/* ============================================================
   TuTaiKhoan — PCCC Training Landing Page
   Design System & Styles
   ============================================================ */

/* --- CSS Custom Properties (Design Tokens) --- */
:root {
  /* Colors — Primary */
  --color-primary: #DC2626;
  --color-primary-dark: #B91C1C;
  --color-primary-light: #FEE2E2;
  --color-primary-hover: #EF4444;

  /* Colors — CTA / Energy */
  --color-cta: #F97316;
  --color-cta-dark: #EA580C;
  --color-cta-light: #FFEDD5;

  /* Colors — Neutral */
  --color-white: #FFFFFF;
  --color-bg: #F8FAFC;
  --color-bg-alt: #F1F5F9;
  --color-text: #0F172A;
  --color-text-muted: #475569;
  --color-text-light: #64748B;
  --color-border: #E2E8F0;
  --color-border-light: #F1F5F9;

  /* Colors — Dark Footer */
  --color-footer-bg: #0F172A;
  --color-footer-text: #94A3B8;
  --color-footer-heading: #F1F5F9;

  /* Typography */
  --font-heading: 'Be Vietnam Pro', sans-serif;
  --font-body: 'Open Sans', sans-serif;

  /* Spacing */
  --section-py: 5rem;
  --container-max: 80rem;
  --container-px: 1.5rem;
  --nav-height: 4.5rem;

  /* Borders & Radius */
  --radius-sm: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.25rem;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08), 0 2px 4px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.1), 0 4px 8px rgba(0, 0, 0, 0.06);
  --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.12);

  /* Transitions */
  --transition-fast: 200ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;

  /* Z-index layers */
  --z-back: -1;
  --z-base: 1;
  --z-dropdown: 30;
  --z-nav: 50;
  --z-overlay: 60;
  --z-modal: 70;
  --z-tooltip: 80;
  --z-toast: 100;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
  cursor: pointer;
}

button {
  cursor: pointer;
  font-family: inherit;
  border: none;
  background: none;
}

input,
select,
textarea,
button {
  font-family: inherit;
  font-size: inherit;
}

ul {
  list-style: none;
}

/* --- Focus Styles (Keyboard Navigation) --- */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 4px;
}

/* --- Container --- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding-left: var(--container-px);
  padding-right: var(--container-px);
}

/* --- Section Base --- */
.section {
  padding-top: var(--section-py);
  padding-bottom: var(--section-py);
}

.section-alt {
  background-color: var(--color-bg-alt);
}

.section-header {
  text-align: center;
  margin-bottom: 3.5rem;
}

.section-title {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.75rem;
  line-height: 1.2;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 36rem;
  margin: 0 auto;
  line-height: 1.6;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  cursor: pointer;
  white-space: nowrap;
  line-height: 1.4;
}

.btn-primary {
  background-color: var(--color-cta);
  color: var(--color-white);
  box-shadow: 0 4px 14px rgba(249, 115, 22, 0.35);
}

.btn-primary:hover {
  background-color: var(--color-cta-dark);
  box-shadow: 0 6px 20px rgba(249, 115, 22, 0.45);
  transform: translateY(-1px);
}

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

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

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

.btn-outline-light {
  background-color: transparent;
  color: var(--color-white);
  border: 2px solid rgba(255, 255, 255, 0.7);
}

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

.btn-sm {
  padding: 0.5rem 1.25rem;
  font-size: 0.875rem;
}

.btn-lg {
  padding: 1rem 2.25rem;
  font-size: 1.05rem;
}

.btn svg {
  width: 1.25rem;
  height: 1.25rem;
  flex-shrink: 0;
}

/* --- Floating Header / Navbar --- */
.header {
  position: fixed;
  top: 1rem;
  left: 1rem;
  right: 1rem;
  max-width: var(--container-max);
  margin: 0 auto;
  z-index: var(--z-nav);
  transition: all var(--transition-base);
}

.header-scrolled {
  top: 0.5rem;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.5rem;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
  border: 1px solid rgba(226, 232, 240, 0.6);
  transition: padding var(--transition-base);
}

.header-scrolled .header-inner {
  padding-top: 0.55rem;
  padding-bottom: 0.55rem;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  flex-shrink: 0;
}

.header-logo-icon {
  width: 2rem;
  height: 2rem;
  color: var(--color-primary);
}

.header-logo-text {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1;
}

.header-logo-text span {
  color: var(--color-primary);
}

/* --- Desktop Nav Menu --- */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.nav-link {
  padding: 0.5rem 0.875rem;
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  position: relative;
}

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

.nav-link.active {
  color: var(--color-primary);
  font-weight: 600;
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0.15rem;
  left: 50%;
  transform: translateX(-50%);
  width: 1.25rem;
  height: 2px;
  background-color: var(--color-primary);
  border-radius: 1px;
}

