:root {
  --brand: #023f9f;
  --brand-2: #1d6bf0;
  --bg: #f6f8fc;
  --surface: #ffffff;
  --text: #0f1b33;
  --muted: #5a6680;
  --line: #e3e8f2;
  --radius: 20px;
  --shadow: 0 10px 30px rgba(2, 63, 159, 0.08);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1222;
    --surface: #121b30;
    --text: #e8eefb;
    --muted: #9aa6c0;
    --line: #22304d;
    --shadow: 0 10px 30px 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: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--brand-2); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Bilingual: show only the active language */
html[data-lang="en"] [lang="zh"],
html[data-lang="zh"] [lang="en"] { display: none !important; }

.wrap { max-width: 1120px; margin: 0 auto; padding: 0 20px; }

/* Header */
header.site {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
header.site .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 16px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
  color: var(--text);
}
.brand:hover { text-decoration: none; }
.brand img { width: 32px; height: 32px; border-radius: 8px; }
nav.links { display: flex; align-items: center; gap: 22px; font-size: 15px; }
nav.links a { color: var(--muted); }
nav.links a:hover { color: var(--text); text-decoration: none; }
.lang-btn {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--text);
  border-radius: 999px;
  padding: 6px 14px;
  font: inherit;
  font-size: 14px;
  cursor: pointer;
}

/* Hero */
.hero { padding: 96px 0 72px; text-align: center; }
.hero h1 {
  font-size: clamp(34px, 6vw, 58px);
  line-height: 1.12;
  margin: 0 0 18px;
  letter-spacing: -0.02em;
}
.hero h1 .accent {
  background: linear-gradient(90deg, var(--brand), var(--brand-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero p { color: var(--muted); font-size: clamp(16px, 2.2vw, 19px); max-width: 640px; margin: 0 auto 32px; }
.btn {
  display: inline-block;
  background: var(--brand);
  color: #fff;
  padding: 12px 26px;
  border-radius: 999px;
  font-weight: 600;
}
.btn:hover { text-decoration: none; background: var(--brand-2); }
.btn.ghost { background: transparent; color: var(--text); border: 1px solid var(--line); }
.btn.ghost:hover { background: var(--surface); }

/* App cards */
.section-title { text-align: center; font-size: clamp(26px, 4vw, 36px); margin: 0 0 8px; }
.section-sub { text-align: center; color: var(--muted); margin: 0 0 40px; }
.cards { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 22px; padding-bottom: 40px; }
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  color: inherit;
  transition: transform .2s ease;
}
.card:hover { text-decoration: none; }
.card:hover { transform: translateY(-4px); }
.card h3 { margin: 18px 0 6px; font-size: 22px; }
.card p { color: var(--muted); margin: 0 0 20px; flex: 1; }
.card .more { font-weight: 600; }

.app-icon {
  display: block;
  width: 64px;
  height: 64px;
  border-radius: 16px;
  box-shadow: 0 4px 12px rgba(15, 27, 51, 0.15);
}
.app-icon.lg { width: 96px; height: 96px; border-radius: 24px; }

/* App detail sections */
.app {
  padding: 72px 0;
  border-top: 1px solid var(--line);
  scroll-margin-top: 64px;
}
.app .grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 48px; align-items: center; }
.app h2 { font-size: clamp(28px, 4vw, 40px); margin: 18px 0 8px; }
.app .tagline { color: var(--muted); font-size: 18px; margin: 0 0 22px; }
.features { list-style: none; padding: 0; margin: 0 0 28px; display: grid; gap: 12px; }
.features li { display: flex; gap: 10px; align-items: flex-start; }
.features li > span { flex: 1; }
.features li::before {
  content: "";
  flex: none;
  width: 20px;
  height: 20px;
  margin-top: 3px;
  border-radius: 50%;
  background: var(--brand-2) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M5 12l5 5L20 7'/%3E%3C/svg%3E") center/12px no-repeat;
}
.stores { display: flex; flex-wrap: wrap; gap: 12px; }
.store {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--text);
  color: var(--bg);
  padding: 10px 18px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 14px;
}
.store:hover { text-decoration: none; opacity: .9; }
.store svg { width: 20px; height: 20px; }
.store.ghost { background: transparent; color: var(--text); border: 1px solid var(--line); }
.note { margin: 14px 0 0; font-size: 14px; color: var(--muted); }
.legal-links { margin-top: 18px; font-size: 14px; color: var(--muted); }
.qr {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  padding: 8px 16px 8px 8px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  color: var(--muted);
  font-size: 13px;
}
.qr:hover { text-decoration: none; border-color: var(--brand-2); }
.app-head { display: flex; align-items: center; gap: 20px; flex-wrap: wrap; }
.qr img { display: block; width: 80px; height: 80px; border-radius: 8px; background: #fff; }
.qr strong { display: block; color: var(--text); font-size: 15px; margin-bottom: 2px; }

/* App visuals */
.feature-img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  box-shadow: var(--shadow), 0 30px 60px rgba(2, 63, 159, 0.18);
}
.shots { display: flex; justify-content: center; align-items: flex-start; gap: 20px; }
.shots img {
  width: min(46%, 240px);
  height: auto;
  border-radius: 28px;
  border: 8px solid #0f1b33;
  box-shadow: var(--shadow), 0 30px 60px rgba(2, 63, 159, 0.18);
}

/* Contact / footer */
.contact { padding: 80px 0; text-align: center; border-top: 1px solid var(--line); }
.contact p { color: var(--muted); }
footer.site { border-top: 1px solid var(--line); padding: 28px 0; color: var(--muted); font-size: 14px; }
footer.site .wrap { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; }
footer.site nav { display: flex; gap: 18px; }
footer.site a { color: var(--muted); }

/* Legal pages */
.legal { padding: 56px 0 80px; max-width: 820px; }
.legal h1 { font-size: clamp(28px, 4vw, 38px); margin-bottom: 4px; }
.legal .updated { color: var(--muted); margin-top: 0; }
.legal h2 { margin-top: 36px; font-size: 22px; }
.legal p, .legal li { color: var(--text); }
.legal .toc { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 16px 22px; }

@media (max-width: 480px) {
  .qr { padding: 8px; }
  .qr > span { display: none; }
}

@media (max-width: 900px) {
  .cards { grid-template-columns: 1fr; }
  .app .grid { grid-template-columns: 1fr; gap: 32px; }
  nav.links a.hide-sm { display: none; }
}