/* ═══════════════════════════════════════════════════════════════
   OmniChat Design System
   Aesthetic: Modern SaaS Vietnam — sạch sẽ, tin tưởng, năng động
   Palette: Deep Navy + Electric Indigo + Warm Accent
   ═══════════════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Syne:wght@400;500;600;700;800&family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,400;0,9..40,500;0,9..40,600;1,9..40,300&display=swap');

:root {
  /* Palette */
  --navy:      #0a0e1a;
  --navy-mid:  #111827;
  --navy-soft: #1a2235;
  --indigo:    #4f6ef7;
  --indigo-lt: #7b95ff;
  --indigo-dk: #3451d1;
  --teal:      #06c4aa;
  --teal-lt:   #3dffd8;
  --amber:     #f5a623;
  --rose:      #f75469;
  --white:     #ffffff;
  --off-white: #f4f6fc;
  --gray-100:  #eef1f8;
  --gray-200:  #dde3f0;
  --gray-400:  #8896b3;
  --gray-600:  #4d5e80;

  /* Typography */
  --font-display: 'Syne', sans-serif;
  --font-body:    'DM Sans', sans-serif;

  /* Spacing */
  --section-y: 100px;
  --container: 1200px;
  --radius:    16px;
  --radius-sm: 8px;
  --radius-lg: 24px;

  /* Shadows */
  --shadow-card:  0 4px 32px rgba(10,14,26,.12), 0 1px 4px rgba(10,14,26,.08);
  --shadow-float: 0 20px 60px rgba(79,110,247,.18), 0 4px 16px rgba(10,14,26,.12);
  --shadow-glow:  0 0 40px rgba(79,110,247,.35);
}

/* ── Reset ─────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--navy);
  background: var(--white);
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* ── Container ──────────────────────────────────────────────── */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}
.section { padding: var(--section-y) 0; }

/* ── Typography ─────────────────────────────────────────────── */
h1,h2,h3,h4,h5,h6 {
  font-family: var(--font-display);
  line-height: 1.15;
  font-weight: 700;
  letter-spacing: -.02em;
}
.display-1 { font-size: clamp(3rem, 6vw, 5.5rem); font-weight: 800; letter-spacing: -.04em; }
.display-2 { font-size: clamp(2.2rem, 4vw, 3.5rem); font-weight: 800; letter-spacing: -.03em; }
.h2        { font-size: clamp(1.8rem, 3vw, 2.5rem); font-weight: 700; }
.h3        { font-size: clamp(1.2rem, 2vw, 1.5rem); font-weight: 600; }
.lead      { font-size: clamp(1rem, 1.5vw, 1.2rem); line-height: 1.7; color: var(--gray-600); }
.eyebrow   {
  font-family: var(--font-display);
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--indigo);
}

/* ── Buttons ────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 100px;
  font-family: var(--font-display);
  font-size: .9rem;
  font-weight: 600;
  transition: all .25s ease;
  white-space: nowrap;
}
.btn-primary {
  background: var(--indigo);
  color: var(--white);
  box-shadow: 0 4px 20px rgba(79,110,247,.4);
}
.btn-primary:hover {
  background: var(--indigo-dk);
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(79,110,247,.5);
}
.btn-secondary {
  background: var(--white);
  color: var(--navy);
  border: 1.5px solid var(--gray-200);
}
.btn-secondary:hover {
  border-color: var(--indigo);
  color: var(--indigo);
  transform: translateY(-2px);
}
.btn-outline-white {
  background: transparent;
  color: var(--white);
  border: 1.5px solid rgba(255,255,255,.4);
}
.btn-outline-white:hover {
  background: rgba(255,255,255,.1);
  border-color: rgba(255,255,255,.7);
}
.btn-lg { padding: 16px 36px; font-size: 1rem; }
.btn-sm { padding: 10px 20px; font-size: .82rem; }

