:root {
  --brand-bg: #5b21b6;
  --bg: #f8f5ff;
  --bg-accent: #ede9fe;
  --surface: #ffffff;
  --surface-muted: #faf8ff;
  --text: #1a0f2e;
  --text-muted: #6b5c8a;
  --primary: #7c3aed;
  --primary-strong: #5b21b6;
  --accent: #ec4899;
  --border: #e4d5f5;
  --shadow: 0 18px 45px rgba(91, 33, 182, 0.08);
  --radius: 18px;
  --radius-sm: 12px;
  --container: 1120px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: "Avenir Next", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background:
    radial-gradient(1200px 600px at 20% -10%, rgba(124, 58, 237, 0.14), transparent 50%),
    radial-gradient(900px 480px at 100% 0%, rgba(236, 72, 153, 0.12), transparent 60%),
    var(--bg);
  line-height: 1.6;
}

a {
  color: inherit;
}

.container {
  width: min(var(--container), 92vw);
  margin: 0 auto;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(14px);
  background: rgba(255, 255, 255, 0.88);
  border-bottom: 1px solid rgba(220, 230, 245, 0.85);
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  letter-spacing: 0.2px;
}

.brand-icon {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  object-fit: cover;
}

.lang-toggle {
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  border-radius: 999px;
  min-width: 76px;
  height: 40px;
  font-weight: 700;
  cursor: pointer;
  flex-shrink: 0;
}

.promo-marquee {
  flex: 1;
  min-width: 180px;
  height: 42px;
  border: 1px solid rgba(236, 72, 153, 0.85);
  border-radius: 999px;
  overflow: hidden;
  background: rgba(5, 22, 45, 0.5);
  display: flex;
  align-items: center;
}

.promo-track {
  display: inline-flex;
  align-items: center;
  gap: 28px;
  white-space: nowrap;
  color: #ecf4ff;
  font-weight: 700;
  font-size: 0.93rem;
  padding-left: 18px;
  animation: promo-scroll 38s linear infinite;
}

.promo-track span::after {
  content: "•";
  margin-left: 28px;
  color: #7ec4ff;
}

@keyframes promo-scroll {
  from {
    transform: translateX(0);
  }

  to {
    transform: translateX(-50%);
  }
}

@media (prefers-reduced-motion: reduce) {
  .promo-track {
    animation: none;
  }
}

.hero {
  padding: 72px 0 52px;
  background: linear-gradient(135deg, #5b21b6 0%, #7c3aed 55%, #ec4899 100%);
  color: #fff;
  box-shadow: inset 0 -1px 0 rgba(255, 255, 255, 0.2);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 36px;
  align-items: center;
}

.hero h1 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  line-height: 1.12;
  margin: 0 0 16px;
  letter-spacing: -0.4px;
}

.hero .subtitle {
  margin: 0 0 20px;
  color: rgba(255, 255, 255, 0.9);
  font-size: 1.08rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 0 0 20px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  text-decoration: none;
  border-radius: 12px;
  padding: 12px 18px;
  font-weight: 700;
  border: 1px solid transparent;
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  box-shadow: 0 10px 26px rgba(10, 103, 216, 0.22);
}

.btn-secondary {
  color: #fff;
  background: rgba(255, 255, 255, 0.14);
  border-color: rgba(255, 255, 255, 0.5);
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.42);
  background: rgba(255, 255, 255, 0.12);
  font-size: 0.92rem;
  color: rgba(255, 255, 255, 0.96);
}

.device-card {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 24px;
  box-shadow: 0 16px 38px rgba(0, 27, 68, 0.24);
  padding: 20px;
}

.device-shot {
  width: 100%;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.94);
  color: #143053;
  padding: 28px 20px;
}

.device-shot h3 {
  margin: 0 0 12px;
  font-size: 1.2rem;
}

.device-shot ul {
  margin: 0;
  padding-left: 18px;
}

section {
  padding: 20px 0 8px;
}

.section-heading {
  margin: 0 0 18px;
}

.section-heading h2 {
  margin: 0 0 6px;
  font-size: clamp(1.35rem, 2.8vw, 2rem);
}

.section-heading p {
  margin: 0;
  color: var(--text-muted);
}

.grid {
  display: grid;
  gap: 14px;
}

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.learn-showcase {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.learn-mode-card {
  background: linear-gradient(180deg, #ffffff 0%, #f3f8ff 100%);
  border: 1px solid var(--border);
  border-radius: 18px;
  box-shadow: var(--shadow);
  padding: 18px;
  overflow: hidden;
}

