* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family:Arial, Helvetica, sans-serif;
  }
  
  .container {
    display: flex;
    height: 100vh;
  }
  
  .sidebar {
    width: 220px;
    background-color: #ffffff;
    padding: 20px;
    position: fixed;
    height: 100%;

  }
  .sidebar ul { 
    list-style-type: none; 
    padding: 0; 
    margin: 0;
}
  
  .sidebar a {
    color: black;
    text-decoration: none;
    font-size: 18px;
    display: block;
  }
  
  
  .main-content {
    margin-left: 220px;
    padding: 40px;
    flex-grow: 1;
  }
  
  @media (max-width: 900px) {
    .sidebar {
      width: calc(50% - 20px);
    }
  }
  
  @media (max-width: 600px) {
    .sidebar {
      width: 100%;
    }
  }