/* Hero Section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 2rem;
}

.hero h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

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

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

.btn {
    padding: 0.8rem 2rem;
    border: none;
    border-radius: 5px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-primary {
    background: white;
    color: #667eea;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: #667eea;
}

/* Main Content */
.main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

.section-title {
    text-align: center;
    font-size: 2rem;
    font-weight: 600;
    color: #2c3e50;
    margin-bottom: 3rem;
}

/* Course Categories */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.category-card {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
    border-left: 4px solid #3498db;
}

.category-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
}

.category-icon {
    width: 60px;
    height: 60px;
    background: #e8f4fd;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.category-icon i {
    font-size: 1.5rem;
    color: #3498db;
}

.category-card h3 {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #2c3e50;
}

.category-card p {
    color: #5a6c7d;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.units-count {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 1.5rem;
    padding-top: 1rem;
    border-top: 1px solid #ecf0f1;
}

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

.unit-number {
    font-size: 1.5rem;
    font-weight: 700;
    color: #3498db;
}

.unit-label {
    font-size: 0.9rem;
    color: #5a6c7d;
}

/* Featured Units */
.featured-units {
    margin-top: 4rem;
}

.units-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.unit-card {
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.unit-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

.unit-header {
    padding: 1.5rem;
    background: #f8f9fa;
}

.unit-code {
    font-size: 0.9rem;
    color: #3498db;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.unit-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: #2c3e50;
    margin-bottom: 0.5rem;
}

.unit-credits {
    font-size: 0.8rem;
    color: #5a6c7d;
}

.unit-body {
    padding: 1.5rem;
}

.unit-description {
    color: #5a6c7d;
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

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

.difficulty {
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.difficulty.beginner {
    background: #d4edda;
    color: #155724;
}

.difficulty.intermediate {
    background: #fff3cd;
    color: #856404;
}

.difficulty.advanced {
    background: #f8d7da;
    color: #721c24;
}

.duration {
    font-size: 0.9rem;
    color: #5a6c7d;
}

.unit-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    flex: 1;
    text-align: center;
}

.btn-outline {
    background: transparent;
    border: 1px solid #3498db;
    color: #3498db;
}

.btn-outline:hover {
    background: #3498db;
    color: white;
}

.btn-solid {
    background: #3498db;
    color: white;
    border: 1px solid #3498db;
}

.btn-solid:hover {
    background: #2980b9;
    border-color: #2980b9;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }

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

    .hero p {
        font-size: 1rem;
    }

    .cta-buttons {
        flex-direction: column;
        align-items: center;
    }

    .main-content {
        padding: 2rem 1rem;
    }

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

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