/* =============================================
   LANDING PAGE — KHÓA HỌC NGHIÊN CỨU MARKETING
   Phong cách: Sáng, hiện đại, premium
   Font: Be Vietnam Pro (Google Fonts - hỗ trợ tiếng Việt)
   ============================================= */

/* --- CSS Custom Properties (Design Tokens) --- */
:root {
  /* Bảng màu chính */
  --primary: #2563EB;
  --primary-dark: #1D4ED8;
  --primary-light: #DBEAFE;
  --primary-50: #EFF6FF;
  --secondary: #7C3AED;
  --secondary-light: #EDE9FE;
  --accent: #F59E0B;
  --accent-dark: #D97706;
  --accent-light: #FEF3C7;

  /* Nền và text */
  --bg-main: #FAFBFF;
  --bg-white: #FFFFFF;
  --bg-light: #F1F5F9;
  --text-primary: #1E293B;
  --text-secondary: #475569;
  --text-light: #94A3B8;
  --text-white: #FFFFFF;

  /* Viền và shadow */
  --border: #E2E8F0;
  --border-light: #F1F5F9;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
  --shadow-md: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
  --shadow-lg: 0 20px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.04);
  --shadow-xl: 0 25px 50px -12px rgba(0,0,0,0.15);
  --shadow-glow: 0 0 40px rgba(37,99,235,0.15);

  /* Bo góc */
  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Hiệu ứng chuyển động */
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --transition: all 0.3s var(--ease);
  --transition-slow: all 0.5s var(--ease);

  /* Kích thước */
  --max-width: 1200px;
  --nav-height: 72px;
}

/* --- Reset & Base --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: 'Be Vietnam Pro', system-ui, -apple-system, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-primary);
  background: var(--bg-main);
  overflow-x: hidden;
}

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

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

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

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  line-height: 1.3;
  font-weight: 700;
  color: var(--text-primary);
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.75rem, 4vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.5rem); }

p {
  color: var(--text-secondary);
  line-height: 1.8;
}

/* --- Layout --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 100px 0;
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 60px;
}

.section-header h2 {
  margin-bottom: 16px;
  position: relative;
}

.section-header p {
  font-size: 1.1rem;
}

/* Thanh trang trí dưới tiêu đề section */
.section-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--primary-50);
  color: var(--primary);
  padding: 6px 16px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

/* --- Nút bấm --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 32px;
  border: none;
  border-radius: var(--radius-full);
  font-family: inherit;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: var(--text-white);
  box-shadow: 0 4px 15px rgba(37,99,235,0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(37,99,235,0.4);
  color: var(--text-white);
}

.btn-primary:active {
  transform: translateY(0);
}

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

.btn-secondary:hover {
  background: var(--primary-50);
  color: var(--primary);
}

.btn-accent {
  background: linear-gradient(135deg, var(--accent), var(--accent-dark));
  color: var(--text-white);
  box-shadow: 0 4px 15px rgba(245,158,11,0.3);
}

.btn-accent:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(245,158,11,0.4);
  color: var(--text-white);
}

.btn-lg {
  padding: 18px 40px;
  font-size: 1.1rem;
}

/* Hiệu ứng shimmer trên nút */
.btn-primary::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  animation: shimmer 3s infinite;
}

@keyframes shimmer {
  0% { left: -100%; }
  100% { left: 100%; }
}

/* =============================================
   NAVIGATION
   ============================================= */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(226,232,240,0.5);
  z-index: 1000;
  transition: var(--transition);
}

.navbar.scrolled {
  box-shadow: var(--shadow);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text-primary);
}

.nav-logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.1rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: var(--transition);
  border-radius: 2px;
}

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

.nav-links a:hover::after {
  width: 100%;
}

.nav-cta {
  padding: 10px 24px !important;
  font-size: 0.9rem !important;
}

/* Hamburger menu (mobile) */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  background: none;
  border: none;
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

