body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    margin: 0;
    padding: 0;
    transition: background-color 0.3s, color 0.3s;
  }
  
  .container {
    max-width: 600px;
    margin: auto;
    padding: 30px;
  }
  
  header {
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  .todo-input {
    display: flex;
    gap: 10px;
    margin-top: 20px;
  }
  
  input, button {
    padding: 10px;
    font-size: 16px;
  }
  
  .task-list {
    margin-top: 20px;
    padding: 0;
    list-style-type: none;
  }
  
  .task {
    background: #ffffff;
    margin-bottom: 10px;
    padding: 12px;
    border-left: 4px solid #2196F3;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: grab;
  }
  
  .task.completed {
    text-decoration: line-through;
    background-color: #d4edda;
  }
  
  button.complete-btn {
    background-color: #4CAF50;
    color: white;
    border: none;
    padding: 5px 10px;
    cursor: pointer;
  }
  
  button.delete-btn {
    background-color: #f44336;
    color: white;
    border: none;
    padding: 5px 10px;
    cursor: pointer;
  }
  
  .progress-container {
    margin-top: 20px;
    height: 10px;
    background: #ddd;
    border-radius: 5px;
  }
  
  #progress-bar {
    height: 100%;
    width: 0%;
    background: #4CAF50;
    transition: width 0.3s;
    border-radius: 5px;
  }
  
  /* Dark Mode */
  body.dark-mode {
    background-color: #121212;
    color: #f1f1f1;
  }
  
  body.dark-mode .task {
    background-color: #1f1f1f;
    color: #fff;
  }