body {
  font-family: Arial;
  text-align: center;
  background: #f4f6f9;
}

.calendar-header {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 20px;
}

#calendar {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  max-width: 600px;
  margin: 20px auto;
  gap: 5px;
}

.day {
  padding: 15px;
  background: white;
  border-radius: 4px;
  cursor: pointer;
}

.day.booked {
  background: #ccc;
  cursor: not-allowed;
}

.day:hover:not(.booked) {
  background: #1e90ff;
  color: white;
}

.hidden {
  display: none;
}

form {
  max-width: 400px;
  margin: 20px auto;
}

input, textarea {
  width: 100%;
  margin: 10px 0;
  padding: 8px;
}