

.footer-bottom {
    border-top: 1px solid #334155;
    padding-top: 2rem;
    text-align: center;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-list {
        display: none;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .course-header {
        grid-template-columns: 1fr;
    }
    
    .course-sections {
        grid-template-columns: 1fr;
    }
    
    .checkout-content {
        grid-template-columns: 1fr;
    }
    
    .checkout-steps {
        flex-direction: column;
        align-items: center;
    }
}

/* Page-specific styles */
.page-header {
    background: #f8fafc;
    padding: 3rem 0;
    text-align: center;
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #1e293b;
}

.page-content {
    padding: 3rem 0;
}

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

.content-section h2 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: #1e293b;
}

.content-section h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 2rem 0 1rem 0;
    color: #1e293b;
}

.content-section p {
    margin-bottom: 1rem;
    line-height: 1.6;
    color: #64748b;
}

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

.content-section li {
    margin-bottom: 0.5rem;
    color: #64748b;
}

/* Search and Filter */
.search-filters {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    margin-bottom: 2rem;
}

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

.search-input {
    padding: 0.75rem;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    font-size: 1rem;
}

.filter-select {
    padding: 0.75rem;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    font-size: 1rem;
    min-width: 150px;
}

@media (max-width: 768px) {
    .search-row {
        grid-template-columns: 1fr;
    }
}