:root {
    --primary: #d32f2f;
    --primary-light: #ff6659;
    --primary-dark: #9a0007;
    --secondary: #002e5b;
    --secondary-light: #305889;
    --accent: #ffb300;
    --white: #ffffff;
    --black: #1a1a1a;
    --gray-100: #f8f9fa;
    --gray-200: #e9ecef;
    --gray-300: #dee2e6;
    --gray-600: #6c757d;
    --gray-800: #343a40;
    --font-main: 'Roboto', sans-serif;
    --font-heading: 'Montserrat', sans-serif;
    --shadow-sm: 0 .125rem .25rem rgba(0,0,0,.075);
    --shadow-md: 0 .5rem 1rem rgba(0,0,0,.15);
    --shadow-lg: 0 1rem 3rem rgba(0,0,0,.175);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    margin: 0;
    font-family: var(--font-main);
    font-size: 16px;
    color: var(--black);
    background-color: var(--white);
    line-height: 1.6;
    overflow-x: hidden;
}
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    margin-bottom: 1rem;
    line-height: 1.2;
    font-weight: 700;
}
p { margin-bottom: 1rem; }
a { text-decoration: none; color: inherit; transition: var(--transition); }
ul { list-style: none; padding: 0; margin: 0; }
img { max-width: 100%; height: auto; }
button, input, select, textarea { font-family: inherit; }
.container {
    width: 100%;
    padding-right: 15px;
    padding-left: 15px;
    margin-right: auto;
    margin-left: auto;
    max-width: 1200px;
}
.text-center { text-align: center; }
.py-100 { padding-top: 100px; padding-bottom: 100px; }
.mb-50 { margin-bottom: 50px; }
.btn-primary {
    background: var(--primary);
    color: white;
    padding: 12px 30px;
    border-radius: 50px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    display: inline-block;
}
.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}
.topbar {
    background: var(--secondary);
    color: white;
    padding: 10px 0;
    font-size: 13px;
    border-bottom: 1px solid rgba(31, 6, 6, 0.1);
}
.topbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.topbar-info span { margin-right: 20px; }
.topbar-social a { margin-left: 15px; opacity: 0.8; }
.topbar-social a:hover { opacity: 1; }
header {
    background: white;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
    padding: 15px 0;
}
header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.logo { display: flex; align-items: center; gap: 10px; }
.logo-icon {
    width: 45px;
    height: 45px;
    border-radius: 10px; /* Độ bo tròn của góc, bạn có thể tăng/giảm số này (vd: 12px, 15px) */
    object-fit: contain; /* Giúp logo hiển thị đầy đủ không bị cắt xén */
    background-color: white; /* Thêm nền trắng để logo nổi bật hơn nếu cần */
    border: 1px solid var(--gray-200); /* Thêm viền mỏng cho sắc nét (tùy chọn) */
}
.logo-text h2 {
    margin: 0;
    font-size: 18px;
    color: var(--secondary);
    letter-spacing: 1px;
}
.logo-text span {
    font-size: 10px;
    text-transform: uppercase;
    color: var(--gray-600);
    display: block;
}
.nav-menu ul { display: flex; gap: 5px; }
.nav-menu ul li { position: relative; }
.nav-menu ul li a {
    padding: 10px 15px;
    font-weight: 600;
    font-size: 14px;
    color: var(--secondary);
    text-transform: uppercase;
}
.nav-menu ul li a:hover { color: var(--primary); }
.dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    background: white;
    min-width: 250px;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    border-top: 4px solid var(--primary);
    padding: 15px 0;
}
.nav-menu ul li:hover .dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.dropdown li { width: 100%; }
.dropdown li a {
    display: block;
    padding: 10px 25px;
    text-transform: none;
    border-bottom: 1px solid var(--gray-200);
}
.dropdown li a:hover {
    background: var(--gray-100);
    padding-left: 30px;
    color: var(--primary);
}
.hero {
    height: 700px;
    background: var(--gray-100);
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
}
.hero-shape {
    position: absolute;
    top: 0;
    right: 0;
    width: 50%;
    height: 100%;
    background: var(--secondary);
    clip-path: polygon(25% 0%, 100% 0%, 100% 100%, 0% 100%);
    z-index: 1;
}
.hero-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.hero-content {
    position: relative;
    z-index: 2;
    width: 55%;
}
.hero-content h1 {
    font-size: 56px;
    color: var(--secondary);
    margin-bottom: 20px;
}
.hero-content h1 span { color: var(--primary); }
.hero-content p {
    font-size: 18px;
    color: var(--gray-800);
    margin-bottom: 30px;
    max-width: 500px;
}
.hero-image-placeholder {
    position: relative;
    z-index: 2;
    width: 45%;
    height: 500px;
    background: #ddd;
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    box-shadow: var(--shadow-lg);
    border: 5px solid white;
}
.stats {
    background: white;
    margin-top: -50px;
    position: relative;
    z-index: 3;
}
.stats-wrapper {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    background: white;
    box-shadow: var(--shadow-md);
    border-radius: 10px;
    padding: 40px 0;
}
.stat-item {
    text-align: center;
    border-right: 1px solid var(--gray-200);
}
.stat-item:last-child { border-right: none; }
.stat-number {
    font-size: 42px;
    font-weight: 800;
    color: var(--primary);
    display: block;
}
.stat-label {
    font-weight: 600;
    color: var(--secondary);
    text-transform: uppercase;
    font-size: 14px;
}
.section-title h2 {
    font-size: 36px;
    color: var(--secondary);
    margin-bottom: 15px;
}
.section-title .divider {
