body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f4f4f4;
  }
  
  body * {
    box-sizing: border-box;
  }
  
  .container {
    max-width: 600px;
    margin: 0 auto;
    background: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  }
  
  h1 {
    margin-top: 0;
    color: #333;
  }
  
  #todoInput {
    width: 70%;
    padding: 10px;
    font-size: 16px;
    border: 1px solid #ddd;
    border-radius: 4px;
  }
  
  #addBtn {
    width: 25%;
    padding: 10px;
    font-size: 16px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
  }
  
  #addBtn:hover {
    background-color: #45a049;
  }
  
  #todoList {
    list-style: none;
    padding: 0;
    margin-top: 20px;
  }
  
  #todoList li {
    padding: 12px;
    background-color: #f9f9f9;
    margin-bottom: 8px;
    border-radius: 4px;
    border-left: 4px solid #4CAF50;
  }