/* ==========================================================================
   GO4AI FOUNDING TALENT CHALLENGE 2026 — DESIGN SYSTEM & STYLES
   Source: b2b.go4ai.org design tokens (Live extract 2026-10-14)
   ========================================================================== */

/* 1. DESIGN TOKENS */
:root {
  /* Nền / neutral */
  --white: #ffffff;
  --gray-50: #f2f6f5;
  --gray-100: #d9dfde;
  --gray-200: #bec9c6;
  --gray-300: #a5b2af;
  --gray-400: #8b9a96;
  --gray-500: #73817e;
  --gray-600: #5c6764;
  --gray-700: #454e4c;
  --gray-800: #2e3332;
  --gray-900: #15171a;

  /* Cam thương hiệu (hành động/CTA) */
  --coral-50: #fbeeec;
  --coral-100: #f6dad5;
  --coral-200: #ebb5ab;
  --coral-300: #e69786;
  --coral-400: #e06f68;
  --coral-500: #ce3c2b;
  --coral-600: #b8351f;

  /* Xanh lá (bằng chứng/tăng trưởng) */
  --green-50: #c4ece1;
  --green-100: #c4ece1;
  --green-200: #93dcc8;
  --green-300: #60c7ac;
  --green-400: #37a88a;
  --green-500: #08906c;
  --green-600: #077c5d;
  --green-700: #06694f;

  /* Xanh dương (uy tín/chứng thực) */
  --blue-50: #ebf5f9;
  --blue-100: #d8ebf4;
  --blue-200: #b0d4e8;
  --blue-300: #87bbd9;
  --blue-400: #66a7cc;
  --blue-500: #478fb8;
  --blue-700: #2b4d60;

  /* Chữ */
  --font-sans: 'Archivo', Arial, sans-serif;
  --font-mono: 'Azeret Mono', Arial, sans-serif;
  --title-xl: 4.5rem;    /* 72px */
  --title-l: 3.625rem;   /* 58px */
  --title-m: 2.25rem;    /* 36px */
  --title-s: 1.75rem;    /* 28px */
  --title-xs: 1.375rem;  /* 22px */
  --text-xl: 1.25rem;    /* 20px */
  --text-l: 1.125rem;    /* 18px */
  --text-m: 1rem;        /* 16px */
  --text-s: 0.875rem;    /* 14px */

  /* Khối & Bo góc */
  --radius-btn: 5rem;
  --radius-card: 1.5rem;  /* 24px */
  --radius-sm: 1rem;      /* 16px */
  --radius-md: 0.75rem;   /* 12px */
  --container: 85rem;     /* 1360px */
  --pad-x: 2.5rem;        /* 40px */

  /* Khoảng cách bội số 4px */
  --s-4: 0.25rem;
  --s-8: 0.5rem;
  --s-12: 0.75rem;
  --s-16: 1rem;
  --s-20: 1.25rem;
  --s-24: 1.5rem;
  --s-32: 2rem;
  --s-40: 2.5rem;
  --s-48: 3rem;
  --s-60: 3.75rem;
  --s-80: 5rem;
  --s-100: 6.25rem;
  --s-120: 7.5rem;

  /* Gradient & Transition */
  --grad-green: linear-gradient(265.26deg, #08906c 38.04%, #1f9c7b 94.86%);
  --grad-dark: linear-gradient(248deg, #03322a 16%, #06694f);
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* 2. RESET & BASE */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--gray-50);
  color: var(--gray-900);
}

body {
  font-family: var(--font-sans);
  background-color: var(--gray-50);
  color: var(--gray-900);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Reading Progress Bar */
.reading-progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: var(--grad-green);
  z-index: 9999;
  transition: width 0.1s linear;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--gray-50);
}
::-webkit-scrollbar-thumb {
  background: var(--gray-300);
  border-radius: var(--radius-btn);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--green-500);
}

/* 3. TYPOGRAPHY RULES */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: 500;
  line-height: 1.2;
  color: var(--gray-900);
}

strong, b {
  font-weight: 500;
}

p {
  line-height: 1.6;
}

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

/* 3.1 FOCUS-VISIBLE (MOTION.md §4, WCAG 2.1 AA) */
a:focus-visible,
button:focus-visible,
summary:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--gray-900);
  outline-offset: 2px;
}

#ve-go4ai a:focus-visible,
#ve-go4ai button:focus-visible,
footer a:focus-visible,
footer button:focus-visible {
  outline: 2px solid var(--white);
  outline-offset: 2px;
}

.form-input:focus-visible,
.form-select:focus-visible,
.form-textarea:focus-visible,
.faq-search-input:focus-visible {
  outline: 2px solid var(--green-500);
  outline-offset: 1px;
}

.mono {
  font-family: var(--font-mono);
}

.container {
  width: 100%;
  max-width: var(--container);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--pad-x);
  padding-right: var(--pad-x);
}

