:root {
  --bg: #f1f5f9;
  --card: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --border: #e2e8f0;
  --brand: #2563eb;
  --brand-dark: #1d4ed8;
  --brand-soft: #eff6ff;
  --shadow-sm: 0 1px 2px rgba(15,23,42,.04), 0 1px 3px rgba(15,23,42,.06);
  --shadow-md: 0 4px 6px -1px rgba(15,23,42,.08), 0 2px 4px -2px rgba(15,23,42,.06);
  --shadow-lg: 0 10px 15px -3px rgba(15,23,42,.10), 0 4px 6px -4px rgba(15,23,42,.08);
  --radius: 12px;
}
* { box-sizing: border-box; }
body { margin: 0; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif; background: var(--bg); color: var(--text); font-size: 14px; line-height: 1.6; padding-top: 56px; padding-bottom: 48px; -webkit-font-smoothing: antialiased; }
.topbar { position: fixed; top: 0; left: 0; right: 0; height: 56px; padding: 0 24px; background: linear-gradient(135deg, var(--brand) 0%, var(--brand-dark) 100%); display: flex; align-items: center; justify-content: center; z-index: 20; box-shadow: 0 2px 8px rgba(37,99,235,.25); box-sizing: border-box; }
.topbar h1 { font-size: 20px; margin: 0; font-weight: 700; color: #fff; text-align: center; letter-spacing: .5px; line-height: 56px; }
.topbar .back { color: #fff; text-decoration: none; font-size: 14px; position: absolute; left: 24px; top: 50%; transform: translateY(-50%); opacity: .92; padding: 6px 12px; border-radius: 8px; background: rgba(255,255,255,.12); transition: background .2s; }
.topbar .back:hover { opacity: 1; background: rgba(255,255,255,.22); }
.footer { position: fixed; bottom: 0; left: 0; right: 0; height: 48px; padding: 0 24px; background: #ffffff; color: var(--muted); text-align: center; font-size: 13px; border-top: 1px solid var(--border); z-index: 10; box-shadow: 0 -2px 8px rgba(15,23,42,.04); box-sizing: border-box; line-height: 48px; }
.footer span { line-height: 48px; }
.layout { display: grid; grid-template-columns: 300px 1fr; gap: 20px; padding: 4px 24px 4px; max-width: 1240px; margin: 0 auto; }
.pane { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; min-height: calc(100vh - 180px); box-shadow: var(--shadow-sm); }
.pane h2 { font-size: 12px; margin: 0 0 12px; color: var(--muted); font-weight: 600; text-transform: uppercase; letter-spacing: .8px; padding-bottom: 10px; border-bottom: 1px solid var(--border); }
.pane ul { list-style: none; margin: 0; padding: 0; }
.pane li { padding: 10px 12px; border-radius: 8px; cursor: pointer; transition: all .18s ease; display: flex; align-items: center; gap: 12px; margin-bottom: 4px; }
.pane li:hover { background: var(--brand-soft); transform: translateY(-1px); }
.pane li.active { background: linear-gradient(135deg, var(--brand), var(--brand-dark)); color: #fff; box-shadow: 0 4px 12px rgba(37,99,235,.30); }
.pane li.empty { color: var(--muted); cursor: default; text-align: center; padding: 32px 0; justify-content: center; font-size: 13px; }
.pane li.empty:hover { background: transparent; transform: none; }
.item-logo { width: 36px; height: 36px; border-radius: 8px; object-fit: cover; flex-shrink: 0; background: #e2e8f0; }
.item-logo.placeholder { display: flex; align-items: center; justify-content: center; color: #64748b; font-weight: 600; font-size: 15px; background: linear-gradient(135deg, #e2e8f0, #cbd5e1); }
.pane li.active .item-logo.placeholder { background: rgba(255,255,255,.22); color: #fff; }
.item-name { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-weight: 500; }
.sdk-info { flex: 1; min-width: 0; }
.sdk-item .name { font-weight: 600; font-size: 14px; }
.sdk-item .meta { font-size: 12px; color: var(--muted); margin-top: 3px; }
.sdk-item .desc { font-size: 13px; color: #475569; margin-top: 4px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sdk-item.active .meta, .sdk-item.active .desc { color: rgba(255,255,255,.85); }
