:root {
  --bg: #f4f6f9;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --primary: #2563eb;
  --primary-ink: #ffffff;
  --danger: #dc2626;
  --weekend: #fafafa;
  --today: #fff7d6;
  --radius: 10px;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.5 "Noto Sans TC", "Microsoft JhengHei", "PingFang TC", system-ui, sans-serif;
}

a { color: var(--primary); }

/* ---------- 頂部列 ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 20px;
  padding: 10px 20px;
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.brand { font-size: 18px; font-weight: 700; }
.brand a { color: inherit; text-decoration: none; }
.brand small { font-weight: 400; color: var(--muted); margin-left: 6px; }

.tabs { display: flex; flex-wrap: wrap; gap: 4px; flex: 1; }
.tabs button, .tabs a {
  border: 0;
  background: none;
  padding: 8px 14px;
  border-radius: 8px;
  font: inherit;
  color: var(--muted);
  cursor: pointer;
  text-decoration: none;
}
.tabs button:hover, .tabs a:hover { background: var(--bg); color: var(--text); }
.tabs button.active, .tabs a.active { background: #e8efff; color: var(--primary); font-weight: 600; }

/* 管理後台的第二排分頁 */
.subtabs {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--line);
}
.subtabs button {
  border: 0;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  background: none;
  padding: 8px 14px;
  font: inherit;
  color: var(--muted);
  cursor: pointer;
}
.subtabs button:hover { color: var(--text); }
.subtabs button.active { color: var(--primary); border-bottom-color: var(--primary); font-weight: 600; }
.count:not(:empty) {
  display: inline-block;
  min-width: 20px;
  padding: 0 6px;
  border-radius: 10px;
  background: var(--danger);
  color: #fff;
  font-size: 12px;
  text-align: center;
}

.user { display: flex; align-items: center; gap: 10px; margin-left: auto; }
.who small { margin-left: 6px; padding: 1px 6px; border-radius: 6px; background: var(--bg); color: var(--muted); font-size: 12px; }

main { max-width: 1200px; margin: 0 auto; padding: 20px; }

.tab { display: none; }
.tab.active { display: block; }

/* ---------- 元件 ---------- */
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin-bottom: 14px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: 7px 14px;
  border: 1px solid var(--primary);
  border-radius: 8px;
  background: var(--primary);
  color: var(--primary-ink);
  font: inherit;
  cursor: pointer;
  white-space: nowrap;
}
.btn:disabled { opacity: .5; cursor: default; }
.btn.ghost { background: transparent; color: var(--primary); border-color: var(--line); }
.btn.ghost:hover:not(:disabled) { border-color: var(--primary); }
.btn.danger { background: var(--danger); border-color: var(--danger); color: #fff; }
.btn.danger.ghost { background: transparent; color: var(--danger); border-color: var(--line); }
.btn.danger.ghost:hover { border-color: var(--danger); }
.btn.small { padding: 3px 8px; font-size: 13px; }

input, select, textarea {
  font: inherit;
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--text);
  max-width: 100%;
}
input:focus, select:focus, textarea:focus { outline: 2px solid #bfd3ff; border-color: var(--primary); }

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}
.toolbar h2 { margin: 0; min-width: 150px; text-align: center; font-size: 20px; }
.spacer { flex: 1; }

.hint, .muted { color: var(--muted); font-size: 14px; }
#applyPreview { min-height: 1.5em; margin-bottom: 10px; }

.badge {
  display: inline-block;
  padding: 1px 8px;
  border-radius: 10px;
  font-size: 12px;
  font-weight: 600;
  vertical-align: middle;
}
.badge.pending { background: #fef3c7; color: #92400e; }
.badge.approved { background: #dcfce7; color: #166534; }
.badge.rejected { background: #fee2e2; color: #991b1b; }
.badge.cancelled { background: #e5e7eb; color: #4b5563; }

/* ---------- 月曆 ---------- */
.calendar {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr)) repeat(2, minmax(0, .7fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
.cal-head {
  background: #f9fafb;
  padding: 6px;
  text-align: center;
  font-weight: 600;
  color: var(--muted);
}
.cal-cell {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 3px;
  min-height: 104px;
  padding: 6px;
  background: var(--card);
  border: 0;
  font: inherit;
  text-align: left;
  cursor: pointer;
  overflow: hidden;
}
.cal-cell:hover { background: #f0f5ff; }
.cal-cell.empty { cursor: default; background: #fbfbfc; }
.cal-cell.weekend, .cal-head.weekend { background: var(--weekend); }
.cal-cell.today { background: var(--today); }
.day-num { font-weight: 600; font-size: 14px; }
.cal-cell.today .day-num { color: var(--primary); }