.section-lead {
  font-size: var(--text-l);
  color: var(--gray-600);
  max-width: 45rem; /* ~720px */
  margin-top: var(--s-16);
  margin-bottom: var(--s-48);
  text-align: left;
}

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-s);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--gray-600);
  margin-bottom: var(--s-16);
}

/* 4. BUTTONS & CHIPS */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-sans);
  font-weight: 500;
  font-size: var(--text-m);
  border-radius: var(--radius-btn);
  border: 1px solid transparent;
  padding: var(--s-16) var(--s-32);
  min-height: 48px;
  cursor: pointer;
  transition: transform 0.2s var(--ease), background-color 0.2s var(--ease), color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.btn-coral {
  background-color: var(--coral-500);
  color: var(--white);
  border-color: var(--coral-500);
}

.btn-coral:hover {
  background-color: var(--coral-600);
  border-color: var(--coral-600);
}

.btn-outline-green {
  background-color: transparent;
  color: var(--green-500);
  border-color: var(--green-500);
}

.btn-outline-green:hover {
  background-color: var(--green-50);
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: var(--s-4) var(--s-12);
  border-radius: var(--radius-btn);
  font-family: var(--font-mono);
  font-size: var(--text-s);
  font-weight: 500;
}

.badge-coral {
  background-color: var(--coral-50);
  color: var(--coral-500);
  border: 1px solid var(--coral-200);
}

.badge-green {
  background-color: var(--green-50);
  color: var(--green-600);
  border: 1px solid var(--green-200);
}

.badge-blue {
  background-color: var(--blue-50);
  color: var(--blue-700);
  border: 1px solid var(--blue-200);
}

/* 5. HEADER (Sticky) */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 64px;
  background-color: var(--gray-50);
  border-bottom: 1px solid var(--gray-100);
  transition: backdrop-filter 0.3s var(--ease), background-color 0.3s var(--ease);
}

.site-header.scrolled {
  background-color: rgba(242, 246, 245, 0.94);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: var(--s-16);
}

.header-brand {
  display: flex;
  align-items: center;
  gap: var(--s-16);
}

.header-brand-link {
  display: flex;
  align-items: center;
  gap: var(--s-12);
  text-decoration: none;
}

.brand-logo-img {
  height: 38px;
  width: auto;
  object-fit: contain;
  display: block;
}

.logo-text {
  font-size: var(--title-xs);
  font-weight: 500;
  letter-spacing: -0.02em;
  color: var(--gray-900);
}

.logo-tagline {
  font-family: var(--font-mono);
  font-size: var(--text-s);
  color: var(--gray-600);
  border-left: 1px solid var(--gray-200);
  padding-left: var(--s-12);
  display: inline-block;
}

.header-btn {
  padding: var(--s-8) var(--s-20);
  min-height: 44px;
  font-size: var(--text-s);
}

section[id] {
  scroll-margin-top: calc(64px + var(--s-16));
}

/* 6. SECTION 01: #hero */
.hero-section {
  background-color: var(--gray-50);
  background-image:
    radial-gradient(1100px circle at 50% -10%, rgba(8, 144, 108, 0.08) 0%, transparent 65%),
    radial-gradient(900px circle at 85% 60%, rgba(71, 143, 184, 0.06) 0%, transparent 60%),
    linear-gradient(to right, rgba(190, 201, 198, 0.22) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(190, 201, 198, 0.22) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 48px 48px, 48px 48px;
  padding-top: var(--s-80);
  padding-bottom: var(--s-80);
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--gray-200);
}

.hero-neural-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1;
}

.hero-section .container {
  position: relative;
  z-index: 2;
}

/* Hero Badge Wrap & Live Radar Beacon */
.hero-badge-wrap {
  display: inline-flex;
  align-items: center;
  gap: var(--s-12);
  margin-bottom: var(--s-20);
  padding: 0.375rem var(--s-16);
  background-color: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-btn);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.hero-badge-wrap .eyebrow {
  margin-bottom: 0;
  color: var(--gray-800);
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
}

.radar-beacon {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 10px;
  height: 10px;
  flex-shrink: 0;
}

.radar-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--green-500);
}

.radar-ping {
  position: absolute;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 1px solid var(--green-400);
  animation: radar-pulse 2s infinite cubic-bezier(0, 0, 0.2, 1);
}

@keyframes radar-pulse {
  0% { transform: scale(0.5); opacity: 1; }
  100% { transform: scale(2.2); opacity: 0; }
}

/* Two-column Hero Layout */
.hero-layout {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: var(--s-48);
  margin-bottom: var(--s-60);
}

.hero-title {
  font-size: var(--title-xl);
  font-weight: 500;
  letter-spacing: -0.03em;
  line-height: 1.12;
  margin-bottom: var(--s-24);
  max-width: 44rem;
}