/* =============================================
   HERO SECTION
   ============================================= */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: var(--nav-height);
  background: linear-gradient(135deg, #EFF6FF 0%, #F5F3FF 50%, #FEF3C7 100%);
}

/* Hình trang trí động nền hero */
.hero-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.hero-shape {
  position: absolute;
  border-radius: 50%;
  opacity: 0.15;
  filter: blur(60px);
}

.hero-shape-1 {
  width: 500px;
  height: 500px;
  background: var(--primary);
  top: -100px;
  right: -100px;
  animation: float 8s ease-in-out infinite;
}

.hero-shape-2 {
  width: 400px;
  height: 400px;
  background: var(--secondary);
  bottom: -50px;
  left: -50px;
  animation: float 10s ease-in-out infinite reverse;
}

.hero-shape-3 {
  width: 300px;
  height: 300px;
  background: var(--accent);
  top: 40%;
  left: 60%;
  animation: float 12s ease-in-out infinite 2s;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(30px, -30px) scale(1.05); }
  66% { transform: translate(-20px, 20px) scale(0.95); }
}

.hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  position: relative;
  z-index: 2;
}

.hero-content {
  max-width: 600px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(37,99,235,0.1);
  color: var(--primary);
  padding: 8px 20px;
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 24px;
  border: 1px solid rgba(37,99,235,0.15);
}

.hero-badge svg {
  width: 16px;
  height: 16px;
}

.hero-title {
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}

.hero-title .highlight {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 36px;
  line-height: 1.8;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-stats {
  display: flex;
  gap: 40px;
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}

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

.hero-stat-number {
  font-size: 2rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
}

.hero-stat-label {
  font-size: 0.85rem;
  color: var(--text-light);
  margin-top: 4px;
}

/* Card hình ảnh hero bên phải */
.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
}

.hero-image-card {
  position: relative;
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-xl);
  max-width: 450px;
  width: 100%;
  transform: perspective(1000px) rotateY(-5deg) rotateX(3deg);
  transition: var(--transition-slow);
}

.hero-image-card:hover {
  transform: perspective(1000px) rotateY(0deg) rotateX(0deg);
}

.hero-image-card img {
  width: 100%;
  height: 500px;
  object-fit: cover;
  object-position: top center;
}

/* Thẻ nổi trên hình hero */
.hero-float-card {
  position: absolute;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(10px);
  border-radius: var(--radius);
  padding: 16px 20px;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 12px;
  animation: floatCard 4s ease-in-out infinite;
}

.hero-float-card-1 {
  bottom: 40px;
  left: -30px;
}

.hero-float-card-2 {
  top: 40px;
  right: -30px;
  animation-delay: 2s;
}

@keyframes floatCard {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.float-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  flex-shrink: 0;
}

.float-icon.blue { background: var(--primary-light); color: var(--primary); }
.float-icon.purple { background: var(--secondary-light); color: var(--secondary); }

.float-text strong {
  display: block;
  font-size: 0.9rem;
  color: var(--text-primary);
}

.float-text span {
  font-size: 0.8rem;
  color: var(--text-light);
}

/* =============================================
   ABOUT SECTION
   ============================================= */
.about {
  background: var(--bg-white);
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

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

.about-content p {
  margin-bottom: 24px;
  font-size: 1.05rem;
}

.about-features {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 32px;
}

.about-feature {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: var(--bg-main);
  border-radius: var(--radius);
  transition: var(--transition);
}

.about-feature:hover {
  background: var(--primary-50);
  transform: translateX(4px);
}

.about-feature-icon {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 0.9rem;
  flex-shrink: 0;
}

.about-feature span {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-primary);
}

/* Card thông số bên phải */
.about-visual {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.about-stat-card {
  background: var(--bg-main);
  border-radius: var(--radius-lg);
  padding: 28px;
  text-align: center;
  transition: var(--transition);
  border: 1px solid var(--border-light);
}

