body {
  font-family: Arial, sans-serif;
  background: #f0f0f0;
  margin: 0;
  padding: 0;
}

header {
  text-align: center;
  background: #333;
  color: white;
  padding: 1rem;
}

.nav {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
}

.nav button {
  padding: 0.5rem 1rem;
  background: #555;
  color: white;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  border-radius: 5px;
}

.calendar {
  max-width: 800px;
  margin: 2rem auto;
  background: white;
  box-shadow: 0 2px 5px rgba(0,0,0,0.2);
  padding: 1rem;
  border-radius: 8px;
}

.day-names, .days-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  text-align: center;
}

.day-names div {
  font-weight: bold;
  padding: 0.5rem 0;
  background: #eee;
  border-bottom: 1px solid #ccc;
}

.days-grid div {
  padding: 1rem;
  border: 1px solid #eee;
  min-height: 60px;
}