/* ===== Reset & Base ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue",
    "Microsoft YaHei", sans-serif;
  color: #1C1C1E;
  background: #FFFFFF;
  line-height: 1.6;
}
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

.container {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Header ===== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid #F0F0F2;
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
  letter-spacing: 1px;
}
.logo img { width: 32px; height: 32px; border-radius: 8px; }

.nav-links { display: flex; gap: 28px; }
.nav-links a {
  font-size: 14px;
  color: #636366;
  transition: color .2s;
}
.nav-links a:hover { color: #1C1C1E; }

@media (max-width: 720px) {
  .nav-links { display: none; }
}

/* ===== Hero ===== */
.hero {
  padding: 80px 0 100px;
  background:
    radial-gradient(1000px 500px at 50% -100px, #F2F2F7 0%, transparent 70%),
    #FFFFFF;
  text-align: center;
}
.hero-inner { display: flex; flex-direction: column; align-items: center; }
.hero-logo {
  width: 96px;
  height: 96px;
  border-radius: 22px;
  margin-bottom: 28px;
  box-shadow: 0 20px 60px -20px rgba(0, 0, 0, 0.18);
}
.hero-title {
  font-size: 64px;
  font-weight: 800;
  letter-spacing: 4px;
  margin-bottom: 6px;
}
.hero-slogan {
  font-size: 18px;
  color: #8E8E93;
  letter-spacing: 4px;
  margin-bottom: 28px;
  text-transform: uppercase;
}
.hero-sub {
  font-size: 17px;
  color: #636366;
  max-width: 520px;
  margin-bottom: 40px;
}
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; justify-content: center; }

.btn {
  display: inline-block;
  padding: 14px 32px;
  border-radius: 12px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 1px;
  transition: transform .15s, background .2s, color .2s;
}
.btn:active { transform: scale(0.97); }
.btn-primary { background: #1C1C1E; color: #FFFFFF; }
.btn-primary:hover { background: #000000; }
.btn-secondary {
  background: #F2F2F7;
  color: #1C1C1E;
}
.btn-secondary:hover { background: #E5E5EA; }

/* ===== Sections ===== */
.section { padding: 100px 0; }
.section-alt { background: #FAFAFA; }
.section-title {
  font-size: 38px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
  letter-spacing: 1px;
}
.section-sub {
  font-size: 16px;
  color: #8E8E93;
  text-align: center;
  margin-bottom: 56px;
}

/* ===== Features ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
@media (max-width: 900px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .features-grid { grid-template-columns: 1fr; }
}

.feature-card {
  background: #FFFFFF;
  border: 1px solid #F0F0F2;
  border-radius: 18px;
  padding: 32px 28px;
  transition: transform .25s, box-shadow .25s, border-color .25s;
}
.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20px 50px -20px rgba(0, 0, 0, 0.1);
  border-color: #E5E5EA;
}
.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: #F2F2F7;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
  color: #1C1C1E;
}
.feature-icon i { font-size: 20px; line-height: 1; }
.feature-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
}
.feature-card p {
  font-size: 14px;
  color: #636366;
  line-height: 1.7;
}

/* ===== Models ===== */
.models-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}
.model-chip {
  background: #FFFFFF;
  border: 1px solid #E5E5EA;
  padding: 12px 22px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  color: #1C1C1E;
  transition: all .2s;
}
.model-chip:hover {
  background: #1C1C1E;
  color: #FFFFFF;
  border-color: #1C1C1E;
  transform: translateY(-2px);
}

/* ===== Download ===== */
.section-cta {
  background: #FAFAFA;
  text-align: center;
}
.download-buttons {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 16px;
}
.dl-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  background: #1C1C1E;
  color: #FFFFFF;
  padding: 14px 26px;
  border-radius: 12px;
  min-width: 180px;
  transition: background .2s, transform .15s;
}
.dl-btn:hover { background: #000000; transform: translateY(-2px); }
.dl-label {
  font-size: 11px;
  color: #8E8E93;
  text-transform: uppercase;
  letter-spacing: 1px;
}
.dl-store { font-size: 17px; font-weight: 700; margin-top: 2px; }
.download-note {
  font-size: 13px;
  color: #8E8E93;
  margin-top: 16px;
}