.about-stat-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary-light);
}

.about-stat-card:nth-child(2) {
  transform: translateY(20px);
}

.about-stat-card:nth-child(2):hover {
  transform: translateY(16px);
}

.about-stat-card:nth-child(3) {
  transform: translateY(-10px);
}

.about-stat-card:nth-child(3):hover {
  transform: translateY(-14px);
}

.about-stat-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  font-size: 1.5rem;
}

.about-stat-icon.blue { background: var(--primary-light); }
.about-stat-icon.purple { background: var(--secondary-light); }
.about-stat-icon.amber { background: var(--accent-light); }
.about-stat-icon.green { background: #D1FAE5; }

.about-stat-card h3 {
  font-size: 1.8rem;
  color: var(--primary);
  margin-bottom: 4px;
}

.about-stat-card p {
  font-size: 0.9rem;
  color: var(--text-light);
}

/* =============================================
   CURRICULUM SECTION
   ============================================= */
.curriculum {
  background: var(--bg-main);
}

.curriculum-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.curriculum-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 32px;
  border: 1px solid var(--border-light);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.curriculum-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  transform: scaleX(0);
  transform-origin: left;
  transition: var(--transition);
}

.curriculum-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.curriculum-card:hover::before {
  transform: scaleX(1);
}

.curriculum-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: white;
  border-radius: var(--radius-sm);
  font-size: 1.1rem;
  font-weight: 800;
  margin-bottom: 20px;
}

.curriculum-card h3 {
  font-size: 1.15rem;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.curriculum-card p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* =============================================
   BENEFITS SECTION
   ============================================= */
.benefits {
  background: var(--bg-white);
  position: relative;
}

.benefits-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.benefit-card {
  display: flex;
  gap: 16px;
  padding: 24px;
  background: var(--bg-main);
  border-radius: var(--radius-lg);
  transition: var(--transition);
  border: 1px solid transparent;
}

.benefit-card:hover {
  background: var(--bg-white);
  border-color: var(--primary-light);
  box-shadow: var(--shadow);
  transform: translateY(-4px);
}

.benefit-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--primary-light), var(--secondary-light));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  flex-shrink: 0;
}

.benefit-card h4 {
  font-size: 1rem;
  margin-bottom: 6px;
}

.benefit-card p {
  font-size: 0.9rem;
  color: var(--text-light);
}

/* =============================================
   INSTRUCTOR SECTION
   ============================================= */
.instructor {
  background: linear-gradient(135deg, #EFF6FF 0%, #F5F3FF 100%);
}

.instructor-card {
  display: grid;
  grid-template-columns: 350px 1fr;
  gap: 60px;
  align-items: center;
  background: var(--bg-white);
  border-radius: var(--radius-xl);
  padding: 48px;
  box-shadow: var(--shadow-lg);
  max-width: 900px;
  margin: 0 auto;
}

.instructor-image {
  border-radius: var(--radius-lg);
  overflow: hidden;
  position: relative;
}

.instructor-image img {
  width: 100%;
  height: 400px;
  object-fit: cover;
  object-position: top center;
}

.instructor-image::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  border: 3px solid rgba(37,99,235,0.1);
}

.instructor-info h3 {
  font-size: 1.6rem;
  margin-bottom: 4px;
}

.instructor-title {
  color: var(--primary);
  font-weight: 600;
  font-size: 1.05rem;
  margin-bottom: 20px;
}

.instructor-bio {
  font-size: 1.05rem;
  margin-bottom: 24px;
}

.instructor-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.instructor-tag {
  padding: 6px 16px;
  background: var(--primary-50);
  color: var(--primary);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
}

/* =============================================
   COURSE INFO SECTION
   ============================================= */
.course-info {
  background: var(--bg-white);
}

.info-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.info-card {
  text-align: center;
  padding: 36px 24px;
  background: var(--bg-main);
  border-radius: var(--radius-lg);
  transition: var(--transition);
  border: 1px solid var(--border-light);
}

.info-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
  border-color: var(--primary-light);
}

.info-icon {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-lg);
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  background: linear-gradient(135deg, var(--primary-light), var(--secondary-light));
}