.hero-title .title-line-1 {
  display: block;
  color: var(--gray-900);
}

.hero-title .headline-gradient {
  display: block;
  background: var(--grad-green);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-lead {
  font-size: var(--text-xl);
  color: var(--gray-600);
  max-width: 42rem;
  line-height: 1.6;
  margin-bottom: var(--s-40);
}

.hero-cta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--s-24);
}

.deadline-pill {
  font-family: var(--font-mono);
  font-size: var(--text-s);
  color: var(--coral-500);
  background-color: var(--coral-50);
  border: 1px solid var(--coral-200);
  padding: var(--s-12) var(--s-24);
  border-radius: var(--radius-btn);
  font-weight: 500;
}

/* High-Tech AI System Architecture HUD */
.hero-hud-card {
  position: relative;
  background-color: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-card);
  padding: var(--s-24);
  box-shadow: 0 12px 32px -8px rgba(8, 144, 108, 0.08);
  overflow: hidden;
}

.hud-corner {
  position: absolute;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--gray-300);
  line-height: 1;
  pointer-events: none;
}

.hud-corner-tl { top: 8px; left: 10px; }
.hud-corner-tr { top: 8px; right: 10px; }
.hud-corner-bl { bottom: 8px; left: 10px; }
.hud-corner-br { bottom: 8px; right: 10px; }

.hud-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--s-16);
  padding-bottom: var(--s-12);
  border-bottom: 1px solid var(--gray-100);
}

.hud-status {
  display: flex;
  align-items: center;
  gap: var(--s-8);
}

.hud-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--green-500);
}

.hud-title {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  color: var(--gray-700);
  text-transform: uppercase;
}

.hud-badge {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  padding: 0.125rem 0.5rem;
  background-color: var(--green-50);
  color: var(--green-600);
  border: 1px solid var(--green-200);
  border-radius: var(--radius-btn);
}

.hud-diagram-wrap {
  width: 100%;
  display: flex;
  justify-content: center;
}

.hud-diagram-svg {
  width: 100%;
  max-width: 360px;
  height: auto;
  display: block;
}

.hud-orbit-outer {
  transform-origin: 190px 170px;
  animation: hud-spin-reverse 45s linear infinite;
}

.hud-orbit-inner {
  transform-origin: 190px 170px;
  animation: hud-spin 30s linear infinite;
}

@keyframes hud-spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

@keyframes hud-spin-reverse {
  from { transform: rotate(0deg); }
  to { transform: rotate(-360deg); }
}

.hud-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-12);
  margin-top: var(--s-16);
  padding-top: var(--s-12);
  border-top: 1px solid var(--gray-100);
}

.hud-telemetry {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--gray-600);
  letter-spacing: 0.04em;
}

/* High-tech Roadmap Preview Card */
.hero-metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--s-24);
}

.metric-card {
  background-color: var(--white);
  border: 1px solid var(--gray-200);
  border-top: 3px solid var(--green-500);
  border-radius: var(--radius-card);
  padding: var(--s-32);
  display: flex;
  flex-direction: column;
  gap: var(--s-8);
  position: relative;
  overflow: hidden;
  box-shadow: 0 4px 16px -4px rgba(0, 0, 0, 0.04);
  transition: border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.metric-card:nth-child(2) {
  border-top-color: var(--blue-500);
}

.metric-card:nth-child(3) {
  border-top-color: var(--coral-500);
}

.metric-param {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--gray-500);
  margin-bottom: var(--s-4);
  display: flex;
  align-items: center;
  gap: var(--s-8);
}

.metric-param-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--green-500);
  display: inline-block;
}

.metric-card:nth-child(2) .metric-param-dot {
  background-color: var(--blue-500);
}

.metric-card:nth-child(3) .metric-param-dot {
  background-color: var(--coral-500);
}

.metric-number {
  font-family: var(--font-sans);
  font-size: var(--title-m);
  font-weight: 500;
  color: var(--gray-900);
  line-height: 1.2;
}

.metric-label {
  font-size: var(--text-s);
  color: var(--gray-600);
  line-height: 1.5;
}

/* Dynamic Card Spotlight Effect */
.metric-card::before,
.benefit-card::before,
.timeline-card::before,
.track-card::before,
.capability-card::before,
.stat-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: radial-gradient(350px circle at var(--mouse-x, -999px) var(--mouse-y, -999px), rgba(8, 144, 108, 0.09), transparent 70%);
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.3s var(--ease);
  z-index: 0;
}

.metric-card:hover::before,
.benefit-card:hover::before,
.timeline-card:hover::before,
.track-card:hover::before,
.capability-card:hover::before,
.stat-card:hover::before {
  opacity: 1;
}