.nav-cta {
  margin-left: 0.75rem;
}

/* --- Mobile Menu Toggle --- */
.mobile-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-sm);
  gap: 5px;
  transition: background var(--transition-fast);
}

.mobile-toggle:hover {
  background-color: var(--color-primary-light);
}

.mobile-toggle-bar {
  display: block;
  width: 1.375rem;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 2px;
  transition: all var(--transition-base);
  transform-origin: center;
}

.mobile-toggle[aria-expanded="true"] .mobile-toggle-bar:nth-child(1) {
  transform: rotate(45deg) translate(4px, 6px);
}

.mobile-toggle[aria-expanded="true"] .mobile-toggle-bar:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.mobile-toggle[aria-expanded="true"] .mobile-toggle-bar:nth-child(3) {
  transform: rotate(-45deg) translate(4px, -6px);
}

/* --- Hero Section --- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, #B91C1C 0%, #DC2626 50%, #EF4444 100%);
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 20% 50%, rgba(255, 255, 255, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(255, 255, 255, 0.06) 0%, transparent 40%),
    radial-gradient(circle at 50% 80%, rgba(249, 115, 22, 0.15) 0%, transparent 50%);
  pointer-events: none;
}

.hero-pattern {
  position: absolute;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.04'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  pointer-events: none;
  opacity: 0.5;
}

.hero .container {
  position: relative;
  z-index: var(--z-base);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
  padding-top: 6rem;
  padding-bottom: 4rem;
}

.hero-content {
  color: var(--color-white);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 9999px;
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 1.5rem;
  backdrop-filter: blur(4px);
}

.hero-badge svg {
  width: 1rem;
  height: 1rem;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 1.25rem;
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: 1.1rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 2rem;
  max-width: 32rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.hero-image-placeholder {
  width: 100%;
  max-width: 28rem;
  aspect-ratio: 4/3;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.15) 0%, rgba(255, 255, 255, 0.05) 100%);
  border: 1px solid rgba(255, 255, 255, 0.15);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  color: rgba(255, 255, 255, 0.6);
  position: relative;
  overflow: hidden;
}

.hero-image-placeholder svg {
  width: 4rem;
  height: 4rem;
  opacity: 0.4;
}

.hero-image-placeholder span {
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.95rem;
}

.hero-image-placeholder::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 30% 40%, rgba(249, 115, 22, 0.1) 0%, transparent 60%);
  pointer-events: none;
}

/* Floating elements in hero visual */
.hero-float-icon {
  position: absolute;
  width: 3rem;
  height: 3rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255, 255, 255, 0.7);
  animation: float 4s ease-in-out infinite;
}

.hero-float-icon:nth-child(2) {
  top: 10%;
  right: 5%;
  animation-delay: 0.5s;
}

.hero-float-icon:nth-child(3) {
  bottom: 15%;
  left: 5%;
  animation-delay: 1.5s;
}

.hero-float-icon svg {
  width: 1.5rem;
  height: 1.5rem;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

/* --- Courses Section --- */
.courses-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.course-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-sm);
}

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

.course-card-icon {
  width: 3.25rem;
  height: 3.25rem;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
  color: var(--color-white);
  flex-shrink: 0;
}

.course-card-icon svg {
  width: 1.65rem;
  height: 1.65rem;
}

.course-card-icon.children {
  background: linear-gradient(135deg, #F97316, #DC2626);
}

.course-card-icon.family {
  background: linear-gradient(135deg, #DC2626, #B91C1C);
}

.course-card-icon.business {
  background: linear-gradient(135deg, #475569, #0F172A);
}

.course-card-title {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 1rem;
}

.course-card-features {
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
  margin-bottom: 1.5rem;
  flex: 1;
}

.course-card-features li {
  display: flex;
  align-items: flex-start;
  gap: 0.625rem;
  font-size: 0.925rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

.course-card-features li svg {
  width: 1.125rem;
  height: 1.125rem;
  color: var(--color-primary);
  flex-shrink: 0;
  margin-top: 0.2rem;
}

.course-card .btn {
  align-self: flex-start;
}

/* --- Benefits Section --- */
.benefits-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.75rem;
}

.benefit-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  text-align: center;
  transition: all var(--transition-base);
  box-shadow: var(--shadow-sm);
}

.benefit-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
  border-color: var(--color-border);
}

.benefit-card-icon {
  width: 3.5rem;
  height: 3.5rem;
  margin: 0 auto 1.25rem;
  border-radius: var(--radius-md);
  background: var(--color-primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  transition: all var(--transition-base);
}

.benefit-card:hover .benefit-card-icon {
  background: var(--color-primary);
  color: var(--color-white);
}

.benefit-card-icon svg {
  width: 1.75rem;
  height: 1.75rem;
}

.benefit-card-title {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.benefit-card-desc {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* --- Gallery Section --- */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

