/* Sidebar */
.sidebar {
  width: 250px;
  background-color: #f8f9fa;
  border-right: 1px solid #e0e0e0;
  padding: 1em;
  font-size: 0.95rem;
  font-family: Arial, sans-serif;
  box-shadow: 2px 0 5px rgba(0, 0, 0, 0.05);
}

.sidebar .menu-year {
  font-weight: 700;
  font-size: 1.2rem;
  color: #333333;
  margin-bottom: 1rem;
  border-bottom: 2px solid #2c3e50;
  padding-bottom: 0.5rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.sidebar nav ul {
  list-style: none;
  padding-left: 0;
}

.sidebar .menu-month {
  margin-bottom: 1rem;
  font-weight: 600;
  color: #555555;
}

.sidebar .menu-month ul {
  list-style: none;
  padding-left: 1rem;
  margin-top: 0.3rem;
}

.sidebar .menu-month li a {
  color: #2c3e50;
  text-decoration: none;
  display: block;
  padding: 0.2rem 0;
  transition: color 0.2s ease-in-out;
}

.sidebar .menu-month li a:hover {
  color: #1a73e8;
  text-decoration: underline;
}

/* Responsive sidebar */
@media (max-width: 900px) {
  .sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid #e0e0e0;
    margin-bottom: 1rem;
  }
}