body {
    margin: 0;
    font-family: Arial;
    display: flex;
    height: 100vh;
  }
  
  .app {
    display: flex;
    width: 100%;
  }
  
  /* Sidebar */
  .sidebar {
    width: 200px;
    background: #2c2c3a;
    color: white;
    padding: 10px;
  }
  
  .sidebar button {
    width: 100%;
    margin: 5px 0;
    padding: 10px;
    border: none;
    background: #6c5ce7;
    color: white;
    cursor: pointer;
  }
  
  /* Main */
  .main {
    flex: 1;
    padding: 20px;
  }
  
  .section {
    display: block;
  }
  
  .hidden {
    display: none;
  }
  
  /* Tasks & Habits */
  li {
    background: #eee;
    padding: 10px;
    margin: 5px 0;
    display: flex;
    justify-content: space-between;
  }
  
  .done {
    text-decoration: line-through;
    color: gray;
  }
  
  /* Notes */
  textarea {
    width: 100%;
    height: 200px;
  }
  
  /* Dark mode */
  .dark {
    background: #121212;
    color: white;
  }
  
  .dark .sidebar {
    background: #1e1e1e;
  }
  
  .dark li {
    background: #333;
  }