:root {
  --primary: #0B63E5;
  --primary-hover: #0852C4;
  --ink: #101828;
  --muted: #667085;
  --line: #E4E7EC;
  --page-bg: #F6F8FC;
  --card-bg: #FFFFFF;
  --online: #17B26A;
  --offline: #F04438;
  --amber: #F5A623;
  --radius: 16px;
  --font-display: 'Space Grotesk', ui-sans-serif, system-ui, sans-serif;
  --font-body: 'Inter', ui-sans-serif, system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background: var(--page-bg);
  color: var(--ink);
  font-family: var(--font-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  padding-bottom: 60px;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
ul { list-style: none; }
img, svg { display: block; max-width: 100%; }

/* Container Widths */
.wrap-nav { max-width: 1180px; margin: 0 auto; padding: 0 24px; }
.wrap { max-width: 1180px; margin: 0 auto; padding: 0 24px; }
.wrap-narrow { max-width: 900px; margin: 0 auto; padding: 0 24px; }
.wrap-compact { max-width: 800px; margin: 0 auto; padding: 0 24px; }

/* Eyebrow badge */
.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--primary);
  display: inline-flex; align-items: center; gap: 8px;
  margin-bottom: 12px;
}
.eyebrow::before {
  content: "";
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--primary);
}

h1, h2, h3 { font-family: var(--font-display); font-weight: 700; letter-spacing: -.02em; line-height: 1.25; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-family: var(--font-body); font-weight: 700; font-size: 15px;
  padding: 14px 28px; border-radius: 12px;
  cursor: pointer; border: 1.5px solid transparent;
  transition: all .2s ease;
  white-space: nowrap;
  text-decoration: none;
}
.btn:active { transform: scale(.96); }
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: var(--primary-hover); box-shadow: 0 8px 20px rgba(11,99,229,0.25); text-decoration: none; }
.btn-ghost { border-color: var(--line); color: var(--muted); background: white; }
.btn-ghost:hover { border-color: var(--primary); color: var(--primary); text-decoration: none; }

/* Hero Section */
.hero { padding: 80px 0 60px; }
.hero-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 60px; align-items: center; }
.hero h1 { font-size: clamp(36px, 5vw, 58px); line-height: 1.1; margin-bottom: 24px; color: var(--ink); }
.hero h1 .accent { color: var(--primary); }
.hero p.lede { font-size: 18px; color: var(--muted); max-width: 520px; margin-bottom: 32px; }
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 40px; }

/* Top-down Car Viz */
.viz-panel {
  position: relative;
  background: #eef2f7;
  border-radius: 24px;
  padding: 30px;
  border: 1px solid var(--line);
  box-shadow: 0 20px 40px rgba(0,0,0,0.05);
  overflow: hidden;
}
.viz-map {
  width: 100%; aspect-ratio: 1/1;
  background: white; border-radius: 16px;
  background-image:
    linear-gradient(#f1f4f9 1.5px, transparent 1.5px),
    linear-gradient(90deg, #f1f4f9 1.5px, transparent 1.5px);
  background-size: 40px 40px;
  position: relative;
  display: flex; align-items: center; justify-content: center;
}
.car-top-down {
  width: 120px !important;
  max-width: 120px !important;
  height: auto !important;
  filter: drop-shadow(0 10px 15px rgba(0,0,0,0.15));
  z-index: 2;
  transform: rotate(45deg);
}
.track-line {
  position: absolute;
  width: 200%; height: 200%;
  stroke: var(--primary);
  stroke-width: 6;
  stroke-linecap: round;
  fill: none;
  opacity: 0.15;
  z-index: 1;
}

/* Sections */
section { padding: 80px 0; }
.section-head { max-width: 700px; margin-bottom: 40px; }
.section-head h2 { font-size: 36px; color: var(--ink); margin-bottom: 16px; }
.section-head p { color: var(--muted); font-size: 17px; }

/* Subjects Grid */
.subjects { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.subject-card {
  background: white; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 32px; transition: all .3s ease;
}
.subject-card:hover { border-color: var(--primary); transform: translateY(-5px); box-shadow: 0 15px 30px rgba(0,0,0,0.04); }
.subject-icon {
  width: 52px; height: 52px; border-radius: 12px;
  background: #f0f7ff; color: var(--primary);
  display: flex; align-items: center; justify-content: center; margin-bottom: 24px;
}
.subject-card h3 { font-size: 20px; margin-bottom: 12px; color: var(--ink); }
.subject-card p { color: var(--muted); font-size: 15px; margin-bottom: 20px; }
.subject-specs { display: flex; flex-direction: column; gap: 10px; }
.subject-specs li { font-size: 14px; font-weight: 600; color: var(--primary); display: flex; gap: 8px; }
.subject-specs li::before { content: "•"; color: var(--muted); }