.metric-card:hover,
.benefit-card:hover,
.timeline-card:hover,
.track-card:hover {
  border-color: var(--green-300);
  box-shadow: 0 8px 24px -6px rgba(8, 144, 108, 0.1);
}

@media (max-width: 1024px) {
  .hero-layout {
    grid-template-columns: 1fr;
    gap: var(--s-40);
  }
  .hero-hud-card {
    max-width: 480px;
    margin: 0 auto;
  }
}

@media (max-width: 768px) {
  .hero-metrics {
    grid-template-columns: 1fr;
  }
  .hero-title {
    font-size: var(--title-l);
  }
}

/* 7. SECTION 02: #quyen-loi */
.benefits-section {
  background-color: var(--white);
  padding-top: var(--s-100);
  padding-bottom: var(--s-100);
}

.section-title {
  font-size: var(--title-l);
  font-weight: 500;
  letter-spacing: -0.02em;
  color: var(--gray-900);
}

.benefits-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--s-24);
}

.benefit-card {
  background-color: var(--gray-50);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-card);
  padding: var(--s-32);
  display: flex;
  flex-direction: column;
  gap: var(--s-16);
}

.benefit-card-full {
  grid-column: 1 / -1;
}

.card-index {
  font-family: var(--font-mono);
  font-size: var(--text-m);
  color: var(--green-500);
  font-weight: 500;
}

.benefit-card-title {
  font-size: var(--title-s);
  font-weight: 500;
  color: var(--gray-900);
  line-height: 1.3;
}

.benefit-card-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-s);
  color: var(--green-600);
  background-color: var(--green-50);
  border: 1px solid var(--green-200);
  padding: var(--s-4) var(--s-12);
  border-radius: var(--radius-btn);
  width: fit-content;
}

.benefit-card-text {
  font-size: var(--text-m);
  color: var(--gray-700);
  line-height: 1.6;
}

.venture-chips {
  display: flex;
  flex-direction: column;
  gap: var(--s-12);
  margin-top: var(--s-8);
  margin-bottom: var(--s-8);
}

.chip-item {
  background-color: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-sm);
  padding: var(--s-16) var(--s-20);
  font-size: var(--text-m);
  color: var(--gray-800);
  line-height: 1.5;
}

.chip-title {
  font-family: var(--font-mono);
  font-weight: 500;
  color: var(--blue-700);
  margin-right: var(--s-8);
}

.benefit-disclaimer {
  font-size: var(--text-s);
  color: var(--gray-500);
  line-height: 1.5;
}

/* 8. SECTION 03: #hanh-trinh */
.journey-section {
  background-color: var(--gray-50);
  padding-top: var(--s-100);
  padding-bottom: var(--s-100);
}

.timeline {
  display: flex;
  flex-direction: column;
  gap: var(--s-32);
  position: relative;
  max-width: 58rem;
  margin-bottom: var(--s-48);
}

.timeline-card {
  background-color: var(--white);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-card);
  padding: var(--s-40);
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--s-16);
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.timeline-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(21, 23, 26, 0.05);
}

.round-badge {
  font-family: var(--font-mono);
  font-size: var(--text-s);
  font-weight: 500;
  color: var(--coral-500);
  background-color: var(--coral-50);
  border: 1px solid var(--coral-200);
  padding: var(--s-4) var(--s-12);
  border-radius: var(--radius-btn);
  width: fit-content;
}

.round-question {
  font-size: var(--title-xs);
  font-weight: 500;
  color: var(--gray-900);
  line-height: 1.4;
}

.round-desc {
  font-size: var(--text-m);
  color: var(--gray-700);
  line-height: 1.6;
}

.round-sublist {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--s-8);
  margin-top: var(--s-8);
}

.round-sublist li {
  font-size: var(--text-m);
  color: var(--gray-700);
  padding-left: var(--s-16);
  position: relative;
}

.round-sublist li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--green-500);
}

.round-meta {
  display: flex;
  flex-direction: column;
  gap: var(--s-8);
  padding-top: var(--s-16);
  border-top: 1px solid var(--gray-100);
  font-size: var(--text-s);
}

.meta-item {
  color: var(--gray-600);
}

.meta-highlight {
  font-weight: 500;
  color: var(--gray-900);
}

/* 9. SECTION 04: #doi-tuong */
.audience-section {
  background-color: var(--white);
  padding-top: var(--s-100);
  padding-bottom: var(--s-100);
}

.tracks-heading {
  font-family: var(--font-mono);
  font-size: var(--text-m);
  font-weight: 500;
  color: var(--green-600);
  margin-bottom: var(--s-24);
}

.tracks-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--s-24);
  margin-bottom: var(--s-48);
}

.track-card {
  background-color: var(--gray-50);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-card);
  padding: var(--s-32);
  display: flex;
  flex-direction: column;
  gap: var(--s-12);
}