.learn-mode-card h3 {
  margin: 0 0 8px;
  color: #7c3aed;
  letter-spacing: 0.5px;
  font-size: clamp(1.1rem, 2.2vw, 1.55rem);
}

.learn-mode-card p {
  margin: 0 0 14px;
  color: #4a6385;
}

.learn-mode-image {
  width: 100%;
  max-width: 360px;
  display: block;
  margin: 0 auto;
  background: transparent;
  padding: 0;
  border-radius: 22px;
  box-shadow: none;
  border: 0;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
}

.card h3 {
  margin: 0 0 10px;
}

.card p {
  margin: 0;
  color: var(--text-muted);
}

.feature-list {
  margin: 12px 0 0;
  padding-left: 18px;
  color: var(--text-muted);
}

.feature-list li + li {
  margin-top: 6px;
}

.tag {
  display: inline-block;
  margin-bottom: 8px;
  font-size: 0.8rem;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--primary-strong);
  font-weight: 700;
}

.quote {
  font-style: italic;
  margin: 0 0 8px;
}

.quote-author {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.92rem;
}

.reviews-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.review-card h3 {
  margin: 0 0 4px;
  font-size: 1rem;
}

.review-stars {
  margin: 0 0 8px;
  color: #f59e0b;
  letter-spacing: 1px;
  font-size: 0.95rem;
}

.review-text {
  font-size: 0.95rem;
  line-height: 1.5;
}

.faq details {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px 14px;
}

.faq details + details {
  margin-top: 10px;
}

.faq summary {
  cursor: pointer;
  font-weight: 700;
}

.faq p {
  margin: 10px 0 2px;
  color: var(--text-muted);
}

.support {
  margin: 30px auto 44px;
  background: linear-gradient(140deg, rgba(124, 58, 237, 0.11), rgba(236, 72, 153, 0.08));
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 24px;
}

.store-list {
  display: grid;
  gap: 10px;
}

.store-item {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 8px;
  padding: 10px 0;
  border-bottom: 1px dashed var(--border);
}

.store-item:last-child {
  border-bottom: 0;
}

.store-label {
  color: var(--text-muted);
  font-weight: 600;
}

.support h2 {
  margin: 0 0 8px;
}

.support p {
  margin: 0 0 14px;
  color: var(--text-muted);
}

footer {
  border-top: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.82);
  padding: 18px 0 24px;
}

.footer-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.footer-links a {
  color: var(--primary-strong);
  text-decoration: none;
  font-weight: 600;
}

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

.footer-note {
  color: var(--text-muted);
  font-size: 0.92rem;
}

.lang-section[data-lang-section="en"] {
  display: none;
}

html[lang="en"] .lang-section[data-lang-section="vi"] {
  display: none;
}

html[lang="en"] .lang-section[data-lang-section="en"] {
  display: block;
}

html[lang="en"] .lang-section[data-lang-section="en"].footer-inline {
  display: flex;
}

@media (max-width: 980px) {
  .hero-grid,
  .grid-3,
  .grid-2,
  .reviews-grid,
  .learn-showcase {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 38px;
  }

  .promo-marquee {
    display: none;
  }

  .store-item {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .card,
  .support,
  .device-card {
    padding: 18px;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0c0714;
    --bg-accent: #11082a;
    --surface: #150d28;
    --surface-muted: #14092a;
    --text: #f0eafb;
    --text-muted: #c4aee8;
    --primary: #a78bfa;
    --primary-strong: #c4b5fd;
    --accent: #f472b6;
    --border: #2d1a5c;
    --shadow: 0 18px 45px rgba(0, 0, 0, 0.34);
  }

  .topbar {
    background: rgba(10, 5, 22, 0.85);
  }

  .promo-marquee {
    background: rgba(25, 10, 55, 0.72);
    border-color: rgba(167, 139, 250, 0.55);
  }

  .learn-mode-card {
    background: linear-gradient(180deg, #1a0d38 0%, #140a2e 100%);
    border-color: #3d1f7a;
  }

  .learn-mode-card h3 {
    color: #c4b5fd;
  }

  .learn-mode-card p {
    color: #e0d5f8;
  }

  .learn-mode-image {
    background: transparent;
    border: 0;
    box-shadow: none;
  }

  footer {
    background: rgba(8, 4, 18, 0.82);
  }
}