/* Waypoints / Cách hoạt động */
.waypoints { position: relative; padding-left: 8px; }
.waypoints::before {
  content: ""; position: absolute; left: 23px; top: 10px; bottom: 10px; width: 2px;
  background: var(--line);
}
.waypoint { display: grid; grid-template-columns: 48px 1fr; gap: 22px; padding-bottom: 40px; position: relative; }
.wp-node {
  width: 48px; height: 48px; border-radius: 50%;
  background: white; border: 2px solid var(--primary);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-mono); font-size: 14px; font-weight: 800; color: var(--primary);
  z-index: 1;
}
.waypoint h3 { font-size: 18px; margin-bottom: 6px; color: var(--ink); }
.waypoint p { color: var(--muted); font-size: 15px; }

/* Shared Card Layout */
.main-card {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 40px;
  margin-top: 40px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.03);
}

/* Alert Boxes */
.alert-box {
  background: #EFF8FF;
  border: 1px solid #B2DDFF;
  border-radius: 10px;
  padding: 16px;
  margin: 12px 0;
  color: #175CD3;
  font-size: 14px;
}
.alert-box.warning {
  background: #FFFAEB;
  border-color: #FEDF89;
  color: #B54708;
}
.alert-box.important {
  background: #FEF3F2;
  border-color: #FECDCA;
  color: #B42318;
}
.alert-box h4 {
  font-weight: 700;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

/* Download Center Cards & Store Buttons */
.download-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
  margin-top: 32px;
}
.download-card {
  background: white;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 36px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all .25s ease;
}
.download-card:hover {
  border-color: var(--primary);
  box-shadow: 0 12px 28px rgba(11, 99, 229, 0.08);
  transform: translateY(-3px);
}
.download-card-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--primary);
  background: #EFF8FF;
  padding: 6px 14px;
  border-radius: 20px;
  width: fit-content;
  margin-bottom: 16px;
}
.download-card h3 {
  font-size: 22px;
  color: var(--ink);
  margin-bottom: 10px;
}
.download-card p {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.6;
  margin-bottom: 28px;
}
.download-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.store-btn {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 13px 20px;
  border-radius: 12px;
  background: var(--ink);
  color: white;
  font-family: var(--font-body);
  text-decoration: none;
  transition: all .25s ease;
  flex: 1;
  min-width: 170px;
  justify-content: center;
}
.store-btn:hover {
  text-decoration: none;
  transform: translateY(-2px);
}
.store-btn.btn-playstore {
  background: #01875F;
  color: white;
}
.store-btn.btn-playstore:hover {
  background: #016E4F;
  box-shadow: 0 8px 20px rgba(1, 135, 95, 0.3);
}
.store-btn.btn-appstore {
  background: #0071E3;
  color: white;
}
.store-btn.btn-appstore:hover {
  background: #0058B3;
  box-shadow: 0 8px 20px rgba(0, 113, 227, 0.3);
}
.store-btn.btn-apk {
  background: #0B63E5;
  color: white;
  border: none;
}
.store-btn.btn-apk:hover {
  background: #0852C4;
  box-shadow: 0 8px 20px rgba(11, 99, 229, 0.3);
}
.store-btn svg {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
}
.store-btn-text {
  display: flex;
  flex-direction: column;
  text-align: left;
  line-height: 1.25;
}
.store-btn-text span.small {
  font-size: 11px;
  opacity: 0.85;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: .03em;
}
.store-btn-text span.bold {
  font-size: 15px;
  font-weight: 700;
}

/* Quick Setup Guide (3 Steps) */
.quick-guide {
  margin-top: 52px;
  padding-top: 44px;
  border-top: 1px solid var(--line);
}
.quick-guide-head {
  text-align: center;
  max-width: 640px;
  margin: 0 auto 36px;
}
.quick-guide-head h3 {
  font-size: 26px;
  color: var(--ink);
  margin-bottom: 8px;
}
.quick-guide-head p {
  color: var(--muted);
  font-size: 15px;
}
.guide-steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}
.guide-step-card {
  background: #F8FAFC;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all .25s ease;
}
.guide-step-card:hover {
  border-color: var(--primary);
  box-shadow: 0 8px 24px rgba(11, 99, 229, 0.08);
  transform: translateY(-3px);
}
.guide-step-number {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: 15px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}
.guide-step-content h4 {
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 8px;
}
.guide-step-content p {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.6;
  margin-bottom: 20px;
}
.guide-step-media {
  margin-top: auto;
  background: white;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 180px;
  overflow: hidden;
}
.guide-step-media img {
  max-height: 160px;
  width: auto;
  object-fit: contain;
  border-radius: 8px;
}

