* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial,
    sans-serif;
  background-color: #f5f5f5;
  color: #333;
  min-height: 100vh;
}

header {
  background-color: #1a5f7a;
  color: white;
  padding: 1rem;
  text-align: center;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

header h1 {
  font-size: 1.5rem;
  font-weight: 600;
}

main {
  display: flex;
  flex-direction: column;
  min-height: calc(100vh - 60px);
}

.sidebar {
  background-color: white;
  padding: 1rem;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.control-group {
  margin-bottom: 1rem;
}

.control-group label {
  display: block;
  font-weight: 500;
  margin-bottom: 0.5rem;
  color: #555;
}

.control-group select {
  width: 100%;
  padding: 0.5rem;
  border: 1px solid #ddd;
  border-radius: 4px;
  font-size: 1rem;
  background-color: white;
}

.calendar-container {
  background-color: #fafafa;
  border: 1px solid #eee;
  border-radius: 8px;
  padding: 0.5rem;
}

.calendar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}

.calendar-header button {
  background: none;
  border: 1px solid #ddd;
  border-radius: 4px;
  padding: 0.25rem 0.75rem;
  cursor: pointer;
  font-size: 1rem;
}

.calendar-header button:hover {
  background-color: #eee;
}

#month-year {
  font-weight: 600;
  font-size: 0.9rem;
}

.calendar-weekdays {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  text-align: center;
  font-size: 0.75rem;
  color: #888;
  margin-bottom: 0.25rem;
}

.calendar-days {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 2px;
}

.calendar-day {
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  border-radius: 50%;
  cursor: pointer;
  transition: background-color 0.2s;
}

.calendar-day:hover {
  background-color: #e0e0e0;
}

.calendar-day.other-month {
  color: #ccc;
}

.calendar-day.has-track {
  background-color: #4caf50;
  color: white;
  font-weight: 600;
}

.calendar-day.has-track:hover {
  background-color: #43a047;
}

.calendar-day.selected {
  background-color: #1a5f7a;
  color: white;
}

.content {
  flex: 1;
  padding: 1rem;
  background-color: white;
}

#track-info {
  text-align: center;
  color: #888;
  padding: 2rem;
}

/* Tablet and desktop */
@media (min-width: 768px) {
  main {
    flex-direction: row;
  }

  .sidebar {
    width: 280px;
    flex-shrink: 0;
    border-right: 1px solid #eee;
  }

  .content {
    flex: 1;
  }

  header h1 {
    font-size: 1.75rem;
  }
}