/* ============================================================
   Ant Messenger — Official Website Stylesheet
   Brand: emerald green / deep pine / off-white
   ============================================================ */

/* ---------- Design Tokens ---------- */
:root {
  --blue-50:  #E8F3FC;
  --blue-100: #C9E5F8;
  --blue-400: #5AA9F0;
  --blue-500: #2E8FE6;
  --blue-600: #1B6FC4;
  --blue-700: #0D3B66;

  --ink-900: #0C2237;
  --ink-800: #123049;
  --ink-700: #1E3D5A;
  --ink-500: #4A6378;
  --ink-400: #6B8299;
  --ink-300: #9AACC0;

  --bg:       #FFFFFF;
  --bg-soft:  #F0F7FC;
  --bg-dark:  #0A1E33;
  --line:     #DCE8F2;

  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;

  --shadow-sm: 0 2px 8px rgba(12, 34, 55, .06);
  --shadow-md: 0 12px 32px rgba(12, 34, 55, .10);
  --shadow-lg: 0 24px 64px rgba(12, 34, 55, .14);

  --max-w: 1200px;
  --font: "Plus Jakarta Sans", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font);
  color: var(--ink-900);
  background: var(--bg);
  line-height: 1.6;
  font-size: 16px;
  letter-spacing: -0.01em;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }
ul { list-style: none; }

/* ---------- Layout ---------- */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}
section { padding: 100px 0; }
.section-head { max-width: 680px; margin: 0 auto 64px; text-align: center; }
.eyebrow {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--blue-600);
  margin-bottom: 16px;
}
h1, h2, h3, h4 { font-weight: 700; line-height: 1.15; letter-spacing: -0.02em; }
h1 { font-size: clamp(40px, 6vw, 68px); }
h2 { font-size: clamp(30px, 4vw, 44px); }
h3 { font-size: 22px; }
.lead {
  font-size: 19px;
  color: var(--ink-500);
  margin-top: 20px;
  line-height: 1.7;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 15px;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
  white-space: nowrap;
}
.btn-primary {
  background: var(--blue-500);
  color: #fff;
  box-shadow: 0 8px 24px rgba(46, 143, 230, .35);
}
.btn-primary:hover { background: var(--blue-600); transform: translateY(-2px); }
.btn-ghost {
  background: transparent;
  color: var(--ink-900);
  border: 1.5px solid var(--line);
}
.btn-ghost:hover { border-color: var(--ink-900); }
.btn-dark {
  background: var(--ink-900);
  color: #fff;
}
.btn-dark:hover { background: #000; transform: translateY(-2px); }

/* ============================================================
   Header
   ============================================================ */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 18px 0;
  transition: background .3s ease, box-shadow .3s ease, padding .3s ease;
}
.site-header.scrolled {
  background: rgba(255,255,255,.9);
  backdrop-filter: saturate(180%) blur(16px);
  box-shadow: 0 1px 0 var(--line);
  padding: 12px 0;
}
.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 20px;
}
.brand img { height: 38px; width: 38px; border-radius: 9px; object-fit: cover; }
.nav-links {
  display: flex;
  gap: 36px;
  font-weight: 500;
  font-size: 15px;
  color: var(--ink-700);
}
.nav-links a { transition: color .2s; }
.nav-links a:hover { color: var(--blue-600); }
.nav-cta { display: flex; align-items: center; gap: 12px; }
.menu-toggle { display: none; flex-direction: column; gap: 5px; padding: 8px; }
.menu-toggle span {
  width: 22px; height: 2px;
  background: var(--ink-900);
  border-radius: 2px;
  transition: .3s;
}

/* ============================================================
   Hero
   ============================================================ */
.hero {
  padding: 180px 0 80px;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(46,143,230,.12), transparent 60%),
    radial-gradient(800px 400px at 10% 10%, rgba(46,143,230,.08), transparent 60%),
    var(--bg);
  text-align: center;
  position: relative;
}
.hero h1 .accent {
  color: var(--blue-600);
  position: relative;
  display: inline-block;
}
.hero .lead { max-width: 620px; margin-left: auto; margin-right: auto; }
.hero-cta {
  margin-top: 36px;
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}
.hero-trust {
  margin-top: 20px;
  font-size: 14px;
  color: var(--ink-400);
}
.hero-visual {
  margin-top: 60px;
  position: relative;
}
.hero-phone {
  max-width: 340px;
  margin: 0 auto;
  filter: drop-shadow(0 30px 60px rgba(10,31,28,.25));
}
.hero-desktop {
  width: 100%;
  max-width: 780px;
  margin: -40px auto 0;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
}

/* ---------- Stats bar ---------- */
.stats {
  background: var(--bg);
  padding: 40px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}
.stat-num {
  font-size: 36px;
  font-weight: 800;
  color: var(--ink-900);
  letter-spacing: -0.02em;
}
.stat-label {
  font-size: 14px;
  color: var(--ink-400);
  margin-top: 4px;
}

