:root {
  --bg: #f6f7f9;
  --card: #ffffff;
  --ink: #1c2430;
  --muted: #6b7683;
  --line: #e3e7ec;
  --brand: #2f5bd7;
  --brand-ink: #ffffff;
  --ok: #1a8f4c;
  --warn: #b7791f;
  --danger: #c23b3b;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(16, 24, 40, 0.06), 0 1px 2px rgba(16, 24, 40, 0.04);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.5;
}
a { color: var(--brand); }

.container { max-width: 1000px; margin: 0 auto; padding: 0 20px; }

/* ---------- header ---------- */
.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.site-header .container {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding-top: 16px; padding-bottom: 16px;
}
.site-title { font-size: 1.25rem; font-weight: 700; margin: 0; }
.site-title small { display: block; font-size: 0.8rem; font-weight: 400; color: var(--muted); }
.header-links a { margin-left: 16px; font-size: 0.9rem; text-decoration: none; color: var(--muted); }
.header-links a:hover { color: var(--ink); }
.header-links a.active { color: var(--brand); font-weight: 600; }

/* ---------- view toggle ---------- */
.view-toggle { display: inline-flex; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
.view-toggle button {
  border: none; background: var(--card); color: var(--muted); cursor: pointer;
  padding: 9px 12px; font-size: 0.88rem; font-weight: 600;
}
.view-toggle button + button { border-left: 1px solid var(--line); }
.view-toggle button.active { background: var(--brand); color: #fff; }

/* ---------- group toggle ---------- */
.group-toggle {
  display: inline-flex; align-items: center; gap: 6px; cursor: pointer;
  font-size: 0.9rem; font-weight: 600; color: var(--muted);
  padding: 9px 12px; border: 1px solid var(--line); border-radius: 10px; background: var(--card);
}
.group-toggle input { width: 15px; height: 15px; cursor: pointer; }

/* ---------- group headers (grouped sort) ---------- */
.group-head {
  grid-column: 1 / -1;
  display: flex; align-items: center; gap: 10px;
  font-size: 0.82rem; font-weight: 700; letter-spacing: 0.04em; text-transform: uppercase;
  color: var(--brand); padding: 14px 8px 6px;
  border-bottom: 1px solid var(--line); margin-bottom: 2px;
  cursor: pointer; user-select: none; border-radius: 8px 8px 0 0;
}
.group-head:hover { background: #f2f5fb; }
.group-head:focus-visible { outline: 2px solid var(--brand); outline-offset: -2px; }
.list .group-head { padding: 16px 14px 8px; }
.group-head .group-chevron { font-size: 0.7rem; width: 12px; text-align: center; color: var(--brand); }
.group-head .group-name { flex: 0 1 auto; }
.group-head .group-count {
  color: var(--muted); font-weight: 600; letter-spacing: 0; text-transform: none;
  background: #eef0f3; border-radius: 999px; padding: 1px 9px; font-size: 0.78rem;
}
.group-head.collapsed { border-bottom-color: transparent; margin-bottom: 0; opacity: 0.92; }

/* ---------- toolbar ---------- */
.toolbar {
  display: flex; flex-wrap: wrap; gap: 12px; align-items: center;
  margin: 24px 0 16px;
}
.toolbar input[type="search"],
.toolbar select {
  padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px;
  font-size: 0.95rem; background: var(--card); color: var(--ink);
}
.toolbar input[type="search"] { flex: 1 1 220px; }
.result-count { color: var(--muted); font-size: 0.88rem; margin-left: auto; white-space: nowrap; }

/* ---------- book grid ---------- */
.grid {
  display: grid; gap: 14px;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
}
.book-card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 16px; display: flex; flex-direction: column; gap: 6px;
  cursor: pointer; transition: transform 0.08s ease, box-shadow 0.12s ease, border-color 0.12s ease;
}
.book-card:hover { transform: translateY(-2px); border-color: #ccd6ea;
  box-shadow: 0 6px 16px rgba(16, 24, 40, 0.10); }
.book-card:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; }
.book-card .view-hint { font-size: 0.74rem; color: var(--brand); margin-top: 4px; font-weight: 600; }
.book-card h3 { margin: 0; font-size: 0.9rem; font-weight: 700; color: var(--ink); }
.book-card .author { color: var(--muted); font-size: 0.9rem; }
.book-card .meta { margin-top: auto; display: flex; flex-wrap: wrap; gap: 6px; padding-top: 8px; }

