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

:root {
    --primary-color: #0052CC;
    --secondary-color: #172B4D;
    --accent-color: #FF6B35;
    --success-color: #36B37E;
    --light-bg: #F5F5F5;
    --white: #FFFFFF;
    --text-dark: #172B4D;
    --text-light: #626F86;
    --border-color: #DFE1E6;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.15);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--white);
}

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

/* ========== Navigation ========== */
.navbar {
    background-color: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 40px;
}

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

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

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background-color: var(--primary-color);
    margin: 5px 0;
    transition: 0.3s;
}

/* ========== Hero Section ========== */
.hero {
    position: relative;
    width: 100%;
    min-height: 600px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-size: cover;
    background-position: center;
    color: var(--white);
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.4);
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    padding: 40px 20px;
    max-width: 800px;
}

.hero-content h1 {
    font-size: 48px;
    margin-bottom: 20px;
    line-height: 1.2;
}

.hero-content p {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.95;
}

.cta-buttons {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
}

.hero-image {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
}

.hero-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* ========== Buttons ========== */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 16px;
}

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

.btn-primary:hover {
    background-color: #E55A2B;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

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

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

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

.button-group {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.button-group .btn {
    flex: 1;
    min-width: 150px;
    text-align: center;
}

/* ========== Promotion Banner ========== */
.promo-banner {
    background: linear-gradient(135deg, var(--accent-color) 0%, #FF8C56 100%);
    color: var(--white);
    padding: 40px 20px;
    text-align: center;
}

.promo-banner h2 {
    font-size: 32px;
    margin-bottom: 10px;
}

.promo-banner p {
    font-size: 18px;
    margin-bottom: 5px;
}

.highlight {
    font-weight: bold;
    font-size: 22px;
}

.promo-subtext {
    font-size: 14px;
    opacity: 0.9;
}

/* ========== Courses Section ========== */
.courses {
    padding: 80px 20px;
    background-color: var(--light-bg);
}

.section-title {
    font-size: 40px;
    text-align: center;
    margin-bottom: 50px;
    color: var(--text-dark);
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.course-card {
    background-color: var(--white);
    border-radius: 10px;
    padding: 30px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    position: relative;
}

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

.course-card.featured {
    border: 2px solid var(--accent-color);
    transform: scale(1.05);
}

.badge {
    position: absolute;
    top: 20px;
    right: 20px;
    background-color: var(--success-color);
    color: var(--white);
    padding: 8px 15px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: bold;
}

.course-icon {
    font-size: 50px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.course-card h3 {
    font-size: 22px;
    margin-bottom: 15px;
    color: var(--text-dark);
}

.course-description {
    color: var(--text-light);
    margin-bottom: 20px;
    font-size: 14px;
}

.course-details {
    display: flex;
    gap: 30px;
    margin-bottom: 20px;
    padding: 15px 0;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

.detail {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    color: var(--text-light);
}

.detail i {
    color: var(--primary-color);
}

.course-price {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
    font-size: 18px;
}

.original-price {
    text-decoration: line-through;
    color: var(--text-light);
}

.promo-price {
    font-weight: bold;
    font-size: 24px;
    color: var(--accent-color);
}

/* ========== Format Section ========== */
.format {
    padding: 80px 20px;
    background-color: var(--white);
}

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

.format-card {
    background-color: var(--light-bg);
    border-radius: 10px;
    padding: 40px 30px;
    text-align: center;
    transition: all 0.3s ease;
    border-left: 5px solid var(--primary-color);
}

.format-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.format-icon {
    font-size: 60px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.format-card h3 {
    font-size: 24px;
    margin-bottom: 25px;
    color: var(--text-dark);
}

.feature-list {
    list-style: none;
    margin-bottom: 20px;
    text-align: left;
}

.feature-list li {
    padding: 10px 0;
    color: var(--text-light);
    display: flex;
    align-items: center;
    gap: 10px;
}

.feature-list i {
    color: var(--success-color);
    font-weight: bold;
}

.format-highlight {
    font-weight: 600;
    color: var(--primary-color);
    margin-top: 20px;
}