/* ============================================================
   Features (alternating rows)
   ============================================================ */
.feature-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
  padding: 60px 0;
}
.feature-row.reverse .feature-media { order: 2; }
.feature-media {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}
.feature-media img { width: 100%; height: auto; }
.feature-text .eyebrow { margin-bottom: 12px; }
.feature-text h2 { margin-bottom: 18px; }
.feature-text p { color: var(--ink-500); font-size: 17px; margin-bottom: 24px; }
.feature-list li {
  display: flex;
  gap: 12px;
  margin-bottom: 14px;
  font-size: 15px;
  color: var(--ink-700);
}
.feature-list .check {
  flex-shrink: 0;
  width: 22px; height: 22px;
  border-radius: 50%;
  background: var(--blue-100);
  color: var(--blue-700);
  display: grid;
  place-items: center;
  font-size: 12px;
  font-weight: 700;
  margin-top: 2px;
}

/* ============================================================
   Apps / Download
   ============================================================ */
.apps {
  background: var(--bg-soft);
}
.apps-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.app-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 32px 24px;
  text-align: center;
  transition: transform .25s ease, box-shadow .25s ease;
}
.app-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}
.app-icon {
  width: 56px; height: 56px;
  margin: 0 auto 18px;
  border-radius: 14px;
  background: var(--blue-50);
  display: grid;
  place-items: center;
}
.app-icon svg { width: 28px; height: 28px; stroke: var(--blue-600); }
.app-card h3 { font-size: 17px; margin-bottom: 6px; }
.app-card p { font-size: 13px; color: var(--ink-400); margin-bottom: 16px; }
.app-card .dl-link {
  font-size: 14px;
  font-weight: 600;
  color: var(--blue-600);
}

/* ============================================================
   Privacy (dark)
   ============================================================ */
.privacy {
  background: var(--bg-dark);
  color: #fff;
  position: relative;
  overflow: hidden;
}
.privacy::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(600px 300px at 20% 20%, rgba(46,143,230,.15), transparent 60%),
    radial-gradient(500px 300px at 80% 80%, rgba(46,143,230,.08), transparent 60%);
  pointer-events: none;
}
.privacy .section-head h2 { color: #fff; }
.privacy .lead { color: rgba(255,255,255,.7); }
.privacy-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  position: relative;
}
.privacy-card {
  background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.08);
  border-radius: var(--radius-md);
  padding: 32px;
}
.privacy-card .p-icon {
  width: 44px; height: 44px;
  border-radius: 10px;
  background: rgba(46,143,230,.15);
  display: grid; place-items: center;
  margin-bottom: 18px;
  color: var(--blue-400);
}
.privacy-card h3 { font-size: 18px; margin-bottom: 10px; color: #fff; }
.privacy-card p { font-size: 14px; color: rgba(255,255,255,.65); line-height: 1.7; }

/* ============================================================
   CTA
   ============================================================ */
.cta-band {
  background: linear-gradient(135deg, var(--blue-600), var(--blue-500));
  color: #fff;
  text-align: center;
  border-radius: var(--radius-xl);
  padding: 80px 40px;
  margin: 0 auto;
  max-width: var(--max-w);
}
.cta-band h2 { color: #fff; margin-bottom: 16px; }
.cta-band p { color: rgba(255,255,255,.85); max-width: 520px; margin: 0 auto 32px; }
.cta-band .btn-white {
  background: #fff;
  color: var(--blue-700);
  box-shadow: 0 8px 24px rgba(0,0,0,.15);
}

/* ============================================================
   Footer
   ============================================================ */
.site-footer {
  background: var(--bg-dark);
  color: rgba(255,255,255,.7);
  padding: 80px 0 32px;
  margin-top: 100px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 48px;
}
.footer-brand img { height: 40px; width: 40px; border-radius: 10px; object-fit: cover; margin-bottom: 16px; }
.footer-brand p { font-size: 14px; line-height: 1.7; max-width: 280px; }
.footer-col h4 {
  color: #fff;
  font-size: 14px;
  margin-bottom: 18px;
  font-weight: 600;
}
.footer-col li { margin-bottom: 10px; }
.footer-col a { font-size: 14px; transition: color .2s; }
.footer-col a:hover { color: var(--blue-400); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.1);
  padding-top: 28px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 13px;
  color: rgba(255,255,255,.4);
}

/* ============================================================
   Reveal animation
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .7s ease, transform .7s ease;
}
.reveal.in {
  opacity: 1;
  transform: none;
}

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 900px) {
  .nav-links, .nav-cta .btn-ghost { display: none; }
  .menu-toggle { display: flex; }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%; left: 0; right: 0;
    background: #fff;
    padding: 20px 24px;
    border-bottom: 1px solid var(--line);
    gap: 16px;
  }
  section { padding: 64px 0; }
  .hero { padding: 140px 0 60px; }
  .feature-row { grid-template-columns: 1fr; gap: 32px; padding: 40px 0; }
  .feature-row.reverse .feature-media { order: 0; }
  .apps-grid { grid-template-columns: repeat(2, 1fr); }
  .privacy-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 32px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .cta-band { padding: 56px 24px; }
}
@media (max-width: 560px) {
  .apps-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .stat-num { font-size: 28px; }
}