.gallery-card {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  aspect-ratio: 4 / 3;
  display: flex;
  align-items: flex-end;
  cursor: pointer;
  transition: all var(--transition-base);
  box-shadow: var(--shadow-sm);
}

.gallery-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
}

.gallery-card-bg {
  position: absolute;
  inset: 0;
  transition: transform var(--transition-slow);
}

.gallery-card:hover .gallery-card-bg {
  transform: scale(1.08);
}

.gallery-card-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.7) 0%, transparent 60%);
}

.gallery-card-label {
  position: relative;
  z-index: var(--z-base);
  padding: 1.25rem;
  color: var(--color-white);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.9rem;
  line-height: 1.4;
}

/* Individual gallery gradients */
.gallery-card:nth-child(1) .gallery-card-bg {
  background: linear-gradient(135deg, #DC2626 0%, #F97316 100%);
}

.gallery-card:nth-child(2) .gallery-card-bg {
  background: linear-gradient(135deg, #B91C1C 0%, #DC2626 100%);
}

.gallery-card:nth-child(3) .gallery-card-bg {
  background: linear-gradient(135deg, #F97316 0%, #EA580C 100%);
}

.gallery-card:nth-child(4) .gallery-card-bg {
  background: linear-gradient(135deg, #DC2626 0%, #991B1B 100%);
}

/* --- FAQ Section --- */
.faq-list {
  max-width: 48rem;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.faq-item {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: box-shadow var(--transition-base);
}

.faq-item:hover {
  box-shadow: var(--shadow-sm);
}

.faq-item.active {
  box-shadow: var(--shadow-sm);
  border-color: var(--color-primary-light);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.25rem 1.5rem;
  text-align: left;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-text);
  cursor: pointer;
  background: none;
  border: none;
  transition: color var(--transition-fast);
}

.faq-question:hover {
  color: var(--color-primary);
}

.faq-item.active .faq-question {
  color: var(--color-primary);
}

.faq-chevron {
  width: 1.25rem;
  height: 1.25rem;
  flex-shrink: 0;
  color: var(--color-text-light);
  transition: transform var(--transition-base);
}

.faq-item.active .faq-chevron {
  transform: rotate(180deg);
  color: var(--color-primary);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-slow), padding var(--transition-slow);
}

.faq-item.active .faq-answer {
  max-height: 20rem;
}

.faq-answer-inner {
  padding: 0 1.5rem 1.25rem;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* --- Contact Section --- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}

.contact-form-wrapper {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2.25rem;
  box-shadow: var(--shadow-sm);
}

.form-title {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  color: var(--color-text);
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-label {
  display: block;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.875rem;
  color: var(--color-text);
  margin-bottom: 0.375rem;
}

.form-input,
.form-select {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  color: var(--color-text);
  background: var(--color-white);
  transition: all var(--transition-fast);
  line-height: 1.5;
}

.form-input:hover,
.form-select:hover {
  border-color: var(--color-text-light);
}

.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.1);
}

.form-input.error,
.form-select.error {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.1);
}

.form-error {
  display: none;
  font-size: 0.8rem;
  color: var(--color-primary);
  margin-top: 0.3rem;
}

.form-input.error ~ .form-error,
.form-select.error ~ .form-error {
  display: block;
}

.form-submit {
  width: 100%;
  margin-top: 0.5rem;
}

.form-submit .btn {
  width: 100%;
}

/* Submit states */
.btn-loading {
  pointer-events: none;
  opacity: 0.85;
}

.btn-loading .btn-text {
  visibility: hidden;
}

.btn-loading .btn-spinner {
  display: block;
}

.btn-spinner {
  display: none;
  width: 1.25rem;
  height: 1.25rem;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: var(--color-white);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  position: absolute;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.btn-success {
  background-color: #16A34A !important;
  box-shadow: 0 4px 14px rgba(22, 163, 74, 0.35) !important;
}

.form-success {
  display: none;
  text-align: center;
  padding: 2rem;
}

.form-success.show {
  display: block;
}

.form-success-icon {
  width: 3rem;
  height: 3rem;
  color: #16A34A;
  margin: 0 auto 1rem;
}

.form-success-text {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.form-success-desc {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

/* Contact info */
.contact-info {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.contact-info-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
}

.contact-info-title {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--color-text);
}

.contact-info-detail {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  font-size: 0.925rem;
  color: var(--color-text-muted);
}

.contact-info-detail svg {
  width: 1.25rem;
  height: 1.25rem;
  color: var(--color-primary);
  flex-shrink: 0;
  margin-top: 0.15rem;
}

.contact-social {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.contact-social-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem 1.25rem;
  border-radius: var(--radius-md);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.9rem;
  transition: all var(--transition-base);
  border: 1.5px solid var(--color-border);
}