.track-title {
  font-family: var(--font-sans);
  font-size: var(--title-xs);
  font-weight: 500;
  color: var(--gray-900);
  line-height: 1.3;
}

.track-desc {
  font-size: var(--text-m);
  color: var(--gray-700);
  line-height: 1.6;
}

.values-banner {
  background-color: var(--blue-50);
  border: 1px solid var(--blue-200);
  border-radius: var(--radius-card);
  padding: var(--s-32);
  margin-bottom: var(--s-24);
}

.values-title {
  font-family: var(--font-mono);
  font-size: var(--text-s);
  font-weight: 500;
  color: var(--blue-700);
  margin-bottom: var(--s-12);
}

.values-list {
  font-family: var(--font-sans);
  font-size: var(--text-l);
  font-weight: 500;
  color: var(--blue-700);
  line-height: 1.6;
}

.audience-outro {
  font-size: var(--text-m);
  color: var(--gray-600);
  max-width: 45rem;
}

/* 10. SECTION 05: #ve-go4ai (Nền tối DUY NHẤT) */
.about-section {
  background: var(--grad-dark);
  color: var(--white);
  padding-top: var(--s-100);
  padding-bottom: var(--s-100);
}

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

.about-section .section-lead {
  color: var(--gray-200);
}

.about-intro-box {
  margin-bottom: var(--s-48);
  max-width: 48rem;
}

.about-eyebrow {
  font-family: var(--font-mono);
  font-size: var(--text-s);
  color: var(--green-300);
  margin-bottom: var(--s-12);
}

.about-intro-text {
  font-size: var(--text-l);
  color: var(--gray-100);
  line-height: 1.6;
  margin-bottom: var(--s-24);
}

.about-subheading {
  font-size: var(--text-m);
  color: var(--green-300);
  font-weight: 500;
  margin-bottom: var(--s-16);
}

.capabilities-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--s-24);
  margin-bottom: var(--s-60);
}

.capability-card {
  background-color: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--green-600);
  border-radius: var(--radius-card);
  padding: var(--s-32);
  display: flex;
  flex-direction: column;
  gap: var(--s-12);
}

.capability-title {
  font-size: var(--title-xs);
  font-weight: 500;
  color: var(--white);
}

.capability-desc {
  font-size: var(--text-m);
  color: var(--gray-200);
  line-height: 1.6;
}

.stats-heading {
  font-family: var(--font-mono);
  font-size: var(--text-m);
  font-weight: 500;
  color: var(--green-300);
  margin-bottom: var(--s-24);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--s-24);
  margin-bottom: var(--s-32);
}

.stat-card {
  background-color: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--green-600);
  border-radius: var(--radius-card);
  padding: var(--s-32);
  display: flex;
  flex-direction: column;
  gap: var(--s-8);
}

.stat-number {
  font-family: var(--font-sans);
  font-size: var(--title-m);
  font-weight: 500;
  color: var(--green-300);
  line-height: 1.2;
}

.stat-label {
  font-size: var(--text-s);
  color: var(--gray-200);
}

.stats-tagline {
  font-family: var(--font-mono);
  font-size: var(--text-s);
  color: var(--green-300);
  margin-bottom: var(--s-20);
}

.about-outro {
  font-size: var(--text-m);
  color: var(--gray-200);
  max-width: 48rem;
  line-height: 1.6;
}

/* Logo Marquee in About Section */
.logos__section {
  margin-top: var(--s-32);
  margin-bottom: var(--s-40);
  width: 100%;
}

.logos__row {
  overflow: hidden;
  position: relative;
  width: 100%;
  padding-top: var(--s-8);
  padding-bottom: var(--s-8);
  mask-image: linear-gradient(to right, transparent 0%, black 10%, black 90%, transparent 100%);
  -webkit-mask-image: linear-gradient(to right, transparent 0%, black 10%, black 90%, transparent 100%);
}

.logos__row + .logos__row {
  margin-top: var(--s-16);
}

.logos__track {
  display: flex;
  align-items: center;
  width: max-content;
  will-change: transform;
}

.logos__track.is--ltr {
  animation: marquee-ltr 32s linear infinite;
}

.logos__track.is--rtl {
  animation: marquee-rtl 32s linear infinite;
}

.logos__row:hover .logos__track,
.logos__row:focus-within .logos__track {
  animation-play-state: paused;
}

.logos__item {
  width: 160px;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--s-8) var(--s-16);
  margin-right: var(--s-16);
  background-color: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-sm);
  transition: transform 0.2s var(--ease), border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
  flex-shrink: 0;
}

.logos__item:hover {
  transform: translateY(-2px);
  border-color: var(--green-300);
  box-shadow: 0 4px 12px rgba(3, 50, 42, 0.15);
}

.logos__img {
  max-width: 120px;
  max-height: 44px;
  object-fit: contain;
  filter: none;
  opacity: 1;
  transition: transform 0.2s var(--ease);
}