.info-card h4 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-light);
  margin-bottom: 8px;
}

.info-card p {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* =============================================
   TESTIMONIALS SECTION
   ============================================= */
.testimonials {
  background: var(--bg-main);
}

.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.testimonial-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 32px;
  border: 1px solid var(--border-light);
  transition: var(--transition);
  position: relative;
}

.testimonial-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.testimonial-quote {
  font-size: 3rem;
  line-height: 1;
  color: var(--primary-light);
  margin-bottom: 16px;
  font-family: Georgia, serif;
}

.testimonial-text {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
  font-style: italic;
  line-height: 1.8;
}

.testimonial-author {
  display: flex;
  align-items: center;
  gap: 12px;
}

.testimonial-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 700;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.testimonial-name {
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.95rem;
}

.testimonial-role {
  font-size: 0.85rem;
  color: var(--text-light);
}

/* Ngôi sao đánh giá */
.testimonial-stars {
  display: flex;
  gap: 2px;
  margin-bottom: 16px;
}

.testimonial-stars svg {
  width: 18px;
  height: 18px;
  fill: var(--accent);
}

/* =============================================
   CTA SECTION (CUỐI TRANG)
   ============================================= */
.cta-section {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  padding: 100px 0;
  position: relative;
  overflow: hidden;
}

/* Hình trang trí CTA */
.cta-section::before,
.cta-section::after {
  content: '';
  position: absolute;
  border-radius: 50%;
  opacity: 0.1;
}

.cta-section::before {
  width: 400px;
  height: 400px;
  background: white;
  top: -100px;
  right: -100px;
}

.cta-section::after {
  width: 300px;
  height: 300px;
  background: white;
  bottom: -80px;
  left: -80px;
}

.cta-content {
  text-align: center;
  position: relative;
  z-index: 2;
}

.cta-content h2 {
  color: white;
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  margin-bottom: 16px;
}

.cta-content p {
  color: rgba(255,255,255,0.85);
  font-size: 1.15rem;
  max-width: 600px;
  margin: 0 auto 36px;
}

.cta-content .btn-accent {
  background: white;
  color: var(--primary);
  font-weight: 700;
  box-shadow: 0 4px 20px rgba(0,0,0,0.15);
}

.cta-content .btn-accent:hover {
  background: var(--accent-light);
  color: var(--primary-dark);
}

/* =============================================
   FOOTER
   ============================================= */
.footer {
  background: var(--text-primary);
  color: rgba(255,255,255,0.7);
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-brand h3 {
  color: white;
  font-size: 1.3rem;
  margin-bottom: 12px;
}

.footer-brand p {
  color: rgba(255,255,255,0.6);
  font-size: 0.95rem;
  line-height: 1.7;
}

.footer-links h4 {
  color: white;
  font-size: 1rem;
  margin-bottom: 16px;
}

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

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

.footer-links a {
  color: rgba(255,255,255,0.6);
  font-size: 0.95rem;
  transition: var(--transition);
}

.footer-links a:hover {
  color: white;
}

.footer-contact-item {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
  font-size: 0.95rem;
}

.footer-contact-item svg {
  width: 18px;
  height: 18px;
  color: var(--primary);
  flex-shrink: 0;
}

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 24px;
  text-align: center;
  font-size: 0.85rem;
  color: rgba(255,255,255,0.4);
}

/* =============================================
   MODAL / POPUP ĐĂNG KÝ
   ============================================= */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15,23,42,0.6);
  backdrop-filter: blur(8px);
  z-index: 10000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: var(--bg-white);
  border-radius: var(--radius-xl);
  padding: 48px;
  max-width: 500px;
  width: 100%;
  position: relative;
  transform: translateY(20px) scale(0.95);
  transition: var(--transition-slow);
  box-shadow: var(--shadow-xl);
}

.modal-overlay.active .modal {
  transform: translateY(0) scale(1);
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: none;
  background: var(--bg-light);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: var(--text-secondary);
  transition: var(--transition);
}