.contact-social-btn svg {
  width: 1.375rem;
  height: 1.375rem;
  flex-shrink: 0;
}

.contact-social-btn.zalo {
  color: #0068FF;
  border-color: #0068FF;
  background: rgba(0, 104, 255, 0.04);
}

.contact-social-btn.zalo:hover {
  background: #0068FF;
  color: var(--color-white);
}

.contact-social-btn.telegram {
  color: #0088CC;
  border-color: #0088CC;
  background: rgba(0, 136, 204, 0.04);
}

.contact-social-btn.telegram:hover {
  background: #0088CC;
  color: var(--color-white);
}

/* --- Footer --- */
.footer {
  background-color: var(--color-footer-bg);
  color: var(--color-footer-text);
  padding-top: 4rem;
  padding-bottom: 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1.5fr;
  gap: 3rem;
  padding-bottom: 3rem;
  border-bottom: 1px solid rgba(148, 163, 184, 0.15);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.625rem;
}

.footer-logo-icon {
  width: 2rem;
  height: 2rem;
  color: var(--color-primary);
}

.footer-logo-text {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-footer-heading);
}

.footer-logo-text span {
  color: var(--color-primary);
}

.footer-description {
  font-size: 0.9rem;
  line-height: 1.7;
  max-width: 24rem;
}

.footer-heading {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-footer-heading);
  margin-bottom: 1.25rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
}

.footer-link {
  font-size: 0.9rem;
  color: var(--color-footer-text);
  transition: color var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
}

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

.footer-link svg {
  width: 0.875rem;
  height: 0.875rem;
}

.footer-contact-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
  line-height: 1.6;
}

.footer-contact-item svg {
  width: 1.125rem;
  height: 1.125rem;
  color: var(--color-primary);
  flex-shrink: 0;
  margin-top: 0.2rem;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.5rem 0;
  font-size: 0.85rem;
  color: rgba(148, 163, 184, 0.6);
}

.footer-bottom-links {
  display: flex;
  gap: 1.5rem;
}

.footer-bottom-links a {
  transition: color var(--transition-fast);
}

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

/* --- Back to Top Button --- */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: var(--z-tooltip);
  width: 3rem;
  height: 3rem;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  transition: all var(--transition-base);
  opacity: 0;
  visibility: hidden;
  transform: translateY(1rem);
  cursor: pointer;
  border: none;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-xl);
}

.back-to-top:active {
  transform: translateY(0);
}

.back-to-top svg {
  width: 1.25rem;
  height: 1.25rem;
}

/* --- Scroll Reveal Animation --- */
.reveal {
  opacity: 0;
  transform: translateY(2rem);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- Responsive: Tablet (768px - 1023px) --- */
@media (max-width: 1023px) {
  .courses-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

  .contact-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }

  .hero .container {
    grid-template-columns: 1fr;
    text-align: center;
    padding-top: 7rem;
  }

  .hero-subtitle {
    margin: 0 auto 2rem;
  }

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

  .hero-visual {
    display: none;
  }
}

/* --- Responsive: Mobile (< 768px) --- */
@media (max-width: 767px) {
  :root {
    --container-px: 1.25rem;
    --section-py: 3.5rem;
  }

  .header-inner {
    padding: 0.625rem 1.125rem;
  }

  .header-logo-text {
    font-size: 1.1rem;
  }

  /* Mobile nav: hidden by default */
  .mobile-toggle {
    display: flex;
  }

  .nav-menu {
    position: absolute;
    top: calc(100% + 0.5rem);
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
    flex-direction: column;
    padding: 0.75rem;
    gap: 0.25rem;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-0.5rem);
    transition: all var(--transition-base);
  }

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

  .nav-link {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 0.95rem;
  }

  .nav-cta {
    width: 100%;
    margin-left: 0;
    margin-top: 0.25rem;
  }

  .nav-cta .btn {
    width: 100%;
  }

  .nav-link.active::after {
    display: none;
  }

  .courses-grid {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }

  .benefits-grid {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }

  .gallery-grid {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 0.75rem;
    text-align: center;
  }

  .footer-bottom-links {
    gap: 1rem;
  }

  .hero-title {
    font-size: clamp(1.6rem, 7vw, 2rem);
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

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

  .contact-form-wrapper {
    padding: 1.5rem;
  }

  .back-to-top {
    bottom: 1.25rem;
    right: 1.25rem;
    width: 2.75rem;
    height: 2.75rem;
  }
}

/* --- Small Mobile (< 375px) --- */
@media (max-width: 374px) {
  .header-logo-text {
    font-size: 1rem;
  }

  .section-title {
    font-size: 1.5rem;
  }

  .course-card {
    padding: 1.5rem;
  }

  .benefit-card {
    padding: 1.5rem;
  }
}