.badge {
  display: inline-block; font-size: 0.72rem; font-weight: 600;
  padding: 2px 8px; border-radius: 999px; border: 1px solid var(--line);
  color: var(--muted); background: #fbfcfd;
}
.badge.cat { color: var(--brand); border-color: #d3ddf7; background: #eef3fe; }
.badge.status-available { color: var(--ok); border-color: #cfe9d8; background: #ecf7f0; }
.badge.status-on_loan  { color: var(--warn); border-color: #f0e2c4; background: #fbf5e8; }
.badge.status-reserved { color: var(--warn); border-color: #f0e2c4; background: #fbf5e8; }
.badge.status-lost     { color: var(--danger); border-color: #f0cfcf; background: #fbeeee; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 6px; cursor: pointer;
  font-size: 0.9rem; font-weight: 600; padding: 9px 14px;
  border-radius: 10px; border: 1px solid var(--line);
  background: var(--card); color: var(--ink); text-decoration: none;
}
.btn:hover { border-color: #ccd3db; }
.btn-primary { background: var(--brand); color: var(--brand-ink); border-color: var(--brand); }
.btn-primary:hover { background: #2749b3; }
.btn-danger { color: var(--danger); border-color: #f0cfcf; }
.btn-sm { padding: 5px 10px; font-size: 0.82rem; }

/* ---------- cards / sections ---------- */
.panel {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 20px; margin: 20px 0;
}
.panel h2 { margin-top: 0; }

/* ---------- forms ---------- */
.form-grid { display: grid; gap: 12px; grid-template-columns: repeat(2, 1fr); }
.field { display: flex; flex-direction: column; gap: 4px; }
.field.full { grid-column: 1 / -1; }
.field label { font-size: 0.82rem; font-weight: 600; color: var(--muted); }
.field input, .field select, .field textarea {
  padding: 9px 11px; border: 1px solid var(--line); border-radius: 9px;
  font-size: 0.95rem; font-family: inherit; background: var(--card); color: var(--ink);
}
.field textarea { min-height: 70px; resize: vertical; }
.checkbox-row { display: flex; align-items: center; gap: 8px; }
.checkbox-row input { width: 16px; height: 16px; }

/* ---------- table ---------- */
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.03em; }
tr:hover td { background: #fafbfc; }

/* ---------- misc ---------- */
.notice {
  padding: 12px 14px; border-radius: 10px; font-size: 0.9rem; margin: 12px 0;
}
.notice.info    { background: #eef3fe; color: #24417f; border: 1px solid #d3ddf7; }
.notice.success { background: #ecf7f0; color: #1a6b3c; border: 1px solid #cfe9d8; }
.notice.error   { background: #fbeeee; color: #9a2b2b; border: 1px solid #f0cfcf; }
.empty { text-align: center; color: var(--muted); padding: 40px 20px; }
.mode-pill {
  font-size: 0.72rem; padding: 2px 8px; border-radius: 999px;
  background: #f0f2f5; color: var(--muted); border: 1px solid var(--line);
}
.row-actions { display: flex; gap: 6px; flex-wrap: wrap; }
.site-footer { text-align: center; color: var(--muted); font-size: 0.82rem; padding: 30px 0; }
.hidden { display: none !important; }

/* ---------- modal ---------- */
.overlay {
  position: fixed; inset: 0; z-index: 50;
  background: rgba(20, 27, 38, 0.55);
  display: flex; align-items: center; justify-content: center;
  padding: 20px; overflow-y: auto;
}
.modal {
  position: relative; background: var(--card); border-radius: 16px;
  box-shadow: 0 20px 50px rgba(16, 24, 40, 0.28);
  width: 100%; max-width: 560px; padding: 28px; margin: auto;
  animation: modal-in 0.14s ease-out;
}
@keyframes modal-in { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
.modal-close {
  position: absolute; top: 12px; right: 14px; border: none; background: none;
  font-size: 1.7rem; line-height: 1; color: var(--muted); cursor: pointer; padding: 4px;
}
.modal-close:hover { color: var(--ink); }
.modal-actions { margin-top: 22px; padding-top: 16px; border-top: 1px solid var(--line); }

.detail-title { margin: 0 30px 2px 0; font-size: 1.4rem; line-height: 1.25; }
.detail-byline { color: var(--muted); margin-bottom: 16px; }
.detail-badges { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 18px; }
.detail-grid { display: grid; grid-template-columns: auto 1fr; gap: 8px 18px; font-size: 0.92rem; }
.detail-grid dt { color: var(--muted); font-weight: 600; }
.detail-grid dd { margin: 0; }