.modal-close:hover {
  background: #FEE2E2;
  color: #EF4444;
}

.modal h2 {
  font-size: 1.5rem;
  margin-bottom: 8px;
}

.modal > p {
  color: var(--text-secondary);
  margin-bottom: 28px;
  font-size: 0.95rem;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.form-group input {
  width: 100%;
  padding: 14px 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  font-family: inherit;
  font-size: 1rem;
  transition: var(--transition);
  background: var(--bg-main);
}

.form-group input:focus {
  outline: none;
  border-color: var(--primary);
  background: var(--bg-white);
  box-shadow: 0 0 0 4px rgba(37,99,235,0.1);
}

.form-group input::placeholder {
  color: var(--text-light);
}

/* Honeypot - ẩn khỏi người dùng thật */
.form-hp {
  position: absolute;
  left: -9999px;
  opacity: 0;
  height: 0;
  overflow: hidden;
}

.form-submit {
  width: 100%;
  margin-top: 8px;
}

/* Thông báo trạng thái */
.form-message {
  padding: 14px 16px;
  border-radius: var(--radius);
  font-size: 0.95rem;
  margin-top: 16px;
  display: none;
}

.form-message.success {
  background: #D1FAE5;
  color: #065F46;
  display: block;
}

.form-message.error {
  background: #FEE2E2;
  color: #991B1B;
  display: block;
}

/* =============================================
   SCROLL ANIMATIONS
   ============================================= */
.fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease);
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger animation cho cards */
.stagger > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s var(--ease), transform 0.5s var(--ease);
}

.stagger.visible > *:nth-child(1) { transition-delay: 0.1s; }
.stagger.visible > *:nth-child(2) { transition-delay: 0.2s; }
.stagger.visible > *:nth-child(3) { transition-delay: 0.3s; }
.stagger.visible > *:nth-child(4) { transition-delay: 0.4s; }
.stagger.visible > *:nth-child(5) { transition-delay: 0.5s; }
.stagger.visible > *:nth-child(6) { transition-delay: 0.6s; }

.stagger.visible > * {
  opacity: 1;
  transform: translateY(0);
}

/* =============================================
   RESPONSIVE DESIGN
   ============================================= */
@media (max-width: 1024px) {
  .hero .container {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-content {
    max-width: 100%;
  }

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

  .hero-stats {
    justify-content: center;
  }

  .hero-visual {
    display: none;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .about-visual {
    max-width: 500px;
    margin: 0 auto;
  }

  .curriculum-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .benefits-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .instructor-card {
    grid-template-columns: 1fr;
    text-align: center;
    padding: 32px;
  }

  .instructor-image {
    max-width: 300px;
    margin: 0 auto;
  }

  .instructor-tags {
    justify-content: center;
  }

  .testimonials-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (max-width: 768px) {
  .section {
    padding: 60px 0;
  }

  .section-header {
    margin-bottom: 40px;
  }

  /* Hiện hamburger menu */
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--bg-white);
    flex-direction: column;
    padding: 24px;
    gap: 0;
    box-shadow: var(--shadow-lg);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-links li {
    width: 100%;
  }

  .nav-links a {
    display: block;
    padding: 12px 0;
    border-bottom: 1px solid var(--border-light);
  }

  .nav-links a::after {
    display: none;
  }

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

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

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

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

  .about-features {
    grid-template-columns: 1fr;
  }

  .about-visual {
    grid-template-columns: 1fr 1fr;
  }

  .hero-stats {
    gap: 24px;
    flex-wrap: wrap;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .modal {
    padding: 32px 24px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

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

  .hero-buttons .btn {
    width: 100%;
  }

  .about-visual {
    grid-template-columns: 1fr;
  }

  .about-stat-card:nth-child(2),
  .about-stat-card:nth-child(3) {
    transform: none;
  }

  .about-stat-card:nth-child(2):hover,
  .about-stat-card:nth-child(3):hover {
    transform: translateY(-4px);
  }
}