body {
  font-family: Verdana, sans-serif;
  margin: 0;
  padding: 0;
}

.calendar {
  width: 100%;
  max-width: 600px;
  margin: 0 auto;
}

.month ul {
  list-style-type: none;
  margin: 0;
  padding: 10px;
  background: #1abc9c;
  color: white;
  text-align: center;
}

.month ul li {
  display: inline-block;
  font-size: 18px;
  padding: 5px 10px;
}

.month .prev, .month .next {
  cursor: pointer;
}

.weekdays, .days {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 5px;
  text-align: center;
}

.weekdays div {
  background: #ddd;
  padding: 10px;
  font-weight: bold;
}

.days div {
  padding: 10px;
  background: #f9f9f9;
  border: 1px solid #ddd;
}

.days div:hover {
  background: #e0e0e0;
  cursor: pointer;
}