/* ---- Tokens ---- */
:root {
  --bg: #fdfbf6;
  --surface: #ffffff;
  --text: #1c1917;
  --text-sub: #57534e;
  --text-muted: #78716c;
  --border: #e7e2d8;
  --border-strong: #d6cfbe;
  --primary: #1c1917;
  --shadow-sm: 0 1px 2px rgba(28, 25, 23, 0.04);
  --shadow-md: 0 8px 24px rgba(28, 25, 23, 0.08), 0 2px 4px rgba(28, 25, 23, 0.04);
  --shadow-lg: 0 16px 40px rgba(28, 25, 23, 0.12), 0 4px 8px rgba(28, 25, 23, 0.05);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --font-zh: "PingFang SC", "Noto Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-en: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-en);
  font-size: 18px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

/* ---- Bilingual visibility ---- */
body.zh .en { display: none; }
body:not(.zh) .zh { display: none; }
/* Chinese text uses CN font; only when shown */
body.zh .zh,
body.zh h1.brand-title,
body.zh .lede,
body.zh .card-title,
body.zh .card-desc,
body.zh .card-cta,
body.zh .qr-heading,
body.zh .qr-sub,
body.zh .site-footer p { font-family: var(--font-zh); }

/* ---- Header ---- */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 22px 32px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: saturate(140%) blur(8px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}
.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 12px;
  background: linear-gradient(135deg, #d4541c 0%, #2d6a4f 100%);
  color: #fff;
  flex-shrink: 0;
}
.brand-title {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.01em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
body.zh .brand-title { font-size: 24px; }

.lang-toggle {
  appearance: none;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--text);
  font-family: inherit;
  font-size: 15px;
  font-weight: 600;
  padding: 8px 16px;
  min-height: 44px;
  min-width: 44px;
  border-radius: 999px;
  cursor: pointer;
  transition: background-color 120ms ease, border-color 120ms ease, transform 120ms ease;
}
.lang-toggle:hover { background: #f5f1e8; border-color: #b8b09a; }
.lang-toggle:active { transform: scale(0.97); }
.lang-toggle:focus-visible { outline: 2px solid var(--text); outline-offset: 2px; }

/* ---- Container ---- */
.container {
  flex: 1;
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 56px 32px 80px;
}

/* ---- Intro ---- */
.intro { margin-bottom: 40px; max-width: 720px; }
.lede {
  margin: 0;
  font-size: 19px;
  line-height: 1.6;
  color: var(--text-sub);
}
body.zh .lede { font-size: 20px; line-height: 1.7; }

/* ---- Cards grid ----
   5 cards. To avoid an empty trailing slot:
   - ≥1024px: 6-col grid; cards 1-3 span 2 cols (full row), cards 4-5 span 2 cols
              and offset so they center on row 2 (cols 2-3 and 4-5).
   - 720-1023px: 4-col grid; cards 1-4 span 2 cols, card 5 spans cols 2-3 (centered).
   - <720px: 1 col. */
.cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-bottom: 64px;
}
@media (min-width: 720px) {
  .cards { grid-template-columns: repeat(4, 1fr); }
  .card { grid-column: span 2; }
  .card:nth-child(5) { grid-column: 2 / span 2; }
}
@media (min-width: 1024px) {
  .cards { grid-template-columns: repeat(6, 1fr); }
  .card { grid-column: span 2; }
  .card:nth-child(4) { grid-column: 2 / span 2; }
  .card:nth-child(5) { grid-column: 4 / span 2; }
}

.card {
  position: relative;
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: inherit;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: var(--card-color, var(--border-strong));
}
.card:focus-visible {
  outline: 3px solid var(--card-color, var(--text));
  outline-offset: 3px;
}

.card-band {
  height: 6px;
  background: var(--card-color, var(--text));
}

.card-body {
  padding: 28px 24px 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  flex: 1;
}

.card-num {
  font-family: var(--font-en);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--card-color-strong, var(--text-muted));
  text-transform: uppercase;
}

.card-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: var(--card-bg, #f5f5f4);
  color: var(--card-color, var(--text));
  margin-bottom: 4px;
}

.card-title {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text);
}
body.zh .card-title { font-size: 26px; line-height: 1.3; }

.card-desc {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.55;
  color: var(--text-sub);
  flex: 1;
}
body.zh .card-desc { font-size: 17px; line-height: 1.7; }

.card-cta {
  margin-top: 12px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 15px;
  font-weight: 600;
  color: var(--card-color-strong, var(--text));
  transition: gap 180ms ease;
}
body.zh .card-cta { font-size: 16px; }
.card:hover .card-cta { gap: 10px; }

/* ---- QR block ---- */
.qr-block {
  display: flex;
  align-items: center;
  gap: 32px;
  padding: 32px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}
.qr-text { flex: 1; min-width: 0; }
.qr-heading {
  margin: 0 0 8px;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.01em;
}
body.zh .qr-heading { font-size: 26px; }
.qr-sub {
  margin: 0 0 12px;
  color: var(--text-sub);
  font-size: 15.5px;
  line-height: 1.6;
}
body.zh .qr-sub { font-size: 17px; line-height: 1.7; }
.qr-url a {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 14px;
  color: var(--text);
  text-decoration: none;
  background: #f5f1e8;
  padding: 4px 10px;
  border-radius: 6px;
  display: inline-block;
}
.qr-url a:hover { background: #ebe6d8; }
.qr-canvas {
  flex-shrink: 0;
  width: 160px;
  height: 160px;
  background: #fff;
  border-radius: 0;
  padding: 8px;
  border: 1px solid var(--border-strong);
  display: flex;
  align-items: center;
  justify-content: center;
}
.qr-canvas img { display: block; max-width: 100%; height: auto; }

/* ---- Footer ---- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 32px;
  background: var(--surface);
  text-align: center;
  color: var(--text-muted);
  font-size: 14px;
}
.site-footer p { margin: 0; }

/* ---- Responsive (small screens) ---- */
@media (max-width: 720px) {
  .site-header { padding: 14px 16px; }
  .brand { gap: 10px; min-width: 0; flex: 1; }
  .brand-mark { width: 36px; height: 36px; border-radius: 10px; }
  .brand-mark svg { width: 22px; height: 22px; }
  .brand-title { font-size: 17px; }
  body.zh .brand-title { font-size: 19px; }
  .lang-toggle { padding: 7px 14px; font-size: 14px; flex-shrink: 0; }
  .container { padding: 32px 20px 56px; }
  .intro { margin-bottom: 28px; }
  .lede { font-size: 17px; }
  body.zh .lede { font-size: 18px; }
  .cards { gap: 16px; margin-bottom: 40px; }
  .card-body { padding: 24px 20px 20px; }
  .card-title { font-size: 20px; }
  body.zh .card-title { font-size: 22px; }
  .qr-block { flex-direction: column; padding: 24px 20px; gap: 20px; text-align: center; align-items: center; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
}