/* ============================================================
   AntMessenger — Official Site Stylesheet
   Theme: 浅蓝 / Clean Sky Blue
   ============================================================ */

:root {
  --blue-600: #0A84FF;
  --blue-700: #0066D6;
  --blue-500: #3DA0FF;
  --blue-100: #E3F0FF;
  --blue-50:  #F2F8FF;

  --ink-900: #0B1B2B;
  --ink-700: #1E3A5F;
  --ink-500: #47617D;
  --ink-400: #6B8299;

  --line:    #DCEBFB;
  --bg:      #FFFFFF;
  --bg-soft: #F5FAFF;

  --accent:  #06B6D4;
  --ok:      #10B981;

  --radius-lg: 22px;
  --radius-md: 14px;
  --radius-sm: 10px;

  --shadow-sm: 0 2px 8px rgba(10, 132, 255, .06);
  --shadow-md: 0 12px 32px rgba(10, 132, 255, .10);
  --shadow-lg: 0 24px 60px rgba(10, 132, 255, .16);

  --container: 1200px;
  --font: "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI",
          "PingFang SC", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  color: var(--ink-900);
  background: var(--bg);
  line-height: 1.65;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* ============ Buttons ============ */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 8px; border-radius: 999px; font-weight: 600;
  padding: 12px 26px; transition: all .2s ease; cursor: pointer;
  border: 1px solid transparent; white-space: nowrap;
}
.btn-primary {
  background: linear-gradient(135deg, var(--blue-600), var(--blue-700));
  color: #fff; box-shadow: 0 8px 20px rgba(10,132,255,.30);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 26px rgba(10,132,255,.40); }
.btn-ghost {
  background: transparent; color: var(--ink-900);
  border-color: var(--line);
}
.btn-ghost:hover { background: var(--blue-50); border-color: var(--blue-500); }
.btn-sm { padding: 9px 18px; font-size: 14px; }
.btn-lg { padding: 15px 32px; font-size: 16px; }

/* ============ Header ============ */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.85);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color .2s, box-shadow .2s;
}
.site-header.scrolled {
  border-bottom-color: var(--line);
  box-shadow: var(--shadow-sm);
}
.nav-wrap {
  display: flex; align-items: center; justify-content: space-between;
  height: 72px;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand-logo { width: 38px; height: 38px; border-radius: 10px; object-fit: contain; }
.brand-name {
  font-size: 20px; font-weight: 700; letter-spacing: -.01em;
}
.brand-name em {
  font-style: normal; color: var(--blue-600);
}
.main-nav { display: flex; gap: 28px; }
.main-nav a {
  font-size: 15px; color: var(--ink-500); font-weight: 500;
  transition: color .2s;
}
.main-nav a:hover { color: var(--blue-600); }
.nav-actions { display: flex; align-items: center; gap: 12px; }

.nav-toggle {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: 0; cursor: pointer; padding: 8px;
}
.nav-toggle span {
  width: 22px; height: 2px; background: var(--ink-900);
  border-radius: 2px; transition: transform .2s, opacity .2s;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============ Hero ============ */
.hero {
  background:
    radial-gradient(1200px 600px at 85% -10%, #D8EBFF 0%, rgba(216,235,255,0) 60%),
    linear-gradient(180deg, #F2F8FF 0%, #FFFFFF 80%);
  padding: 72px 0 96px;
  overflow: hidden;
}
.hero-grid {
  display: grid; grid-template-columns: 1.05fr 1fr;
  gap: 48px; align-items: center;
}
.eyebrow {
  display: inline-block;
  font-size: 13px; font-weight: 600; letter-spacing: .08em;
  color: var(--blue-700); background: var(--blue-100);
  padding: 6px 14px; border-radius: 999px; margin-bottom: 20px;
}
.hero h1 {
  font-size: clamp(36px, 5vw, 60px);
  line-height: 1.12; font-weight: 800;
  letter-spacing: -.02em; margin-bottom: 22px;
}
.hl {
  background: linear-gradient(120deg, var(--blue-600), var(--accent));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.lead {
  font-size: 17px; color: var(--ink-500); max-width: 540px;
  margin-bottom: 30px;
}
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 36px; }
.hero-meta {
  display: flex; gap: 28px; flex-wrap: wrap;
  font-size: 14px; color: var(--ink-400);
}
.hero-meta strong { color: var(--ink-900); font-size: 16px; margin-right: 4px; }

