:root {
  --bg: #ffffff;
  --fg: #16181d;
  --muted: #8b8f98;
  --line: #ececef;
  --soft: #f6f7f9;
  --accent: #16181d;
  --radius: 14px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

.wrap { width: 100%; max-width: 1100px; margin: 0 auto; padding: 0 16px; }
.muted { color: var(--muted); }

/* ---------- header / footer ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 54px;
}
.brand { font-size: 17px; font-weight: 700; letter-spacing: 0.02em; }
.nav a { font-size: 14px; color: var(--muted); }
.nav a:hover { color: var(--fg); }

.site-footer {
  margin-top: 56px;
  padding: 28px 0 40px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  text-align: center;
}
.site-footer p { margin: 4px 0; }

/* ---------- hero ---------- */
.hero { padding: 44px 0 8px; }
.hero h1 {
  margin: 0;
  font-size: clamp(28px, 7vw, 44px);
  line-height: 1.2;
  letter-spacing: 0.04em;
}
.hero-tag { margin: 10px 0 0; font-size: 16px; color: var(--fg); }
.hero-desc { margin: 6px 0 0; font-size: 14px; color: var(--muted); }

/* ---------- sections ---------- */
.section { padding: 32px 0 0; }
.section-title { margin: 0 0 16px; font-size: 18px; font-weight: 700; }
.page-title { margin: 12px 0 4px; font-size: clamp(24px, 6vw, 34px); }
.page-meta { margin: 0; font-size: 13px; color: var(--muted); display: flex; gap: 12px; flex-wrap: wrap; }
.page-meta a { border-bottom: 1px solid var(--line); }
.page-meta a:hover { border-color: var(--fg); }
.page-desc { margin: 12px 0 0; color: #4a4f57; max-width: 68ch; }
.empty { color: var(--muted); padding: 32px 0; text-align: center; }

.crumbs { font-size: 13px; color: var(--muted); display: flex; gap: 6px; flex-wrap: wrap; }
.crumbs a:hover { color: var(--fg); }
.crumbs i { font-style: normal; color: var(--line); }

/* ---------- category grid ---------- */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}
.cat {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 14px 14px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--soft);
  transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
}
.cat:hover {
  transform: translateY(-2px);
  border-color: #dcdfe4;
  box-shadow: 0 8px 20px rgba(18, 20, 24, 0.07);
}
.cat-name { font-size: 15px; font-weight: 600; }
.cat-desc { font-size: 12px; color: var(--muted); }
.cat-count { margin-top: 6px; font-size: 12px; color: var(--muted); }

/* ---------- model cards ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}
.card { display: block; }
.card-thumb {
  aspect-ratio: 3 / 4;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--soft);
}
.card-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}
.card:hover .card-thumb img { transform: scale(1.04); }
.card-body { padding: 10px 2px 0; }
.card-title { margin: 0; font-size: 15px; font-weight: 600; }
.card-meta { margin: 4px 0 0; display: flex; gap: 6px; flex-wrap: wrap; }
.tag {
  font-size: 11px;
  line-height: 18px;
  padding: 0 8px;
  border-radius: 999px;
  background: var(--soft);
  color: var(--muted);
}

/* ---------- download button ---------- */
.btn-download {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  margin: 20px 0 4px;
  padding: 15px 20px;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  transition: opacity 0.18s ease;
}
.btn-download:hover { opacity: 0.88; }
.btn-main { font-size: 16px; font-weight: 700; }
.btn-sub { font-size: 12px; color: rgba(255, 255, 255, 0.72); }

/* ---------- photo grid ---------- */
.photo-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 22px;
}
.photo {
  aspect-ratio: 3 / 4;
  border-radius: 12px;
  overflow: hidden;
  background: var(--soft);
  cursor: zoom-in;
}
.photo img { width: 100%; height: 100%; object-fit: cover; }

/* ---------- lightbox ---------- */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 60;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(12, 13, 16, 0.94);
}
.lightbox[hidden] { display: none; }
.lb-img { max-width: 94vw; max-height: 86vh; object-fit: contain; border-radius: 6px; }
.lb-close, .lb-prev, .lb-next {
  position: absolute;
  border: 0;
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  cursor: pointer;
  border-radius: 50%;
  font-size: 20px;
  line-height: 1;
}
.lb-close { top: 14px; right: 14px; width: 38px; height: 38px; }
.lb-prev, .lb-next { top: 50%; transform: translateY(-50%); width: 44px; height: 44px; }
.lb-prev { left: 10px; }
.lb-next { right: 10px; }
.lb-close:hover, .lb-prev:hover, .lb-next:hover { background: rgba(255, 255, 255, 0.22); }
.lb-count {
  position: absolute;
  bottom: 18px;
  left: 50%;
  transform: translateX(-50%);
  color: rgba(255, 255, 255, 0.7);
  font-size: 13px;
}

/* ---------- larger screens ---------- */
@media (min-width: 640px) {
  .cat-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
  .card-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
  .photo-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
  .btn-download { max-width: 420px; margin-left: auto; margin-right: auto; }
}
@media (min-width: 900px) {
  .cat-grid { grid-template-columns: repeat(5, minmax(0, 1fr)); }
}
@media (min-width: 1024px) {
  .card-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}