@import url('https://fonts.googleapis.com/css2?family=Be+Vietnam+Pro:wght@400;500;600;700;800&display=swap');

:root {
  --bg: #F8FAFC;
  --surface: #FFFFFF;
  --surface-muted: #F1F5F9;
  --text: #0F172A;
  --text-muted: #64748B;
  --accent: #1D4ED8;
  --accent-hover: #1E40AF;
  --accent-light: #DBEAFE;
  --accent-dark: #1E3A8A;
  --success: #059669;
  --success-light: #D1FAE5;
  --danger: #DC2626;
  --danger-light: #FEE2E2;
  --border: #E2E8F0;
  --shadow: 0 1px 2px rgba(15, 23, 42, 0.04), 0 8px 24px rgba(15, 23, 42, 0.06);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0B1220;
    --surface: #121A2C;
    --surface-muted: #0F1729;
    --text: #F1F5F9;
    --text-muted: #94A3B8;
    --accent: #60A5FA;
    --accent-hover: #93C5FD;
    --accent-light: #1E3A5F;
    --accent-dark: #BFDBFE;
    --success: #34D399;
    --success-light: #0F3D2E;
    --danger: #F87171;
    --danger-light: #3F1D1D;
    --border: #24304A;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.2), 0 8px 24px rgba(0, 0, 0, 0.35);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Be Vietnam Pro", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

img, svg { max-width: 100%; }

h1, h2, h3 {
  font-family: "Be Vietnam Pro", sans-serif;
  font-weight: 800;
  line-height: 1.2;
  text-wrap: balance;
  margin: 0 0 0.5em;
}

p { margin: 0 0 1em; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 clamp(20px, 5vw, 48px);
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-top: 14px;
  padding-bottom: 14px;
}

.wordmark {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--text);
}

.wordmark:hover { text-decoration: none; }

.wordmark .logo-mark {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  background: var(--accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1rem;
  flex-shrink: 0;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(14px, 3vw, 28px);
  font-weight: 600;
  font-size: 0.95rem;
}

.nav-links a { color: var(--text-muted); }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--accent); text-decoration: none; }

.nav-toggle { display: none; }

@media (max-width: 620px) {
  .nav-links {
    position: fixed;
    inset: 62px 0 auto 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    align-items: flex-start;
    padding: 16px clamp(20px, 5vw, 48px) 20px;
    gap: 14px;
    transform: translateY(-8px);
    opacity: 0;
    pointer-events: none;
    transition: 0.15s ease;
  }
  .nav-toggle:checked ~ .nav-links {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .nav-burger {
    display: flex;
    width: 38px;
    height: 38px;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    border: 1px solid var(--border);
    cursor: pointer;
  }
}

.nav-burger { display: none; }
@media (max-width: 620px) { .nav-burger { display: flex; } }

/* Hero */
.hero {
  padding: clamp(48px, 9vw, 96px) 0 clamp(32px, 6vw, 64px);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: clamp(32px, 5vw, 64px);
  align-items: center;
}

@media (max-width: 860px) {
  .hero-grid { grid-template-columns: 1fr; }
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent-light);
  color: var(--accent-dark);
  font-weight: 700;
  font-size: 0.85rem;
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 18px;
}

.hero h1 {
  font-size: clamp(2rem, 4.2vw, 3.1rem);
}

.hero .lede {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 46ch;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 28px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 0.98rem;
  padding: 13px 24px;
  border-radius: 12px;
  border: 1px solid transparent;
  cursor: pointer;
}

.btn:hover { text-decoration: none; }

.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-hover); }

.btn-ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

.hero-art {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: var(--shadow);
  padding: clamp(20px, 3vw, 32px);
}

/* Differentiator grid */
.diff-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-top: 20px;
}

@media (max-width: 700px) {
  .diff-grid { grid-template-columns: 1fr; }
}

.diff-card, .feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
}

.icon-badge {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--accent-light);
  color: var(--accent-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
}

.icon-badge svg { width: 26px; height: 26px; }

.diff-card h3, .feature-card h3 {
  font-size: 1.05rem;
  margin-bottom: 6px;
}

.diff-card p, .feature-card p {
  color: var(--text-muted);
  font-size: 0.97rem;
  margin-bottom: 0;
}

/* Section */
section { padding: clamp(40px, 7vw, 80px) 0; }

.section-head { max-width: 60ch; margin-bottom: 36px; }
.section-head h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); }
.section-head p { color: var(--text-muted); font-size: 1.05rem; }

.pill-quote {
  display: inline-block;
  margin-top: 8px;
  padding: 16px 22px;
  border-radius: 14px;
  background: var(--accent-dark);
  color: #EFF6FF;
  font-weight: 700;
  font-size: 1.05rem;
}

/* Feature list */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

@media (max-width: 900px) { .feature-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 600px) { .feature-grid { grid-template-columns: 1fr; } }

/* Comparison strip */
.compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
@media (max-width: 700px) { .compare { grid-template-columns: 1fr; } }

.compare .col {
  border-radius: 16px;
  padding: 24px;
  border: 1px solid var(--border);
}
.compare .col.bad { background: var(--danger-light); }
.compare .col.good { background: var(--success-light); }
.compare h3 { font-size: 1rem; }
.compare ul { margin: 0; padding-left: 20px; }
.compare li { margin-bottom: 8px; color: var(--text); }

/* CTA band */
.cta-band {
  background: var(--accent);
  color: #fff;
  border-radius: 24px;
  padding: clamp(32px, 6vw, 56px);
  text-align: center;
}
.cta-band h2 { color: #fff; }
.cta-band p { color: #DBEAFE; }
.cta-band .btn-primary { background: #fff; color: var(--accent); }
.cta-band .btn-primary:hover { background: #EFF6FF; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 40px 0;
  margin-top: 40px;
}
.footer-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: space-between;
  align-items: flex-start;
}
.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  font-weight: 600;
  font-size: 0.92rem;
}
.footer-links a { color: var(--text-muted); }
.footer-note { color: var(--text-muted); font-size: 0.88rem; margin-top: 12px; }

/* FAQ */
.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 20px 0;
}
.faq-item summary {
  cursor: pointer;
  font-weight: 700;
  font-size: 1.05rem;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  font-size: 1.4rem;
  color: var(--accent);
  flex-shrink: 0;
  transition: transform 0.15s ease;
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item p { color: var(--text-muted); margin-top: 12px; margin-bottom: 0; }

/* Legal page (privacy policy) */
.legal { max-width: 720px; }
.legal h2 { font-size: 1.2rem; margin-top: 2rem; }
.legal .updated { color: var(--text-muted); font-size: 0.9rem; }
.legal ul { padding-left: 1.25rem; }

/* Feature detail rows (tinh-nang.html) */
@media (max-width: 780px) {
  .feature-row {
    grid-template-columns: 1fr !important;
  }
  .feature-row svg {
    order: 0 !important;
  }
}

/* Number badges (features page steps) */
.step-badge {
  width: 30px;
  height: 30px;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  font-weight: 800;
  font-size: 0.85rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-right: 10px;
}