/* Data Security Section */
.security-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
  margin-top: 36px;
}
.security-card {
  background: white;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 32px;
  display: flex;
  gap: 20px;
  align-items: flex-start;
  transition: all .25s ease;
}
.security-card:hover {
  border-color: var(--primary);
  box-shadow: 0 8px 24px rgba(11, 99, 229, 0.08);
  transform: translateY(-3px);
}
.security-icon {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  background: #EFF8FF;
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.security-icon svg {
  width: 26px;
  height: 26px;
}
.security-body h3 {
  font-size: 19px;
  color: var(--ink);
  margin-bottom: 8px;
}
.security-body p {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.6;
}

/* Free Usage Section Cards */
.free-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin-top: 36px;
}
.free-card {
  background: white;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 32px;
  transition: all .25s ease;
  display: flex;
  flex-direction: column;
}
.free-card:hover {
  border-color: var(--primary);
  box-shadow: 0 12px 28px rgba(11, 99, 229, 0.08);
  transform: translateY(-4px);
}
.free-card-icon {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  background: #EFF8FF;
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}
.free-card-icon svg {
  width: 26px;
  height: 26px;
}
.free-card h3 {
  font-size: 20px;
  color: var(--ink);
  margin-bottom: 12px;
}
.free-card p {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.6;
}

/* Feature Showcase Section */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin-top: 36px;
}
.feature-card {
  background: white;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 32px;
  transition: all .25s ease;
  position: relative;
  display: flex;
  flex-direction: column;
}
.feature-card:hover {
  border-color: var(--primary);
  box-shadow: 0 12px 28px rgba(11, 99, 229, 0.08);
  transform: translateY(-4px);
}
.feature-card.highlight {
  grid-column: span 2;
  background: linear-gradient(135deg, #FFFFFF 0%, #F0F7FF 100%);
  border: 1.5px solid #B2CCF8;
}
.feature-icon {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  background: #EFF8FF;
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}
.feature-icon svg {
  width: 26px;
  height: 26px;
}
.feature-badge {
  display: inline-flex;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--primary);
  background: #E0EAFF;
  padding: 4px 10px;
  border-radius: 12px;
  width: fit-content;
  margin-bottom: 12px;
}
.feature-card h3 {
  font-size: 20px;
  color: var(--ink);
  margin-bottom: 10px;
}
.feature-card p {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.65;
}

/* FAQ Accordion Section */
.faq-section {
  margin-top: 36px;
}
.faq-group {
  margin-top: 28px;
}
.faq-group-title {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.faq-group-title svg {
  color: var(--primary);
}
.faq-card {
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: 12px;
  margin-bottom: 12px;
  overflow: hidden;
  transition: border-color .2s, box-shadow .2s;
}
.faq-card:hover {
  border-color: #B2CCF8;
}
.faq-card.open {
  border-color: var(--primary);
  box-shadow: 0 4px 16px rgba(11, 99, 229, 0.06);
}
.faq-header {
  padding: 20px 24px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}
.faq-question {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
  padding-right: 16px;
}
.faq-icon {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
  transition: transform .25s ease;
  color: var(--muted);
}
.faq-card.open .faq-icon {
  transform: rotate(180deg);
  color: var(--primary);
}
.faq-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height .3s ease, padding .3s ease;
  background: #FAFCFF;
  border-top: 0px solid var(--line);
}
.faq-card.open .faq-body {
  max-height: 1200px;
  border-top: 1px solid var(--line);
  padding: 20px 24px;
}
.faq-content {
  color: #344054;
  font-size: 15px;
  line-height: 1.65;
}
.faq-content p {
  margin-bottom: 12px;
}
.faq-content p:last-child {
  margin-bottom: 0;
}
.faq-content ol, .faq-content ul {
  padding-left: 20px;
  margin-bottom: 12px;
}
.faq-content li {
  margin-bottom: 8px;
}

@media (max-width: 900px) {
  .hero-grid, .subjects { grid-template-columns: 1fr; }
  .download-cards { grid-template-columns: 1fr; gap: 24px; }
  .download-card { padding: 28px 20px; }
  .guide-steps-grid { grid-template-columns: 1fr; gap: 20px; }
  .security-grid { grid-template-columns: 1fr; gap: 20px; }
  .free-grid { grid-template-columns: 1fr; gap: 20px; }
  .features-grid { grid-template-columns: 1fr; gap: 20px; }
  .feature-card.highlight { grid-column: span 1; }
}

@media (max-width: 640px) {
  .main-card { padding: 28px 22px; margin-top: 24px; }
  .wrap, .wrap-nav, .wrap-narrow, .wrap-compact { padding: 0 16px; }
  .faq-header { padding: 16px; }
  .faq-card.open .faq-body { padding: 16px; }
}