    width: 80px;
    height: 4px;
    background: var(--primary);
    margin: 0 auto 30px;
}
.tabs-nav {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 50px;
}
.tab-link {
    padding: 15px 35px;
    background: var(--gray-200);
    border: none;
    border-radius: 5px;
    font-weight: 700;
    cursor: pointer;
    color: var(--secondary);
}
.tab-link.active {
    background: var(--primary);
    color: white;
}
.course-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}
.course-card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-200);
    position: relative;
    transition: var(--transition);
}
.course-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}
.course-thumb {
    height: 250px;
    background: #eee;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    position: relative;
}
.course-badge {
    position: absolute;
    top: 15px;
    left: 15px;
    background: var(--accent);
    color: var(--black);
    padding: 5px 15px;
    font-size: 12px;
    font-weight: 700;
    border-radius: 4px;
}
.course-body { padding: 25px; }
.course-body h3 {
    font-size: 20px;
    color: var(--secondary);
    height: 50px;
    overflow: hidden;
}
.course-info-list {
    display: flex;
    justify-content: space-between;
    margin-top: 20px;
    padding-top: 15px;
    border-top: 1px solid var(--gray-200);
    font-size: 14px;
    color: var(--gray-600);
}
.why-us { background: var(--gray-100); }
.feature-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
}
.feature-item {
    display: flex;
    gap: 20px;
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: var(--shadow-sm);
}
.feature-icon {
    width: 60px;
    height: 60px;
    background: var(--primary);
    border-radius: 10px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 24px;
}
.feature-text h4 { margin: 0 0 10px; color: var(--secondary); }
.testimonial-card {
    background: white;
    padding: 40px;
    border-radius: 20px;
    box-shadow: var(--shadow-md);
    text-align: center;
    position: relative;
    margin: 20px;
}
.client-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: #ddd;
    margin: 0 auto 20px;
    border: 4px solid var(--gray-200);
    display: flex;
    align-items: center;
    justify-content: center;
}
.client-info h5 { margin: 0; color: var(--primary); }
.client-info span { font-size: 13px; color: var(--gray-600); }
.testimonials-section { background: var(--gray-100); }
.testimonial-row { display: flex; overflow: hidden; }
.accordion-item { border-bottom: 1px solid var(--gray-300); }
.accordion-header {
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-weight: 700;
    color: var(--secondary);
}
.accordion-content {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: var(--transition);
    background: var(--gray-100);
}
.accordion-item.active .accordion-content {
    padding: 20px;
    max-height: 200px;
}
.accordion-header::after {
    content: '+';
    font-size: 20px;
}
.accordion-item.active .accordion-header::after { content: '-'; }
.cta-section {
    background: var(--secondary);
    color: white;
}
.cta-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}
.reg-form {
    background: white;
    padding: 40px;
    border-radius: 10px;
    color: var(--black);
}
.form-group { margin-bottom: 20px; }
.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
}
.form-control {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--gray-300);
    border-radius: 5px;
}
.form-submit-btn {
    width: 100%;
    border-radius: 5px;
    height: 50px;
}
footer {
    background: #0b1d33;
    color: #a5b4c4;
    padding: 80px 0 20px;
}
.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
}
.footer-title {
    color: white;
    font-size: 18px;
    margin-bottom: 25px;
    position: relative;
    padding-bottom: 10px;
}
.footer-title::after {
    content: '';
    width: 40px;
    height: 2px;
    background: var(--primary);
    position: absolute;
    bottom: 0;
    left: 0;
}
.footer-links li { margin-bottom: 12px; }
.footer-links a:hover {
    color: white;
    padding-left: 5px;
}
.copyright {
    border-top: 1px solid rgba(255,255,255,0.05);
    margin-top: 50px;
    padding-top: 25px;
    text-align: center;
    font-size: 14px;
}
.floating-action {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 1000;
}
.fab-item {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--primary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    margin-top: 15px;
    cursor: pointer;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}
.fab-item:hover { transform: scale(1.1); }
.fab-zalo { background: #0084FF; }
[data-reveal] {
    opacity: 0;
    transform: translateY(30px);
    transition: 0.8s ease-out;
}
[data-reveal].revealed {
    opacity: 1;
    transform: translateY(0);
}
.faq-wrap {
    max-width: 800px;
    margin: 0 auto;
}
@media (max-width: 992px) {
    .hero-content { width: 100%; text-align: center; }
    .hero-shape, .hero-image-placeholder { display: none; }
    .stats-wrapper { grid-template-columns: repeat(2, 1fr); }
    .course-grid, .footer-grid { grid-template-columns: repeat(2, 1fr); }
    .feature-grid, .cta-grid { grid-template-columns: 1fr; }
    .testimonial-row { flex-direction: column; }
}
@media (max-width: 576px) {
    .stats-wrapper, .course-grid, .footer-grid { grid-template-columns: 1fr; }
    .topbar { display: none; }
    .hero-content h1 { font-size: 36px; }
    .tabs-nav { flex-direction: column; }
}