body {
    font-family: Arial, sans-serif;
    background-color: #f2f2f2;
    color: black;
    transition: background-color 0.5s ease;
  }

  h1 {
    text-align: center;
    margin-top: 40px;
  }

  body.dark-mode li {
    color: black;
  }

  #task-list {
    list-style-type: none;
    margin: 0;
    padding: 0;
  }

  #task-list li {
    background-color: #fff;
    border: 1px solid #ccc;
    border-radius: 5px;
    margin: 10px 0;
    padding: 10px;
    display: flex;
    justify-content: space-between;
  }

  #task-list li.completed {
    background-color: #ddd;
    text-decoration: line-through;
  }

  #task-list li button {
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 5px;
    padding: 5px;
    cursor: pointer;
  }

  #task-list li button:hover {
    background-color: #3e8e41;
  }

  #add-task-form {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-top: 20px;
  }

  #add-task-form label {
    font-weight: bold;
    margin-bottom: 10px;
  }

  #add-task-form input[type="text"] {
    padding: 5px;
    border-radius: 5px;
    border: none;
    margin-bottom: 10px;
  }

  #add-task-form button[type="submit"] {
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 5px;
    padding: 5px;
    cursor: pointer;
  }

  #add-task-form button[type="submit"]:hover {
    background-color: #3e8e41;
  }

  #clear-completed {
    display: block;
    margin: auto;
    background-color: #f44336;
    color: white;
    border: none;
    border-radius: 5px;
    padding: 5px;
    margin-top: 20px;
    cursor: pointer;
  }

  #clear-completed:hover {
    background-color: #d32f2f;
  }

  .dark-mode {
    background-color: #333;
    color: #fff;
  }

  #dark-mode-button {
    position: fixed;
    top: 10px;
    right: 10px;
    font-size: 24px;
    background: black;
    border: none;
    color: #fff;
    cursor: pointer;
  }

  #dark-mode-button.dark-mode {
    color: #f1c40f;
  }