:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --text-color: #1f2937;
    --light-text: #6b7280;
    --background-color: #ffffff;
    --section-bg: #f3f4f6;
}

* {
    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: var(--text-color);
}

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

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 100px 0;
    text-align: center;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    font-weight: 800;
}

.hero h2 {
    font-size: 2rem;
    margin-bottom: 20px;
    font-weight: 600;
}

.hero .subtitle {
    font-size: 1.25rem;
    margin-bottom: 40px;
    opacity: 0.9;
}

/* CTA Button */
.cta-button {
    display: inline-block;
    padding: 15px 40px;
    background-color: white;
    color: var(--primary-color);
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1.1rem;
    transition: transform 0.2s ease;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

/* Features Section */
.features {
    padding: 80px 0;
    background-color: var(--background-color);
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.feature-item {
    text-align: center;
    padding: 30px;
    border-radius: 10px;
    background-color: white;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.2s ease;
}

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

.feature-item i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.feature-item h3 {
    margin-bottom: 15px;
    font-size: 1.5rem;
}

/* Curriculum Section */
.curriculum {
    padding: 80px 0;
    background-color: var(--section-bg);
}

.curriculum h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
}

.curriculum-list {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.curriculum-item {
    background-color: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

.curriculum-item h3 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 1.3rem;
}

.curriculum-item ul {
    list-style-position: inside;
    color: var(--light-text);
}

/* Instructor Section */
.instructor {
    padding: 80px 0;
    background-color: white;
}

.instructor h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
}

.instructor-info {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 20px;
    max-width: 800px;
    margin: 0 auto;
}

.instructor-image img {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
}

.instructor-text h3 {
    font-size: 1.8rem;
    margin-bottom: 10px;
}

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

.social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 20px;
}

.social-links a {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--section-bg);
    border-radius: 50%;
    transition: all 0.3s ease;
}

.social-links a:hover {
    background-color: var(--primary-color);
    color: white;
}

/* CTA Section */
.cta {
    padding: 80px 0;
    background-color: var(--section-bg);
    text-align: center;
}

.cta h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.cta p {
    margin-bottom: 30px;
    color: var(--light-text);
    font-size: 1.2rem;
}

/* Footer */
footer {
    background-color: var(--text-color);
    color: white;
    padding: 40px 0;
}

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

.footer-social {
    margin-bottom: 20px;
}

.footer-social a {
    color: white;
    text-decoration: none;
    margin: 0 15px;
    opacity: 0.8;
    transition: opacity 0.2s ease;
}

.footer-social a:hover {
    opacity: 1;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .hero h2 {
        font-size: 1.5rem;
    }

    .instructor-info {
        flex-direction: column;
        text-align: center;
    }

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

    .curriculum-list {
        grid-template-columns: 1fr;
    }
}

/* Module Grid */
.module-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 30px;
    margin-top: 40px;
}

.module-item {
    background-color: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.2s ease;
}

.module-item:hover {
    transform: translateY(-5px);
}

.module-item h3 {
    cursor: pointer;
    position: relative;
    padding: 15px;
    background-color: var(--section-bg);
    border-radius: 8px;
    margin: -15px -15px 15px -15px;
    transition: all 0.3s ease;
}

.module-item h3:hover {
    background-color: #e5e7eb;
}

.module-item h3 i {
    margin-right: 10px;
    transition: transform 0.3s ease;
}

.module-item h3.active i {
    transform: rotate(90deg);
}

.lesson-list {
    list-style: none;
    transition: all 0.3s ease;
}

.lesson-list li {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0;
    border-bottom: 1px solid var(--section-bg);
    color: var(--text-color);
}

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

.lesson-title {
    flex: 1;
    padding-right: 20px;
}

.duration {
    color: var(--light-text);
    font-family: monospace;
    font-size: 0.9rem;
    background-color: var(--section-bg);
    padding: 4px 8px;
    border-radius: 4px;
    white-space: nowrap;
}

@media (max-width: 768px) {
    .lesson-list li {
        flex-direction: column;
        align-items: flex-start;
        gap: 5px;
    }

    .lesson-title {
        padding-right: 0;
    }

    .duration {
        align-self: flex-start;
    }

    .curriculum-list {
        grid-template-columns: 1fr;
    }
}