* {
    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 {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: #6366f1;
    font-weight: 700;
    font-size: 1.25rem;
}

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

.nav-link {
    text-decoration: none;
    color: #64748b;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-link:hover,
.nav-link.active {
    color: #6366f1;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    border-radius: 0.5rem;
    font-weight: 600;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    text-align: center;
}

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

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

.btn-secondary {
    background: transparent;
    color: #6366f1;
    border: 2px solid #6366f1;
}

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

.btn-outline {
    background: transparent;
    color: #64748b;
    border: 2px solid #e2e8f0;
}

.btn-outline:hover {
    border-color: #6366f1;
    color: #6366f1;
}

/* Hero Section */
.hero {
    position: relative;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 6rem 0;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: url('/assets/hero-bg.svg');
    background-size: cover;
    background-position: center;
    opacity: 0.1;
}

.hero-content {
    position: relative;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2.5rem;
    opacity: 0.9;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Trust Section */
.trust-section {
    padding: 4rem 0;
    background: #f8fafc;
}

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

.trust-item {
    text-align: center;
    padding: 2rem;
    background: white;
    border-radius: 1rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

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

.trust-item h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: #1e293b;
}

.trust-item p {
    color: #64748b;
}

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

.featured-courses h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 3rem;
    color: #1e293b;
}

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

.course-card {
    background: white;
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: transform 0.3s, box-shadow 0.3s;
    text-decoration: none;
    color: inherit;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px rgba(0,0,0,0.1);
}

.course-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: #f1f5f9;
}

.course-content {
    padding: 1.5rem;
}

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

.course-category {
    background: #e0e7ff;
    color: #6366f1;
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 500;
}

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

.course-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: #1e293b;
}

.course-description {
    color: #64748b;
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

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

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

.course-price {
    font-size: 1.25rem;
    font-weight: 700;
    color: #6366f1;
}

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

/* Features */
.features {
    padding: 5rem 0;
    background: #f8fafc;
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 3rem;
    color: #1e293b;
}

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

.feature {
    text-align: center;
    padding: 2rem;
    background: white;
    border-radius: 1rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

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

.feature h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #1e293b;
}

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

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

.course-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
}

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

.course-info h1 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.course-info p {
    font-size: 1.1rem;
    opacity: 0.9;
    margin-bottom: 1.5rem;
}

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

.stat {
    text-align: center;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
}

.stat-label {
    font-size: 0.875rem;
    opacity: 0.8;
}

.course-purchase {
    background: rgba(255,255,255,0.1);
    padding: 2rem;
    border-radius: 1rem;
    text-align: center;
}

.price {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.course-tabs {
    margin: 3rem 0;
}

.tabs {
    display: flex;
    border-bottom: 2px solid #e2e8f0;
    margin-bottom: 2rem;
}

.tab {
    padding: 1rem 2rem;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    color: #64748b;
    border-bottom: 2px solid transparent;
    transition: all 0.3s;
}

.tab.active {
    color: #6366f1;
    border-bottom-color: #6366f1;
}

.tab-content {
    display: none;
}

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

.curriculum-item {
    background: #f8fafc;
    padding: 1rem;
    border-radius: 0.5rem;
    margin-bottom: 0.5rem;
}

.faq-item {
    background: #f8fafc;
    padding: 1.5rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
}

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

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

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

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

.form-input {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #e5e7eb;
    border-radius: 0.5rem;
    font-size: 1rem;
    transition: border-color 0.3s;
}

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

.form-input.error {
    border-color: #ef4444;
}

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

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

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    margin: 1rem 0;
}

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

/* Checkout */
.checkout {
    padding: 2rem 0;
}

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

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

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 9999px;
    background: #f1f5f9;
    color: #64748b;
}

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

.checkout-content {
    max-width: 600px;
    margin: 0 auto;
}

.payment-icons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin: 1rem 0;
}

.payment-icon {
    width: 40px;
    height: 24px;
}

.order-summary {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 1rem;
    margin-bottom: 2rem;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.summary-total {
    display: flex;
    justify-content: space-between;
    font-weight: 700;
    font-size: 1.25rem;
    padding-top: 1rem;
    border-top: 2px solid #e2e8f0;
}

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

.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: #e2e8f0;
}

.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;
}

.footer-section a:hover {
    color: #6366f1;
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero-cta {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-cta .btn {
        width: 200px;
    }
    
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .course-header-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .tabs {
        flex-wrap: wrap;
        gap: 0.5rem;
    }
    
    .tab {
        padding: 0.75rem 1rem;
    }
    
    .form-grid {
        grid-template-columns: 1fr;
    }
    
    .checkout-steps {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 4rem 0;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .features h2,
    .featured-courses h2 {
        font-size: 2rem;
    }
}

/* Focus states for accessibility */
.btn:focus,
.form-input:focus,
.tab:focus {
    outline: 2px solid #6366f1;
    outline-offset: 2px;
}

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

/* Search and filter */
.search-filters {
    background: #f8fafc;
    padding: 2rem 0;
    margin-bottom: 2rem;
}

.search-bar {
    max-width: 500px;
    margin: 0 auto 2rem;
    position: relative;
}

.search-input {
    width: 100%;
    padding: 1rem;
    border: 2px solid #e5e7eb;
    border-radius: 0.5rem;
    font-size: 1rem;
}

.filters {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.filter-select {
    padding: 0.5rem 1rem;
    border: 2px solid #e5e7eb;
    border-radius: 0.5rem;
    background: white;
    cursor: pointer;
}