/* ── Navbar ─────────────────────────────────────────────────── */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 0;
  transition: background .3s, box-shadow .3s;
}
.navbar.scrolled {
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(20px);
  box-shadow: 0 1px 0 var(--gray-200);
}
.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}
.navbar-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--navy);
}
.navbar-logo .logo-icon {
  width: 36px; height: 36px;
  background: var(--indigo);
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  color: white;
  font-size: 1.1rem;
}
.navbar-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
}
.navbar-nav a {
  padding: 8px 14px;
  border-radius: 8px;
  font-size: .9rem;
  font-weight: 500;
  color: var(--gray-600);
  transition: all .2s;
}
.navbar-nav a:hover, .navbar-nav a.active {
  color: var(--indigo);
  background: rgba(79,110,247,.07);
}
.navbar-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}
.navbar-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 6px;
}
.navbar-hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--navy);
  border-radius: 2px;
  transition: all .3s;
}

/* ── Footer ─────────────────────────────────────────────────── */
.footer {
  background: var(--navy);
  color: rgba(255,255,255,.7);
  padding: 72px 0 40px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid rgba(255,255,255,.08);
}
.footer-brand .logo { color: white; margin-bottom: 16px; }
.footer-brand p { font-size: .9rem; line-height: 1.8; color: rgba(255,255,255,.5); max-width: 280px; }
.footer-socials { display: flex; gap: 10px; margin-top: 24px; }
.footer-socials a {
  width: 36px; height: 36px;
  border-radius: 8px;
  background: rgba(255,255,255,.07);
  display: flex; align-items: center; justify-content: center;
  font-size: .85rem;
  transition: all .2s;
}
.footer-socials a:hover { background: var(--indigo); color: white; }
.footer-col h5 {
  font-family: var(--font-display);
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: rgba(255,255,255,.4);
  margin-bottom: 20px;
}
.footer-col ul { list-style: none; }
.footer-col ul li { margin-bottom: 10px; }
.footer-col ul li a {
  font-size: .9rem;
  color: rgba(255,255,255,.6);
  transition: color .2s;
}
.footer-col ul li a:hover { color: white; }
.footer-bottom {
  padding-top: 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: .82rem;
  color: rgba(255,255,255,.35);
  flex-wrap: wrap;
  gap: 12px;
}

/* ── Cards ──────────────────────────────────────────────────── */
.card {
  background: var(--white);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow-card);
  transition: transform .25s, box-shadow .25s;
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-float);
}

/* ── Channel badges ─────────────────────────────────────────── */
.badge-channel {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border-radius: 100px;
  font-size: .78rem;
  font-weight: 600;
}
.badge-fb    { background: #e8eeff; color: #1877f2; }
.badge-zalo  { background: #e6f4ff; color: #0068ff; }
.badge-ig    { background: #fde8f8; color: #e1306c; }
.badge-tt    { background: #ffe8ed; color: #fe2c55; }
.badge-wa    { background: #e6f9f0; color: #25d366; }

/* ── Section decorations ────────────────────────────────────── */
.section-bg-soft { background: var(--off-white); }
.section-bg-dark { background: var(--navy); color: var(--white); }
.section-header { text-align: center; max-width: 680px; margin: 0 auto 64px; }
.section-header .lead { margin-top: 16px; }

/* ── Gradient text ──────────────────────────────────────────── */
.gradient-text {
  background: linear-gradient(135deg, var(--indigo) 0%, var(--teal) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ── Tag ────────────────────────────────────────────────────── */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: rgba(79,110,247,.08);
  border: 1px solid rgba(79,110,247,.2);
  border-radius: 100px;
  font-size: .8rem;
  font-weight: 600;
  color: var(--indigo);
  margin-bottom: 20px;
}

/* ── Divider ────────────────────────────────────────────────── */
.divider-dot { display: inline-block; width: 4px; height: 4px; border-radius: 50%; background: var(--gray-400); vertical-align: middle; margin: 0 8px; }

/* ── Responsive ─────────────────────────────────────────────── */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
  :root { --section-y: 64px; }
  .navbar-nav, .navbar-actions .btn { display: none; }
  .navbar-hamburger { display: flex; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .footer-bottom { flex-direction: column; text-align: center; }
}