* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  list-style: none;
}

body {
  font: 100%/1.5 system, -apple-system, '.SFNSText-Regular', 'San Francisco',
    'Roboto', 'Segoe UI', 'Helvetica Neue', 'Lucida Grande', sans-serif;
  background: #fff;
  color: #000;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}

.calendar {
  --gap: 0.5rem;
  --radius: 0.6rem;
  --muted: #98a2b3;
  --ring: #2563eb;
  --sel-bg: #2563eb15;
  --today: #16a34a;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial,
    sans-serif;
  max-width: 340px;
}
.cal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--gap);
  margin-bottom: var(--gap);
}
.cal-title {
  font-weight: 600;
  text-transform: capitalize;
}
.cal-btn {
  padding: 0.35rem 0.6rem;
  border-radius: var(--radius);
  border: 1px solid #e5e7eb;
  background: #fff;
  cursor: pointer;
}
.cal-btn:hover {
  background: #f8fafc;
}
.cal-week-header {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 2px;
  margin-bottom: 2px;
  font-size: 0.85rem;
  color: var(--muted);
}
.cal-weekday {
  text-align: center;
  padding: 0.25rem 0;
}
.cal-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 2px;
}
.cal-cell {
  position: relative;
  padding: 0.6rem 0;
  text-align: center;
  border-radius: var(--radius);
  border: 1px solid #f1f5f9;
  background: #fff;
  cursor: pointer;
}
.cal-cell:focus {
  outline: 2px solid var(--ring);
  outline-offset: 2px;
  z-index: 1;
}
.cal-cell.is-out {
  color: var(--muted);
  background: #fafafa;
}
.cal-cell.is-today {
  box-shadow: inset 0 0 0 2px var(--today);
}
.cal-cell.is-selected {
  background: var(--sel-bg);
  border-color: #c7d2fe;
}