.hero-visual { position: relative; }
.hero-glow {
  position: absolute; inset: 8% -10% -5% -10%;
  background: radial-gradient(closest-side, rgba(10,132,255,.20), transparent 70%);
  filter: blur(20px); z-index: 0;
}
.hero-img {
  position: relative; z-index: 1;
  border-radius: 28px;
  box-shadow: var(--shadow-lg);
  height: auto;
}

/* ============ Trust Bar ============ */
.trust-bar {
  background: #fff; border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 36px 0;
}
.trust-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px;
  text-align: center;
}
.trust-num {
  display: block; font-size: 32px; font-weight: 800;
  color: var(--blue-600); letter-spacing: -.02em;
}
.trust-label { font-size: 14px; color: var(--ink-400); }

/* ============ Sections ============ */
.section { padding: 96px 0; }
.section-alt { background: var(--bg-soft); }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 56px; }
.section-head h2 {
  font-size: clamp(28px, 3.6vw, 42px);
  font-weight: 800; letter-spacing: -.02em; margin-bottom: 14px;
}
.section-sub { color: var(--ink-500); font-size: 17px; }

/* ============ Feature Grid ============ */
.feature-grid {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 28px;
}
.feature-card {
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius-lg); overflow: hidden;
  transition: transform .25s ease, box-shadow .25s ease;
}
.feature-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.feature-media {
  background: linear-gradient(180deg, #F2F8FF, #fff);
  padding: 28px; display: flex; align-items: center; justify-content: center;
}
.feature-media img { max-height: 260px; object-fit: contain; }
.feature-body { padding: 28px 32px 34px; }
.feature-body h3 {
  font-size: 22px; font-weight: 700; margin-bottom: 10px;
}
.feature-body p { color: var(--ink-500); font-size: 15px; }

/* ============ Split (Security / Devices) ============ */
.split {
  display: grid; grid-template-columns: 1fr 1fr; gap: 64px;
  align-items: center;
}
.split.reverse .split-copy { order: 2; }
.split.reverse .split-visual { order: 1; }
.split-copy h2 {
  font-size: clamp(28px, 3.4vw, 40px); font-weight: 800;
  letter-spacing: -.02em; margin-bottom: 18px;
}
.check-list { margin: 22px 0 30px; display: grid; gap: 12px; }
.check-list li {
  position: relative; padding-left: 30px; color: var(--ink-700);
}
.check-list li::before {
  content: ""; position: absolute; left: 0; top: 6px;
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--blue-100) url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="%230A84FF" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"><polyline points="20 6 9 17 4 12"/></svg>') center/12px no-repeat;
}
.split-visual img {
  border-radius: var(--radius-lg); box-shadow: var(--shadow-md);
  height: auto; width: 100%;
}
.platform-list {
  margin: 22px 0 30px; display: grid; gap: 14px;
}
.platform-list li {
  display: flex; justify-content: space-between; align-items: center;
  padding: 14px 18px; background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius-md);
}
.platform-list li span { color: var(--ink-400); font-size: 14px; }

/* ============ CTA Band ============ */
.cta-band {
  background:
    radial-gradient(800px 300px at 20% 0%, rgba(255,255,255,.25), transparent 60%),
    linear-gradient(135deg, #0A84FF 0%, #0066D6 100%);
  color: #fff; text-align: center; border-radius: 0;
}
.cta-inner h2 { font-size: clamp(28px, 3.4vw, 40px); font-weight: 800; margin-bottom: 12px; }
.cta-inner p { opacity: .9; font-size: 17px; margin-bottom: 30px; }
.store-row {
  display: flex; gap: 14px; justify-content: center; flex-wrap: wrap;
  margin-bottom: 22px;
}
.store-btn {
  display: inline-flex; flex-direction: column; align-items: flex-start;
  background: #0B1B2B; color: #fff;
  padding: 10px 22px; border-radius: 12px; min-width: 170px;
  transition: transform .2s, background .2s;
}
.store-btn:hover { transform: translateY(-2px); background: #000; }
.store-label { font-size: 11px; opacity: .8; }
.store-name { font-size: 16px; font-weight: 600; }
.cta-note { font-size: 13px; opacity: .8; }