/* ========== Why Us Section ========== */
.why-us {
    padding: 80px 20px;
    background: linear-gradient(135deg, var(--secondary-color) 0%, var(--primary-color) 100%);
    color: var(--white);
}

.why-us .section-title {
    color: var(--white);
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.benefit-item {
    text-align: center;
}

.benefit-icon {
    font-size: 50px;
    color: var(--accent-color);
    margin-bottom: 15px;
}

.benefit-item h4 {
    font-size: 18px;
    margin-bottom: 10px;
}

.benefit-item p {
    font-size: 14px;
    opacity: 0.9;
}

/* ========== Contact Section ========== */
.contact {
    padding: 80px 20px;
    background-color: var(--light-bg);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    margin-top: 50px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.info-item {
    display: flex;
    gap: 20px;
}

.info-item i {
    font-size: 30px;
    color: var(--primary-color);
    min-width: 40px;
}

.info-item h4 {
    margin-bottom: 5px;
    color: var(--text-dark);
}

.info-item p {
    color: var(--text-light);
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.contact-form input,
.contact-form select,
.contact-form textarea {
    padding: 12px 15px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-family: inherit;
    font-size: 14px;
    transition: border-color 0.3s ease;
}

.contact-form input:focus,
.contact-form select:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 82, 204, 0.1);
}

/* ========== Footer ========== */
.footer {
    background-color: var(--secondary-color);
    color: var(--white);
    padding: 50px 20px 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 30px;
}

.footer-section h4 {
    margin-bottom: 15px;
    font-size: 18px;
}

.footer-section p,
.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    font-size: 14px;
    text-decoration: none;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 10px;
}

.footer-section a:hover {
    color: var(--accent-color);
}

.social-links {
    display: flex;
    gap: 15px;
}

.social-links a {
    font-size: 20px;
    transition: all 0.3s ease;
}

.social-links a:hover {
    transform: translateY(-3px);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.2);
    padding-top: 20px;
    text-align: center;
    color: rgba(255, 255, 255, 0.6);
    font-size: 13px;
}

.footer-bottom a {
    color: var(--accent-color);
    text-decoration: none;
}

/* ========== Trust Section ========== */
.trust {
    padding: 80px 20px;
    background-color: var(--white);
}

.trust-subtitle {
    text-align: center;
    font-size: 18px;
    color: var(--text-light);
    margin-bottom: 50px;
}

.trust-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.trust-category {
    background: linear-gradient(135deg, var(--light-bg) 0%, #FFFFFF 100%);
    padding: 30px;
    border-radius: 10px;
    border-left: 5px solid var(--primary-color);
    text-align: center;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

.trust-category:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-left-color: var(--accent-color);
}

.trust-category h4 {
    font-size: 20px;
    margin-bottom: 10px;
    color: var(--text-dark);
}

.trust-category p {
    font-size: 14px;
    color: var(--text-light);
}

.trust-note {
    text-align: center;
    font-size: 14px;
    color: var(--text-light);
    font-style: italic;
    margin-top: 30px;
    padding-top: 30px;
    border-top: 1px solid var(--border-color);
}

/* ========== Responsive Design ========== */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        gap: 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-menu li {
        padding: 20px 0;
        border-bottom: 1px solid var(--border-color);
    }

    .hero {
        flex-direction: column;
        padding: 40px 20px;
        text-align: center;
    }

    .hero-content {
        padding-right: 0;
        padding-bottom: 40px;
    }

    .hero-content h1 {
        font-size: 32px;
    }

    .hero-image {
        font-size: 100px;
    }

    .cta-buttons {
        justify-content: center;
    }

    .section-title {
        font-size: 28px;
        margin-bottom: 30px;
    }

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

    .course-card.featured {
        transform: scale(1);
    }

    .contact-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .promo-banner h2 {
        font-size: 24px;
    }

    .hero-content p,
    .promo-banner p {
        font-size: 16px;
    }
}

@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 24px;
    }

    .section-title {
        font-size: 22px;
    }

    .nav-menu {
        gap: 0;
    }

    .cta-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        text-align: center;
    }

    .hero-image {
        font-size: 60px;
    }

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

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

    .course-details {
        flex-direction: column;
        gap: 10px;
    }

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

    .trust-category {
        padding: 20px;
    }
}