/* ===== Footer ===== */
.footer {
  background: #FAFAFA;
  border-top: 1px solid #F0F0F2;
  padding: 56px 0 28px;
}
.footer-inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 32px;
  padding-bottom: 32px;
}
@media (max-width: 700px) {
  .footer-inner { grid-template-columns: 1fr 1fr; }
}
.footer-col h4 {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 14px;
}
.footer-col a {
  display: block;
  font-size: 13px;
  color: #636366;
  margin-bottom: 8px;
  transition: color .2s;
}
.footer-col a:hover { color: #1C1C1E; }
.footer-tagline {
  font-size: 13px;
  color: #8E8E93;
  margin-top: 10px;
  letter-spacing: 1px;
}

.footer-bottom {
  border-top: 1px solid #E5E5EA;
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 12px;
  color: #8E8E93;
}
.footer-bottom .icp a:hover { color: #1C1C1E; }

/* ===== Legal pages (terms / privacy) ===== */
.legal {
  max-width: 820px;
  margin: 0 auto;
  padding: 80px 24px 100px;
}
.legal h1 {
  font-size: 36px;
  font-weight: 700;
  margin-bottom: 8px;
}
.legal .meta {
  font-size: 13px;
  color: #8E8E93;
  margin-bottom: 40px;
}
.legal h2 {
  font-size: 20px;
  font-weight: 700;
  margin: 36px 0 12px;
}
.legal p, .legal li {
  font-size: 15px;
  color: #3A3A3C;
  line-height: 1.85;
  margin-bottom: 12px;
}
.legal ul, .legal ol {
  padding-left: 24px;
  margin-bottom: 12px;
}

/* ===== Dark mode ===== */
@media (prefers-color-scheme: dark) {
  body { background: #000000; color: #FFFFFF; }
  .header {
    background: rgba(0, 0, 0, 0.85);
    border-bottom-color: #1C1C1E;
  }
  .nav-links a { color: #8E8E93; }
  .nav-links a:hover { color: #FFFFFF; }

  .hero {
    background:
      radial-gradient(1000px 500px at 50% -100px, #1C1C1E 0%, transparent 70%),
      #000000;
  }
  .hero-slogan { color: #636366; }
  .hero-sub { color: #8E8E93; }

  .btn-primary { background: #FFFFFF; color: #000000; }
  .btn-primary:hover { background: #E5E5EA; }
  .btn-secondary { background: #1C1C1E; color: #FFFFFF; }
  .btn-secondary:hover { background: #2C2C2E; }

  .section-alt, .section-cta, .footer { background: #0A0A0A; }
  .section-sub { color: #636366; }

  .feature-card {
    background: #0A0A0A;
    border-color: #1C1C1E;
  }
  .feature-card p { color: #8E8E93; }
  .feature-icon {
    background: #1C1C1E;
    color: #FFFFFF;
  }

  .model-chip {
    background: #0A0A0A;
    border-color: #1C1C1E;
    color: #FFFFFF;
  }
  .model-chip:hover {
    background: #FFFFFF;
    color: #000000;
    border-color: #FFFFFF;
  }

  .dl-btn { background: #FFFFFF; color: #000000; }
  .dl-btn:hover { background: #E5E5EA; }
  .dl-label { color: #636366; }

  .footer { border-top-color: #1C1C1E; }
  .footer-col a { color: #8E8E93; }
  .footer-col a:hover { color: #FFFFFF; }
  .footer-bottom { border-top-color: #1C1C1E; color: #636366; }

  .legal p, .legal li { color: #C7C7CC; }
}