header {
    background: var(--primary);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 100;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Poppins', sans-serif;
    font-weight: 700;
    line-height: 1.2;
    color: var(--dark);
}

a {
    text-decoration: none;
    color: var(--primary);
    transition: var(--transition);
}

a:hover {
    color: var(--primary-dark);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 8px;
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    box-shadow: var(--shadow-sm);
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

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

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

.btn-secondary {
    background: var(--secondary);
    color: var(--dark);
}

.btn-secondary:hover {
    background: #e0a520;
    color: var(--dark);
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--primary);
    color: var(--primary);
}

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

.section {
    padding: 100px 0;
    position: relative;
}

.section-title {
    text-align: center;
    margin-bottom: 60px;
    position: relative;
}

.section-title h2 {
    font-size: 2.5rem;
    display: inline-block;
    margin-bottom: 15px;
    position: relative;
}

.section-title h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--secondary);
    border-radius: 2px;
}

.section-title p {
    color: var(--gray);
    font-size: 1.1rem;
    max-width: 700px;
    margin: 20px auto 0;
}

.card {
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    height: 100%;
    border: none;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

.card-img {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.card-body {
    padding: 25px;
}

.card-title {
    font-size: 1.25rem;
    margin-bottom: 15px;
}

.card-text {
    color: var(--gray);
    margin-bottom: 20px;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, rgba(44, 95, 140, 0.9) 0%, rgba(29, 70, 105, 0.95) 100%), url('image/indexBackground.jpg') center/cover no-repeat;
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding: 120px 0 80px;
    color: white;
}

.hero-content {
    max-width: 800px;
    text-align: center;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
    z-index: 2;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    color: white;
    line-height: 1.2;
}

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

.hero-btns {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.stats {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    padding: 30px;
    margin-top: 50px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 30px;
}

.stat-item {
    text-align: center;
    padding: 0 20px;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 5px;
    line-height: 1;
}

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

/* About Section */
.about {
    background: white;
}

.about-content {
    display: flex;
    align-items: center;
    gap: 50px;
}

.about-img {
    flex: 1;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.about-img img {
    width: 100%;
    height: auto;
    transition: transform 0.5s ease;
}

.about-img:hover img {
    transform: scale(1.05);
}

.about-text {
    flex: 1;
}

.about-text h2 {
    margin-bottom: 20px;
}

.about-text p {
    margin-bottom: 15px;
    color: var(--gray);
}

/* Courses Section */
.courses {
    background: #f5f7fa;
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
}

.course-card .card-img {
    position: relative;
}

.course-card .badge {
    position: absolute;
    top: 15px;
    right: 15px;
    background: var(--secondary);
    color: var(--dark);
    font-weight: 600;
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
}

.course-card .card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 25px;
    background: #f8fafc;
    border-top: 1px solid #e2e8f0;
}

.course-card .price {
    font-weight: 700;
    color: var(--primary);
    font-size: 1.25rem;
}

/* Features Section */
.features {
    background: white;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    text-align: center;
    padding: 40px 30px;
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: rgba(44, 95, 140, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 25px;
    font-size: 2rem;
    color: var(--primary);
}

.feature-card h3 {
    margin-bottom: 15px;
}

.feature-card p {
    color: var(--gray);
}

/* Instructors Section */
.instructors {
    background: linear-gradient(to bottom, #f5f7fa 50%, white 50%);
}

.instructors-content {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    padding: 60px;
    position: relative;
    overflow: hidden;
}

.instructor-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

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

.instructor-img {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid var(--primary);
    margin: 0 auto 20px;
    transition: var(--transition);
}

.instructor-card:hover .instructor-img {
    transform: scale(1.05);
}

.instructor-social {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 20px;
}

.instructor-social a {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: #f1f5f9;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
    transition: var(--transition);
}

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

/* Testimonials Section */
.testimonials {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    position: relative;
}

.testimonial-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.testimonial-card {
    background: rgba(255, 255, 255, 0.08);
    border-radius: var(--border-radius);
    padding: 30px;
    position: relative;
}

.testimonial-card::before {
    content: "“";
    position: absolute;
    top: 20px;
    left: 25px;
    font-size: 5rem;
    font-family: Georgia, serif;
    color: rgba(255, 255, 255, 0.15);
    line-height: 1;
}

.testimonial-text {
    position: relative;
    z-index: 2;
    font-style: italic;
    margin-bottom: 25px;
}

.testimonial-author {
    display: flex;
    align-items: center;
    gap: 15px;
}

.testimonial-author img {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    object-fit: cover;
}

.author-info h4 {
    color: white;
    margin-bottom: 5px;
}

.author-info p {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.9rem;
}

/* CTA Section */
.cta {
    background: linear-gradient(135deg, var(--secondary) 0%, #e0a520 100%);
    color: var(--dark);
    text-align: center;
    padding: 80px 0;
}

.cta h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    color: var(--dark);
}

.cta p {
    max-width: 700px;
    margin: 0 auto 40px;
    font-size: 1.1rem;
}