:root {
  --bg: #f7f8fb;
  --text: #1f2937;
  --muted: #6b7280;
  --good: #dcfce7;
  --bad: #fee2e2;
  --na: #e5e7eb;
  --card: #ffffff;
  --border: #d1d5db;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
}
.topbar {
  position: sticky;
  top: 0;
  background: var(--card);
  padding: 12px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  z-index: 10;
}
.topbar h1 { font-size: 1rem; margin: 0; }
.topbar button { padding: 8px 10px; border-radius: 8px; border: 1px solid var(--border); background: white; }

#calendar {
  max-width: 780px;
  margin: 0 auto;
  padding: 8px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.month {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}
.month h2 {
  margin: 0;
  padding: 10px 12px;
  font-size: 1rem;
  border-bottom: 1px solid var(--border);
}
.weekdays,
.grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
}
.weekdays div {
  text-align: center;
  font-size: 0.75rem;
  color: var(--muted);
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
}
.cell {
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  min-height: 74px;
  padding: 6px;
  font-size: 0.78rem;
}
.cell:nth-child(7n) { border-right: none; }
.cell .day { font-weight: 600; margin-bottom: 3px; }
.cell .mer { font-size: 0.75rem; color: #374151; }
.cell.empty { background: #fafafa; }
.cell.good { background: var(--good); }
.cell.bad { background: var(--bad); }
.cell.na { background: var(--na); }