/* ---------- pagination ---------- */
.pager {
  display: flex; flex-wrap: wrap; align-items: center; gap: 14px;
  margin: 22px 0 8px; padding-top: 16px; border-top: 1px solid var(--line);
}
.pager-nav { display: flex; align-items: center; gap: 12px; }
.pager .page-info { color: var(--muted); font-size: 0.86rem; white-space: nowrap; font-variant-numeric: tabular-nums; }
.pager .btn:disabled { opacity: 0.45; cursor: default; }
.page-size {
  margin-left: auto; display: inline-flex; align-items: center; gap: 8px;
  color: var(--muted); font-size: 0.88rem;
}
.page-size select {
  padding: 7px 10px; border: 1px solid var(--line); border-radius: 9px;
  background: var(--card); color: var(--ink); font-size: 0.9rem;
}

/* ---------- list view ---------- */
.list { display: block; }
.list-head, .list-row {
  display: grid;
  grid-template-columns: 3fr 2fr 1.6fr 0.7fr 1.1fr;
  gap: 12px; align-items: center; padding: 10px 14px;
}
.list-head {
  color: var(--muted); font-size: 0.74rem; text-transform: uppercase;
  letter-spacing: 0.03em; font-weight: 700; border-bottom: 1px solid var(--line);
}
.list-row {
  background: var(--card); border: 1px solid var(--line); border-top: none;
  cursor: pointer;
}
.list-row:first-of-type { border-top: 1px solid var(--line); }
.list-row:hover { background: #f7f9fc; }
.list-row:focus-visible { outline: 2px solid var(--brand); outline-offset: -2px; }
.list-row .lr-title { font-weight: 600; }
.list-row .lr-artist, .list-head .lr-artist { color: var(--muted); font-size: 0.9rem; }
.lr-year { color: var(--muted); font-size: 0.85rem; }

/* ---------- stat tiles ---------- */
.stat-tiles {
  display: grid; gap: 14px; margin: 24px 0;
  grid-template-columns: repeat(4, 1fr);
}
.stat-tile {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 18px 20px;
}
.stat-value { font-size: 1.8rem; font-weight: 700; line-height: 1.1; }
.stat-label { color: var(--muted); font-size: 0.85rem; margin-top: 4px; }

/* ---------- donut chart ---------- */
.chart-wrap { display: flex; flex-wrap: wrap; gap: 28px; align-items: center; }
.donut-col { position: relative; width: 220px; height: 220px; flex: 0 0 auto; }
#donut { width: 220px; height: 220px; }
.donut-center {
  position: absolute; inset: 0; display: flex; flex-direction: column;
  align-items: center; justify-content: center; pointer-events: none;
}
.donut-center strong { font-size: 1.7rem; }
.donut-center span { color: var(--muted); font-size: 0.82rem; }
.legend { list-style: none; margin: 0; padding: 0; flex: 1 1 240px; }
.legend li { display: flex; align-items: center; gap: 10px; padding: 6px 0; font-size: 0.92rem; }
.legend-dot { width: 12px; height: 12px; border-radius: 3px; flex: 0 0 auto; }
.legend-name { flex: 1; }
.legend-val { color: var(--muted); font-variant-numeric: tabular-nums; }

/* ---------- bars ---------- */
.bars { display: flex; flex-direction: column; gap: 8px; }
.bar-row { display: grid; grid-template-columns: 200px 1fr auto; gap: 12px; align-items: center; }
.bar-label { font-size: 0.88rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.bar-track { background: #eef0f3; border-radius: 6px; height: 14px; overflow: hidden; }
.bar-fill { height: 100%; border-radius: 6px; min-width: 2px; }
.bar-val { color: var(--muted); font-size: 0.82rem; font-variant-numeric: tabular-nums; white-space: nowrap; }

@media (max-width: 720px) {
  .stat-tiles { grid-template-columns: repeat(2, 1fr); }
  .list-head { display: none; }
  .list-row { grid-template-columns: 1fr auto; grid-auto-rows: min-content; row-gap: 4px; }
  .list-row .lr-artist { grid-column: 1; }
  .list-row .lr-cat { grid-column: 2; grid-row: 1; text-align: right; }
  .list-row .lr-year { display: none; }
  .list-row .lr-avail { grid-column: 2; text-align: right; }
  .bar-row { grid-template-columns: 120px 1fr auto; }
}

@media (max-width: 620px) {
  .form-grid { grid-template-columns: 1fr; }
  .site-header .container { flex-direction: column; align-items: flex-start; }
  .header-links a { margin-left: 0; margin-right: 16px; }
}