/* 좌측 사이드바(header) */
.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: 180px;
    background-color: #333;
    color: #fff;
    padding: 2rem 1rem;
  }
  .sidebar h1 {
    font-size: 1.5rem;
    margin-bottom: 2rem;
  }
  .sidebar h1 a {
    color: #fff;
    text-decoration: none;
  }
  .sidebar nav ul {
    list-style: none;
    padding: 0;
  }
  .sidebar nav li {
    margin-bottom: 1rem;
  }
  .sidebar nav a {
    color: #fff;
    text-decoration: none;
    font-weight: bold;
    display: block;
  }
  .sidebar nav a:hover {
    text-decoration: underline;
  }