.chip {
  display: block;
  padding: 1px 6px;
  border-left: 3px solid var(--c);
  border-radius: 4px;
  background: color-mix(in srgb, var(--c) 12%, white);
  font-size: 12px;
  line-height: 1.5;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ---------- 對話框與表格 ---------- */
dialog {
  width: min(1100px, 96vw);
  max-height: 90vh;
  padding: 0;
  border: 0;
  border-radius: var(--radius);
  box-shadow: 0 20px 50px rgba(0, 0, 0, .25);
}
dialog::backdrop { background: rgba(15, 23, 42, .45); }
.dialog-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
}
.dialog-head h3 { margin: 0; }
dialog .table-wrap { padding: 12px 16px 16px; }

.table-wrap { overflow-x: auto; }
table { border-collapse: collapse; width: 100%; background: var(--card); }
th, td { border: 1px solid var(--line); padding: 6px 8px; vertical-align: top; }
th { background: #f9fafb; font-weight: 600; text-align: left; }
th small, td small { display: block; color: var(--muted); font-weight: 400; font-size: 12px; }
.nowrap { white-space: nowrap; }

table.grid th, table.grid td { text-align: center; min-width: 90px; }
table.grid thead th { text-align: center; }
table.grid tbody th, table.grid thead th:first-child { text-align: left; white-space: nowrap; width: 1%; min-width: 0; }
table.grid td.free { color: #cbd5e1; }
table.grid td.busy { background: color-mix(in srgb, var(--c) 14%, white); font-weight: 600; font-size: 13px; }

table.data td input:not([type="checkbox"]) { width: 100%; min-width: 90px; }

/* ---------- 表單 ---------- */
.form h2 { margin-top: 0; }
.field { display: flex; flex-direction: column; gap: 4px; margin-bottom: 14px; font-weight: 600; border: 0; padding: 0; }
.field legend { font-weight: 600; margin-bottom: 6px; padding: 0; }
.field input, .field select, .field textarea { font-weight: 400; }
.inline { display: inline-flex; align-items: center; gap: 4px; margin-right: 16px; font-weight: 400; }
.row { display: flex; flex-wrap: wrap; gap: 0 16px; align-items: flex-end; }
.row .field { flex: 1 1 200px; }
.actions { display: flex; gap: 10px; margin-bottom: 14px; }

.checks { display: flex; flex-wrap: wrap; gap: 6px; }
.check {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 5px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  font-weight: 400;
  cursor: pointer;
  user-select: none;
}
.check:has(input:checked) { border-color: var(--primary); background: #e8efff; }
.check small { color: var(--muted); font-size: 11px; margin-left: 2px; }
.checks.days { display: grid; grid-template-columns: repeat(auto-fill, minmax(56px, 1fr)); }

/* ---------- 清單 ---------- */
.list .item { display: flex; gap: 16px; align-items: flex-start; justify-content: space-between; }
.item-main > div { margin: 2px 0; }
.item-title { font-weight: 700; font-size: 16px; }
.item-actions { display: flex; gap: 8px; flex-shrink: 0; }

/* ---------- 提示 ---------- */
#toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translate(-50%, 20px);
  padding: 10px 18px;
  border-radius: 8px;
  background: #111827;
  color: #fff;
  opacity: 0;
  pointer-events: none;
  transition: .2s;
  z-index: 100;
  max-width: 90vw;
}
#toast.show { opacity: 1; transform: translate(-50%, 0); }
#toast.error { background: var(--danger); }

/* 月曆：教室圓點列 */
.legend { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 16px; margin: -4px 0 10px; font-size: 13px; }
.legend span { display: inline-flex; align-items: center; gap: 5px; }
.legend i { width: 11px; height: 11px; border-radius: 50%; }
.drow { display: grid; grid-template-columns: 3.4em 1fr; align-items: center; column-gap: 4px; font-size: 12px; line-height: 1.6; }
.drow .rn { color: var(--c); font-weight: 700; white-space: nowrap; overflow: hidden; }
.drow .dots { display: grid; grid-template-columns: repeat(var(--n), 1fr); justify-items: center; }
.drow b { width: min(11px, 100%); aspect-ratio: 1; border-radius: 50%; border: 1.5px solid var(--c); opacity: .35; box-sizing: border-box; }
.drow b.on { background: var(--c); opacity: 1; }
.cal-cell .who { font-size: 11px; color: var(--muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

@media (max-width: 720px) {
  main { padding: 12px; }
  .topbar { padding: 8px 12px; }
  .tabs { order: 3; flex-basis: 100%; }
  .tabs button, .tabs a { white-space: nowrap; padding: 6px 10px; }
  .calendar { grid-template-columns: repeat(7, minmax(0, 1fr)); }
  .cal-cell { min-height: 72px; padding: 3px; }
  .chip { font-size: 10px; padding: 0 3px; }
  .drow { grid-template-columns: 1fr; font-size: 10px; }
  .drow b { border-width: 1px; }
  .list .item { flex-direction: column; }
}

.config-warning {
  padding: 10px 20px;
  background: #fef3c7;
  color: #92400e;
  border-bottom: 1px solid #fcd34d;
  font-size: 14px;
}
.config-warning code { background: #fde68a; padding: 0 4px; border-radius: 4px; }

.quick-periods { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; margin-bottom: 8px; font-weight: 400; }