* {
    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: 1000;
}

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

.logo {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: #333;
    font-weight: 700;
    font-size: 1.2rem;
}

.logo img {
    margin-right: 10px;
}

.nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav a {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav a:hover {
    color: #6366f1;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background: #333;
    margin: 3px 0;
    transition: 0.3s;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 600;
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: #6366f1;
    color: white;
    border-color: #6366f1;
}

.btn-primary:hover {
    background: #5855eb;
    border-color: #5855eb;
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    color: #6366f1;
    border-color: #6366f1;
}

.btn-secondary:hover {
    background: #6366f1;
    color: white;
}

.btn-large {
    padding: 16px 32px;
    font-size: 1.1rem;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 80px 0;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

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

/* Features Section */
.features {
    padding: 80px 0;
    background: #f8fafc;
}

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

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

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
}

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

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

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

/* Featured Courses */
.featured-courses {
    padding: 80px 0;
}

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

.section-subtitle {
    text-align: center;
    font-size: 1.2rem;
    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 0.3s ease;
    text-decoration: none;
    color: inherit;
}

.course-card:hover {
    transform: translateY(-5px);
}

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

.course-content {
    padding: 1.5rem;
}

.course-tag {
    display: inline-block;
    background: #e0e7ff;
    color: #6366f1;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 1rem;
}

.course-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: #1e293b;
}

.course-card p {
    color: #64748b;
    margin-bottom: 1rem;
    line-height: 1.5;
}

.course-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    color: #64748b;
}

.course-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: #6366f1;
}

/* CTA Section */
.cta {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 80px 0;
    text-align: center;
}

.cta h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.cta p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* Footer */
.footer {
    background: #1e293b;
    color: white;
    padding: 60px 0 20px;
}

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

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
    color: #f1f5f9;
}

.footer-section p {
    color: #94a3b8;
    line-height: 1.6;
}

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

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

.footer-section a {
    color: #94a3b8;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: #f1f5f9;
}

.footer-bottom {
    border-top: 1px solid #334155;
    padding-top: 2rem;
    text-align: center;
    color: #94a3b8;
}

/* Course Detail Page */
.course-hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 60px 0;
}

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

.course-info h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.course-info .course-meta {
    margin-bottom: 1.5rem;
    color: rgba(255,255,255,0.9);
}

.course-info p {
    font-size: 1.1rem;
    opacity: 0.9;
    margin-bottom: 2rem;
}

.course-sidebar {
    background: rgba(255,255,255,0.1);
    padding: 2rem;
    border-radius: 12px;
    backdrop-filter: blur(10px);
}

.course-sidebar .course-price {
    color: white;
    margin-bottom: 1.5rem;
}

.course-details {
    padding: 80px 0;
}

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

.course-main h2 {
    color: #1e293b;
    margin-bottom: 1.5rem;
    font-size: 1.8rem;
}

.course-main ul {
    margin-bottom: 2rem;
    padding-left: 1.5rem;
}

.course-main li {
    margin-bottom: 0.5rem;
    color: #64748b;
}

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

.instructor-info h3 {
    color: #1e293b;
    margin-bottom: 1rem;
}

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

.faq-item h4 {
    color: #1e293b;
    margin-bottom: 0.5rem;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #374151;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid #d1d5db;
    border-radius: 6px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #6366f1;
}

.form-error {
    color: #ef4444;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

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

.checkbox-group input[type="checkbox"] {
    width: auto;
    margin: 0;
}

/* Checkout */
.checkout-header {
    background: #f8fafc;
    padding: 40px 0;
    text-align: center;
}

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

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    background: #e2e8f0;
    color: #64748b;
}

.step.active {
    background: #6366f1;
    color: white;
}

.checkout-content {
    padding: 60px 0;
}

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

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

.trust-badges {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin: 2rem 0;
}

.trust-badge {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: #f0f9ff;
    border-radius: 6px;
    font-size: 0.875rem;
    color: #0369a1;
}

/* Course Catalog */
.catalog-header {
    padding: 60px 0;
    background: #f8fafc;
}

.catalog-filters {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.filter-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.filter-group label {
    font-weight: 600;
    color: #374151;
}

.filter-group input,
.filter-group select {
    padding: 8px 12px;
    border: 2px solid #d1d5db;
    border-radius: 6px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .hero-content,
    .course-hero-content,
    .course-details-content,
    .checkout-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .features-grid,
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: stretch;
    }
    
    .catalog-filters {
        flex-direction: column;
    }
    
    .checkout-steps {
        flex-direction: column;
        align-items: center;
    }
}

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

.content-section {
    padding: 60px 0;
}

.page-header {
    background: #f8fafc;
    padding: 60px 0;
    text-align: center;
}

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

.page-header p {
    font-size: 1.2rem;
    color: #64748b;
}