.logos__item:hover .logos__img {
  transform: scale(1.06);
}

@keyframes marquee-ltr {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

@keyframes marquee-rtl {
  0% { transform: translateX(-50%); }
  100% { transform: translateX(0); }
}

/* Non-clickable Cards: no hover elevation (MOTION.md §4) */
.benefit-card,
.track-card,
.metric-card,
.stat-card {
  transition: border-color 0.25s var(--ease);
}

/* 11. SECTION 06: #lich-trinh */
.schedule-faq-section {
  background-color: var(--gray-50);
  padding-top: var(--s-100);
  padding-bottom: var(--s-100);
}

.sub-section-heading {
  font-family: var(--font-mono);
  font-size: var(--text-m);
  font-weight: 500;
  color: var(--green-600);
  margin-bottom: var(--s-24);
}

.table-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  background-color: var(--white);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-card);
  margin-bottom: var(--s-16);
}

.schedule-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
}

.schedule-table th,
.schedule-table td {
  padding: var(--s-16) var(--s-24);
  border-bottom: 1px solid var(--gray-100);
}

.schedule-table th {
  background-color: var(--gray-50);
  font-family: var(--font-mono);
  font-size: var(--text-s);
  font-weight: 500;
  color: var(--gray-700);
}

.schedule-table tr:last-child td {
  border-bottom: none;
}

.schedule-table td:first-child {
  font-weight: 500;
  color: var(--gray-900);
}

.schedule-table td:last-child {
  color: var(--gray-600);
  font-family: var(--font-mono);
  font-size: var(--text-s);
}

.table-note {
  font-size: var(--text-s);
  color: var(--gray-500);
  line-height: 1.5;
  margin-bottom: var(--s-60);
  max-width: 48rem;
}

/* FAQ Accordion */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: var(--s-16);
  max-width: 54rem;
}

.faq-item {
  background-color: var(--white);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-card);
  overflow: hidden;
  transition: border-color 0.2s var(--ease);
}

.faq-item.active {
  border-color: var(--gray-300);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--s-24);
  background: none;
  border: none;
  font-family: var(--font-sans);
  font-size: var(--title-xs);
  font-weight: 500;
  color: var(--gray-900);
  text-align: left;
  cursor: pointer;
  gap: var(--s-16);
  min-height: 48px;
  transition: color 0.3s var(--ease);
}

.faq-question:hover {
  color: var(--blue-700);
}

.faq-icon {
  font-family: var(--font-mono);
  font-size: var(--title-xs);
  color: var(--green-500);
  transition: transform 0.2s var(--ease);
  flex-shrink: 0;
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s var(--ease), padding 0.3s var(--ease);
  padding: 0 var(--s-24);
}

.faq-item.active .faq-answer {
  padding-bottom: var(--s-24);
}

.faq-answer-inner {
  font-size: var(--text-m);
  color: var(--gray-700);
  line-height: 1.6;
}

/* 12. SECTION 07: #dang-ky */
.register-section {
  background-color: var(--white);
  padding-top: var(--s-100);
  padding-bottom: var(--s-100);
}

.deadline-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-s);
  font-weight: 500;
  color: var(--coral-500);
  background-color: var(--coral-50);
  border: 1px solid var(--coral-200);
  padding: var(--s-8) var(--s-16);
  border-radius: var(--radius-btn);
  margin-bottom: var(--s-32);
}

.form-wrapper {
  background-color: var(--gray-50);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-card);
  padding: var(--s-48);
  max-width: 52rem;
}

.form-header-title {
  font-size: var(--title-s);
  font-weight: 500;
  color: var(--gray-900);
  margin-bottom: var(--s-8);
}

.form-header-sub {
  font-size: var(--text-s);
  color: var(--gray-600);
  margin-bottom: var(--s-32);
}

.registration-form {
  display: flex;
  flex-direction: column;
  gap: var(--s-24);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--s-8);
}

.form-label {
  font-size: var(--text-m);
  font-weight: 500;
  color: var(--gray-800);
}

.required-star {
  color: var(--coral-500);
}

.form-helper {
  font-size: var(--text-s);
  color: var(--gray-500);
  line-height: 1.4;
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  font-family: var(--font-sans);
  font-size: var(--text-m);
  color: var(--gray-900);
  background-color: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-md);
  padding: var(--s-12) var(--s-16);
  transition: border-color 0.2s var(--ease);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--green-500);
}

.form-input:user-invalid,
.form-textarea:user-invalid {
  border-color: var(--coral-500);
}

.form-textarea {
  min-height: 100px;
  resize: vertical;
}

.radio-group {
  display: flex;
  flex-direction: column;
  gap: var(--s-8);
  margin-top: var(--s-4);
}