/* ============ Value Grid (Enterprise) ============ */
.value-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px;
}
.value-card {
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius-md); padding: 26px;
  transition: border-color .2s, transform .2s;
}
.value-card:hover { border-color: var(--blue-500); transform: translateY(-3px); }
.value-card h3 { font-size: 18px; margin-bottom: 8px; color: var(--ink-900); }
.value-card p { font-size: 14px; color: var(--ink-500); }

/* ============ FAQ ============ */
.faq-wrap { max-width: 820px; }
.faq-list { display: grid; gap: 12px; }
.faq-item {
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius-md); padding: 0 22px;
}
.faq-item summary {
  cursor: pointer; padding: 18px 0; font-weight: 600;
  list-style: none; position: relative; padding-right: 30px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+"; position: absolute; right: 4px; top: 50%;
  transform: translateY(-50%); font-size: 22px; font-weight: 400;
  color: var(--blue-600); transition: transform .2s;
}
.faq-item[open] summary::after { transform: translateY(-50%) rotate(45deg); }
.faq-item p { padding: 0 0 20px; color: var(--ink-500); font-size: 15px; }

/* ============ Footer ============ */
.site-footer {
  background: #0B1B2B; color: #B8C7D9; padding: 64px 0 28px;
  margin-top: 0;
}
.footer-grid {
  display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 40px;
  margin-bottom: 40px;
}
.footer-brand p { font-size: 14px; margin-top: 14px; line-height: 1.7; }
.brand-name.light { color: #fff; }
.footer-col h4 {
  color: #fff; font-size: 14px; margin-bottom: 16px; font-weight: 600;
}
.footer-col a {
  display: block; font-size: 14px; margin-bottom: 10px;
  color: #B8C7D9; transition: color .2s;
}
.footer-col a:hover { color: #fff; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.08); padding-top: 22px;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px;
  font-size: 13px; color: #7E93AA;
}

/* ============ Toast ============ */
.toast {
  position: fixed; left: 50%; bottom: 32px; transform: translateX(-50%) translateY(20px);
  background: var(--ink-900); color: #fff; padding: 12px 22px;
  border-radius: 999px; font-size: 14px; opacity: 0;
  pointer-events: none; transition: all .25s ease; z-index: 100;
  box-shadow: 0 10px 30px rgba(0,0,0,.25);
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ============ Reveal Animation ============ */
.reveal {
  opacity: 0; transform: translateY(24px);
  transition: opacity .6s ease, transform .6s ease;
}
.reveal.visible { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}

/* ============ Responsive ============ */
@media (max-width: 960px) {
  .main-nav {
    position: fixed; top: 72px; left: 0; right: 0;
    background: #fff; flex-direction: column; gap: 0;
    border-bottom: 1px solid var(--line);
    padding: 12px 24px 20px;
    transform: translateY(-120%); transition: transform .25s ease;
    box-shadow: var(--shadow-md);
  }
  .main-nav.open { transform: translateY(0); }
  .main-nav a {
    padding: 14px 0; border-bottom: 1px solid var(--line);
    min-height: 48px; display: flex; align-items: center;
  }
  .main-nav a:last-child { border-bottom: 0; }
  .nav-toggle { display: flex; }

  .hero { padding: 48px 0 64px; }
  .hero-grid, .split { grid-template-columns: 1fr; gap: 36px; }
  .split.reverse .split-copy { order: 1; }
  .split.reverse .split-visual { order: 2; }

  .feature-grid { grid-template-columns: 1fr; }
  .value-grid { grid-template-columns: repeat(2, 1fr); }
  .trust-grid { grid-template-columns: repeat(2, 1fr); gap: 18px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 28px; }
  .section { padding: 64px 0; }
}
@media (max-width: 560px) {
  .value-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 34px; }
  .btn-lg { padding: 13px 24px; font-size: 15px; }
}