* {
    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;
}

.nav {
    padding: 1rem 0;
}

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

.nav-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: #333;
}

.logo, .footer-logo {
    width: 40px;
    height: 40px;
}

.brand-name, .footer-brand-name {
    font-size: 1.5rem;
    font-weight: 700;
    color: #6366f1;
}

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

.nav-link {
    text-decoration: none;
    color: #333;
    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: 5px;
}

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    text-align: center;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.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: #333;
    border: 2px solid #ddd;
}

.btn-outline:hover {
    background: #333;
    color: white;
    border-color: #333;
}

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

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

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

.hero-content p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

.hero-image img {
    width: 100%;
    height: auto;
    max-width: 500px;
}

/* 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(250px, 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;
}

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

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

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

/* Featured Courses Section */
.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: 1.125rem;
    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(0,0,0,0.05);
    transition: transform 0.3s, box-shadow 0.3s;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.1);
}

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

.course-content {
    padding: 1.5rem;
}

.course-tag {
    display: inline-block;
    padding: 4px 12px;
    background: #eff6ff;
    color: #2563eb;
    font-size: 0.875rem;
    border-radius: 20px;
    margin-bottom: 1rem;
}

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

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

.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: #059669;
    margin-bottom: 1rem;
}

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

.course-actions .btn {
    flex: 1;
    font-size: 0.9rem;
    padding: 10px 16px;
}

/* Trust Indicators */
.trust-indicators {
    padding: 80px 0;
    background: #f8fafc;
}

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

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

.trust-item {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    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;
    margin-bottom: 1rem;
    color: #1e293b;
}

/* Section Actions */
.section-actions {
    text-align: center;
}

/* Course Catalog */
.catalog-header {
    padding: 40px 0;
    background: #f8fafc;
}

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

.catalog-filters {
    padding: 40px 0;
}

.filters-row {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    align-items: center;
    margin-bottom: 2rem;
}

.search-box {
    flex: 1;
    min-width: 250px;
}

.search-input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
}

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

.filter-select {
    padding: 12px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    background: white;
    min-width: 150px;
}

.filter-select:focus {
    outline: none;
    border-color: #6366f1;
}

/* Course Detail */
.course-header {
    padding: 40px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

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

.course-detail {
    padding: 60px 0;
}

.course-detail-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 4rem;
}

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

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

.course-sidebar {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    height: fit-content;
    position: sticky;
    top: 100px;
}

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

.curriculum-list li {
    padding: 0.75rem 0;
    border-bottom: 1px solid #e2e8f0;
}

.curriculum-list li:last-child {
    border-bottom: none;
}

.requirements-list,
.learning-list {
    list-style: none;
    padding-left: 1rem;
}

.requirements-list li,
.learning-list li {
    padding: 0.5rem 0;
    position: relative;
}

.requirements-list li:before {
    content: "•";
    color: #6366f1;
    font-weight: bold;
    position: absolute;
    left: -1rem;
}

.learning-list li:before {
    content: "✓";
    color: #059669;
    font-weight: bold;
    position: absolute;
    left: -1rem;
}

.instructor-info {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    margin: 2rem 0;
}

.faq-item {
    background: #f8fafc;
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

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

/* Checkout */
.checkout-header {
    padding: 40px 0;
    background: #f8fafc;
    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: 1fr 1fr;
    gap: 4rem;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #1e293b;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
}

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

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

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

.summary-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
    border-bottom: 1px solid #e2e8f0;
}

.summary-item:last-child {
    border-bottom: none;
    font-weight: 600;
    font-size: 1.25rem;
}

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

.payment-icon {
    width: 40px;
    height: 25px;
    background: #f1f5f9;
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: bold;
    color: #64748b;
}

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    margin: 1.5rem 0;
}

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

.checkbox-group label {
    margin-bottom: 0;
    font-size: 0.9rem;
    line-height: 1.4;
}

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

.success-message {
    background: #f0fdf4;
    border: 2px solid #16a34a;
    color: #166534;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    margin: 2rem 0;
}

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

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

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

.footer-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 1rem;
}

.footer-links {
    list-style: none;
}

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

.footer-links a {
    color: #cbd5e1;
    text-decoration: none;
    transition: color 0.3s;
}

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

.contact-info p {
    margin-bottom: 0.5rem;
    color: #cbd5e1;
}

.contact-info a {
    color: #cbd5e1;
    text-decoration: none;
}

.contact-info a:hover {
    color: #f1f5f9;
}

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 2rem;
    text-align: center;
    color: #cbd5e1;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 1rem 0;
        box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-toggle {
        display: flex;
    }

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

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

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

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

    .course-detail-grid {
        grid-template-columns: 1fr;
    }

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

    .filters-row {
        flex-direction: column;
        align-items: stretch;
    }

    .search-box {
        min-width: auto;
    }

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

    .checkout-steps {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .hero {
        padding: 40px 0;
    }

    .hero-content h1 {
        font-size: 1.75rem;
    }

    .hero-actions {
        flex-direction: column;
    }

    .features,
    .featured-courses,
    .trust-indicators {
        padding: 40px 0;
    }

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

    .course-actions {
        flex-direction: column;
    }
}