.detail-layout { max-width: 1000px; margin: 4px auto 4px; padding: 0 16px; }
.detail-info { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px 32px; box-shadow: var(--shadow-md); }
.detail-info h2 { margin: 0 0 20px; font-size: 22px; }
.detail-header { display: flex; align-items: center; gap: 18px; margin-bottom: 24px; padding-bottom: 20px; border-bottom: 1px solid var(--border); }
.detail-header h2 { margin: 0; }
.detail-logo { width: 72px; height: 72px; border-radius: 14px; object-fit: cover; flex-shrink: 0; background: linear-gradient(135deg, #e2e8f0, #cbd5e1); box-shadow: var(--shadow-sm); }
.meta-table { width: 100%; border-collapse: collapse; margin-bottom: 20px; border-radius: 8px; overflow: hidden; }
.meta-table th { text-align: right; width: 130px; padding: 12px 16px; color: var(--muted); font-weight: 500; background: #f8fafc; border-bottom: 1px solid var(--border); }
.meta-table td { padding: 12px 16px; border-bottom: 1px solid var(--border); font-weight: 500; }
.meta-table tr:last-child th, .meta-table tr:last-child td { border-bottom: none; }
.section { margin-top: 28px; }
.section h3 { font-size: 16px; margin: 0 0 14px; padding-bottom: 8px; border-bottom: 2px solid var(--brand); color: var(--text); font-weight: 600; display: inline-block; }
.file-list { list-style: none; padding: 0; margin: 0; }
.file-list li { padding: 14px 16px; border: 1px solid var(--border); border-radius: 10px; margin-bottom: 8px; transition: all .18s ease; background: #fff; }
.file-list li:hover { border-color: var(--brand); box-shadow: var(--shadow-sm); transform: translateY(-1px); }
.file-list .file-row { display: flex; justify-content: space-between; align-items: center; gap: 12px; }
.file-list .file-desc { margin-top: 6px; font-size: 12px; color: var(--muted); line-height: 1.5; }
.file-list a { color: var(--brand); text-decoration: none; font-weight: 600; display: flex; align-items: center; gap: 8px; }
.file-list a::before { content: "↓"; display: inline-flex; width: 24px; height: 24px; background: var(--brand-soft); color: var(--brand); border-radius: 6px; align-items: center; justify-content: center; font-weight: 700; }
.file-list a:hover { color: var(--brand-dark); }
.file-list .size { color: var(--muted); font-size: 12px; background: #f1f5f9; padding: 4px 10px; border-radius: 12px; }
.image-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 16px; }
.image-grid a { display: block; border: 1px solid var(--border); border-radius: 10px; overflow: hidden; aspect-ratio: 1/1; box-shadow: var(--shadow-sm); transition: all .2s ease; cursor: zoom-in; }
.image-grid a:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); border-color: var(--brand); }
.image-grid img { width: 100%; height: 100%; object-fit: cover; display: block; }
.lightbox-overlay { position: fixed; inset: 0; background: rgba(15,23,42,.85); display: flex; align-items: center; justify-content: center; z-index: 100; padding: 32px; backdrop-filter: blur(4px); }
.lightbox-overlay img { max-width: 92vw; max-height: 88vh; border-radius: 8px; box-shadow: 0 20px 60px rgba(0,0,0,.5); }
.lightbox-close { position: fixed; top: 20px; right: 24px; color: #fff; font-size: 32px; cursor: pointer; line-height: 1; opacity: .8; user-select: none; }
.lightbox-close:hover { opacity: 1; }
.video-list { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: 14px; }
.video-list li video { width: 100%; border-radius: 10px; background: #000; box-shadow: var(--shadow-sm); }
.desc { margin: 20px 0; }
.desc h3 { margin: 0 0 10px; border: none; padding: 0; display: block; }
.desc p { margin: 0; white-space: pre-wrap; line-height: 1.7; color: #334155; }