body {
    margin: 0;
    padding: 0;
  }
  .banner {
    width: 100%;
    height: 120px;
    background-color: #F0F0F0;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
  }
  .logo {
    width: 100px;
  }
  .welcome {
    text-align: right;
    color: #000;
  }
  .sidebar {
    position: fixed;
    left: -250px;
    top: 0;
    height: 100%;
    width: 250px;
    background-color: #F0F0F0;
    transition: left 0.3s ease;
  }
  .sidebar.show {
    left: 0;
  }
  .sidebar ul {
    list-style: none;
    padding: 20px;
  }
  .sidebar ul li {
    margin-bottom: 10px;
    text-decoration: none;
  }
  .content {
    margin-top: 120px;
    display: flex;
    justify-content: center;
    align-items: center;
    height: calc(100vh - 120px);
  }
  .box {
    width: 200px;
    height: 200px;
    background-color: #ccc;
    margin: 20px;
  }