.radio-label,
.checkbox-label {
  display: flex;
  align-items: flex-start;
  gap: var(--s-12);
  padding: var(--s-12) var(--s-16);
  background-color: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-md);
  font-size: var(--text-m);
  color: var(--gray-800);
  cursor: pointer;
  line-height: 1.5;
  transition: all 0.2s var(--ease);
}

.radio-label:hover,
.checkbox-label:hover {
  border-color: var(--green-300);
  background-color: var(--green-50);
}

.radio-label:has(input:checked),
.checkbox-label:has(input:checked) {
  border-color: var(--green-500);
  background-color: var(--green-50);
  color: var(--green-700);
}

.radio-label input[type="radio"],
.checkbox-label input[type="checkbox"] {
  accent-color: var(--green-500);
  width: 1.125rem;
  height: 1.125rem;
  margin-top: 0.2rem;
  flex-shrink: 0;
}

.checkbox-group {
  display: flex;
  flex-direction: column;
  gap: var(--s-12);
  margin-top: var(--s-4);
}

.form-disclaimer {
  font-size: var(--text-s);
  color: var(--gray-500);
  margin-top: var(--s-8);
  margin-bottom: var(--s-8);
  line-height: 1.5;
}

.submit-btn {
  width: 100%;
  max-width: 20rem;
  align-self: flex-start;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--s-8);
}

/* Floating Scroll to Top Button */
.scroll-top-btn {
  position: fixed;
  bottom: var(--s-24);
  right: var(--s-24);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--white);
  border: 1px solid var(--gray-200);
  color: var(--gray-800);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px rgba(21, 23, 26, 0.12);
  cursor: pointer;
  z-index: 90;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s var(--ease), visibility 0.3s var(--ease), transform 0.2s var(--ease), background-color 0.2s var(--ease);
}

.scroll-top-btn.visible {
  opacity: 1;
  visibility: visible;
}

.scroll-top-btn:hover {
  transform: translateY(-3px);
  background-color: var(--green-50);
  color: var(--green-600);
  border-color: var(--green-300);
}

/* Success notification block */
.submission-success {
  display: none;
  background-color: var(--green-50);
  border: 1px solid var(--green-200);
  border-radius: var(--radius-card);
  padding: var(--s-40);
  max-width: 52rem;
  margin-top: var(--s-24);
  flex-direction: column;
  gap: var(--s-16);
}

.submission-success.visible {
  display: flex;
}

.success-title {
  font-family: var(--font-sans);
  font-size: var(--title-s);
  font-weight: 500;
  color: var(--green-700);
}

.success-text {
  font-size: var(--text-m);
  color: var(--gray-800);
  line-height: 1.6;
}

.success-status {
  font-family: var(--font-mono);
  font-size: var(--text-s);
  font-weight: 500;
  color: var(--green-600);
  background-color: var(--white);
  border: 1px solid var(--green-200);
  padding: var(--s-8) var(--s-16);
  border-radius: var(--radius-sm);
  width: fit-content;
}

.success-btn {
  align-self: flex-start;
}

/* 13. FOOTER */
.site-footer {
  background-color: var(--gray-900);
  color: var(--gray-300);
  padding-top: var(--s-80);
  padding-bottom: var(--s-60);
  border-top: 1px solid var(--gray-800);
}

.footer-top {
  display: flex;
  flex-direction: column;
  gap: var(--s-16);
  margin-bottom: var(--s-40);
  border-bottom: 1px solid var(--gray-800);
  padding-bottom: var(--s-32);
}

.footer-brand-wrap {
  display: flex;
  align-items: center;
  gap: var(--s-16);
}

.footer-logo-img {
  height: 48px;
  width: auto;
  object-fit: contain;
  display: block;
}

.footer-brand {
  font-size: var(--title-s);
  font-weight: 500;
  color: var(--white);
}

.footer-program {
  font-family: var(--font-mono);
  font-size: var(--text-m);
  color: var(--gray-400);
}

.footer-info {
  display: flex;
  flex-direction: column;
  gap: var(--s-8);
  font-size: var(--text-s);
  color: var(--gray-300);
  line-height: 1.6;
}

.footer-info a {
  color: var(--green-300);
}

.footer-info a:hover {
  text-decoration: underline;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-16);
  margin-top: var(--s-16);
  margin-bottom: var(--s-24);
  font-size: var(--text-s);
  color: var(--green-300);
}

.footer-links a:hover {
  text-decoration: underline;
}

.footer-disclaimer {
  font-size: var(--text-s);
  color: var(--gray-400);
  line-height: 1.6;
}

/* 14. MOTION & ANIMATION (with prefers-reduced-motion) */
@media (prefers-reduced-motion: no-preference) {
  html.motion-ready .fade-up {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s var(--ease), transform 0.5s var(--ease);
  }

  html.motion-ready .fade-up.in-view {
    opacity: 1;
    transform: translateY(0);
  }

