:root {
    --primary-color: #667EEA;
    --secondary-color: #764BA2;
    --text-dark: #1a202c;
    --text-light: #718096;
    --bg-light: #f7fafc;
    --border-color: #e2e8f0;
    --success-color: #48bb78;
    --warning-color: #ed8936;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--text-dark);
    line-height: 1.6;
}

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

.navbar {
    background: white;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-dark);
}

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

.nav-links a {
    color: var(--text-dark);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

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

.btn-login {
    background: transparent;
    border: 2px solid var(--border-color);
    padding: 0.5rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-login:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-primary, .btn-secondary-large, .btn-primary-large {
    padding: 0.75rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.4);
}

.btn-primary-large {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    font-size: 1.1rem;
    padding: 1rem 2.5rem;
}

.btn-secondary-large {
    background: white;
    border: 2px solid var(--border-color);
    color: var(--text-dark);
    font-size: 1.1rem;
    padding: 1rem 2.5rem;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, #667eea10 0%, #764ba210 100%);
    display: flex;
    align-items: center;
    min-height: 600px;
}

.hero-content {
    flex: 1;
    padding: 0 20px;
    max-width: 600px;
    margin: 0 auto;
}

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

.gradient-text {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.hero-actions {
    display: flex;
    gap: 1rem;
    margin-bottom: 3rem;
}

.hero-stats {
    display: flex;
    gap: 3rem;
}

.stat {
    display: flex;
    flex-direction: column;
}

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

.stat-label {
    color: var(--text-light);
    font-size: 0.9rem;
}

.hero-demo {
    flex: 1;
    padding: 0 20px;
    display: flex;
    justify-content: center;
}

.demo-window {
    background: white;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.15);
    overflow: hidden;
    width: 100%;
    max-width: 500px;
}

.demo-header {
    padding: 12px 16px;
    background: var(--bg-light);
    display: flex;
    gap: 8px;
}

.demo-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: #ddd;
}

.demo-dot:first-child { background: #ff5f56; }
.demo-dot:nth-child(2) { background: #ffbd2e; }
.demo-dot:nth-child(3) { background: #27c93f; }

#heroVideo {
    width: 100%;
    display: block;
}

.features {
    padding: 5rem 0;
    background: white;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 3rem;
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    font-size: 1.1rem;
    margin-top: -2rem;
    margin-bottom: 3rem;
}

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

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.feature-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

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

.pricing {
    padding: 5rem 0;
    background: var(--bg-light);
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.pricing-card {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    position: relative;
    border: 2px solid var(--border-color);
    transition: all 0.3s;
}

.pricing-card.featured {
    border-color: var(--primary-color);
    transform: scale(1.05);
    box-shadow: 0 20px 40px rgba(102, 126, 234, 0.2);
}

.badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 4px 16px;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
}

.pricing-header {
    text-align: center;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
}

.pricing-header h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.price {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 4px;
}

.currency {
    font-size: 1.5rem;
    color: var(--text-light);
}

.amount {
    font-size: 3rem;
    font-weight: 800;
    color: var(--text-dark);
}

.period {
    font-size: 1.25rem;
    color: var(--text-light);
}

.price-note {
    color: var(--text-light);
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

.pricing-features {
    list-style: none;
    padding: 2rem 0;
}

.pricing-features li {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 0.75rem 0;
    color: var(--text-dark);
}

.pricing-features li svg {
    color: var(--success-color);
    flex-shrink: 0;
}

.btn-pricing {
    width: 100%;
    padding: 1rem;
    border-radius: 8px;
    border: 2px solid var(--primary-color);
    background: white;
    color: var(--primary-color);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s;
}

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

.btn-featured {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
}

.btn-featured:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.4);
}

.demo-section {
    padding: 5rem 0;
    background: white;
}

.demo-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    margin-top: 3rem;
}

.demo-input {
    padding: 2rem;
    background: var(--bg-light);
    border-radius: 12px;
}

.demo-input h3 {
    margin-bottom: 1.5rem;
}

.input-field, .select-field {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    margin-bottom: 1rem;
    transition: border-color 0.3s;
}

.input-field:focus, .select-field:focus {
    outline: none;
    border-color: var(--primary-color);
}

.btn-generate {
    width: 100%;
    padding: 1rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-generate:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.4);
}

.demo-output {
    background: var(--bg-light);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 400px;
}

.placeholder {
    text-align: center;
    color: var(--text-light);
}

.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
}

.modal-content {
    background-color: white;
    margin: 10% auto;
    padding: 2rem;
    border-radius: 12px;
    width: 90%;
    max-width: 400px;
}

.close {
    color: var(--text-light);
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
}

.close:hover {
    color: var(--text-dark);
}

.modal h2 {
    margin-bottom: 1.5rem;
}

.modal form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.btn-primary-full {
    width: 100%;
    padding: 0.75rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.modal-footer {
    text-align: center;
    margin-top: 1.5rem;
    color: var(--text-light);
}

.modal-footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

.footer {
    background: var(--text-dark);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
}

.footer-section a {
    display: block;
    color: #cbd5e0;
    text-decoration: none;
    padding: 0.25rem 0;
    transition: color 0.3s;
}

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

.social-links {
    display: flex;
    gap: 1rem;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #4a5568;
    color: #cbd5e0;
}

.courses-section {
    padding: 5rem 0;
    background: white;
}

.course-filters {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 0.5rem 1.5rem;
    border: 2px solid var(--border-color);
    background: white;
    border-radius: 20px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
}

.filter-btn:hover,
.filter-btn.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-color: transparent;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.course-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: all 0.3s;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.15);
}

.course-thumbnail {
    position: relative;
    width: 100%;
    height: 200px;
    background: var(--bg-light);
}

.course-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.course-duration {
    position: absolute;
    bottom: 10px;
    right: 10px;
    background: rgba(0,0,0,0.7);
    color: white;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.875rem;
}

.course-badge {
    position: absolute;
    top: 10px;
    left: 10px;
    background: var(--warning-color);
    color: white;
    padding: 4px 12px;
    border-radius: 4px;
    font-size: 0.875rem;
    font-weight: 600;
}

.course-info {
    padding: 1.5rem;
}

.course-info h3 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
    line-height: 1.4;
}

.course-grade {
    color: var(--primary-color);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.course-description {
    color: var(--text-light);
    font-size: 0.875rem;
    line-height: 1.5;
    margin-bottom: 1rem;
}

.course-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

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

.btn-buy {
    padding: 0.5rem 1.5rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-buy:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.courses-cta {
    text-align: center;
    padding: 3rem;
    background: var(--bg-light);
    border-radius: 12px;
}

.courses-cta p {
    font-size: 1.25rem;
    color: var(--text-dark);
    margin-bottom: 1.5rem;
}

.video-library {
    padding: 3rem 0;
}

.library-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.search-bar {
    display: flex;
    gap: 1rem;
    flex: 1;
    max-width: 500px;
}

.search-input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
}

.sort-select {
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: white;
    cursor: pointer;
}

@media (max-width: 768px) {
    .hero {
        flex-direction: column;
        padding: 2rem 0;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-actions {
        flex-direction: column;
    }
    
    .hero-stats {
        flex-wrap: wrap;
        gap: 1.5rem;
    }
    
    .demo-container {
        grid-template-columns: 1fr;
    }
    
    .pricing-grid {
        grid-template-columns: 1fr;
    }
    
    .pricing-card.featured {
        transform: none;
    }
    
    .nav-links {
        display: none;
    }
}