  /* Stagger delays for grid / group items (MOTION.md §3 & §5) */
  html.motion-ready .fade-up.stagger-1 { transition-delay: 60ms; }
  html.motion-ready .fade-up.stagger-2 { transition-delay: 120ms; }
  html.motion-ready .fade-up.stagger-3 { transition-delay: 180ms; }
  html.motion-ready .fade-up.stagger-4 { transition-delay: 240ms; }
  html.motion-ready .fade-up.stagger-5 { transition-delay: 300ms; }
  html.motion-ready .fade-up.stagger-6 { transition-delay: 360ms; }

  .btn:hover {
    transform: translateY(-2px);
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .fade-up,
  .reveal,
  [data-motion] {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }

  .btn:hover,
  .benefit-card:hover,
  .track-card:hover,
  .metric-card:hover,
  .stat-card:hover,
  .logos__item:hover,
  .logos__item:hover .logos__img {
    transform: none !important;
  }

  .logos__track {
    animation: none !important;
  }

  .logos__row {
    overflow-x: auto;
  }

  .faq-icon {
    transition: none !important;
  }
}

/* Featured Crown Card - Scholarship 25M */
.benefit-card:first-child {
  background: linear-gradient(150deg, #ffffff 0%, var(--green-50) 100%);
  border: 1.5px solid var(--green-300);
  box-shadow: 0 8px 24px rgba(3, 50, 42, 0.08);
  position: relative;
}

.benefit-card:first-child:hover {
  border-color: var(--green-400);
}

/* Timeline Tabs Stepper */

/* FAQ Instant Search */
.faq-search-wrap {
  position: relative;
  max-width: 440px;
  margin: var(--s-16) 0 var(--s-28);
}

.faq-search-icon {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--green-600);
  pointer-events: none;
}

.faq-search-input {
  width: 100%;
  padding: 0.65rem 1rem 0.65rem 2.6rem;
  font-family: var(--font-sans);
  font-size: var(--text-s);
  background: var(--white);
  border: 1.5px solid var(--gray-200);
  border-radius: var(--radius-btn);
  color: var(--gray-900);
  transition: all 0.2s var(--ease);
}

.faq-search-input:focus {
  outline: none;
  border-color: var(--green-400);
  box-shadow: 0 0 0 3px rgba(55, 168, 138, 0.15);
}

.faq-item.is--hidden {
  display: none !important;
}

.faq-item.is--highlight {
  border-color: var(--green-400);
  box-shadow: 0 4px 16px rgba(8, 144, 108, 0.08);
}

/* Form Meta & Character Counters */
.form-meta-row {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--s-16);
  margin-top: var(--s-4);
}

.char-counter {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--gray-500);
  white-space: nowrap;
}

/* Confetti Celebration Canvas */
#confetti-canvas {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 99999;
}

/* 15. RESPONSIVE BREAKPOINTS (3 mốc: desktop >= 1280px, tablet 768-1279px, mobile < 768px) */
@media (max-width: 1279px) {
  :root {
    --title-xl: 3.5rem;
    --title-l: 2.75rem;
    --pad-x: 2rem;
  }

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

  .benefits-grid,
  .tracks-grid,
  .capabilities-grid {
    gap: var(--s-20);
  }
}


@media (max-width: 767px) {
  :root {
    --title-xl: 2.5rem;  /* 40px <= 40px theo E2 */
    --title-l: 2rem;     /* 32px */
    --title-m: 1.75rem;
    --pad-x: 1.5rem;     /* 24px */
    --s-120: 4rem;
    --s-100: 3.5rem;
    --s-80: 3rem;
  }

  .header-brand .logo-tagline {
    display: none;
  }

  .hero-metrics {
    grid-template-columns: 1fr; /* Lưới 3 cột -> 1 cột theo E2 */
  }

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

  .tracks-grid {
    grid-template-columns: 1fr; /* Lưới 2x2 -> 1 cột theo E2 */
  }

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

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

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

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

  .timeline-card {
    padding: var(--s-24);
  }

  .form-wrapper {
    padding: var(--s-24);
  }

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

  .table-wrapper {
    margin-left: calc(-1 * var(--pad-x));
    margin-right: calc(-1 * var(--pad-x));
    border-radius: 0;
    border-left: none;
    border-right: none;
  }

  .schedule-table th,
  .schedule-table td {
    padding: var(--s-12) var(--s-16);
  }

  .journey-card {
    padding: var(--s-24) var(--s-18);
  }

  .round-question {
    font-size: 1.125rem;
  }

  .logos__item {
    width: 136px;
    height: 60px;
    padding: 6px 10px;
    margin-right: var(--s-12);
  }

  .logos__img {
    max-width: 100px;
    max-height: 34px;
  }

  .footer-brand-wrap {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--s-12);
  }
}