body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    background: var(--bg);
    color: var(--text);
    transition: all 0.3s;
  }
  
  :root {
    --bg: #f5f5f5;
    --text: #333;
    --card: #fff;
  }
  
  body.dark {
    --bg: #1e1e1e;
    --text: #eee;
    --card: #2a2a2a;
  }
  
  .container {
    width: 400px;
    background: var(--card);
    padding: 20px;
    border-radius: 12px;
    margin-top: 30px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
  }
  
  form, .controls {
    display: flex;
    gap: 6px;
    margin-bottom: 15px;
  }
  
  ul {
    list-style: none;
    padding: 0;
  }
  
  li {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--bg);
    padding: 8px;
    margin: 6px 0;
    border-radius: 6px;
    cursor: grab;
  }
  
  li.dragging {
    opacity: 0.5;
  }
  
  .task-text {
    flex-grow: 1;
  }
  
  .completed {
    text-decoration: line-through;
    color: gray;
  }
  
  button {
    cursor: pointer;
    padding: 5px 8px;
    border: none;
    border-radius: 5px;
    background: #3498db;
    color: #fff;
  }
  
  button:hover {
    background: #2980b9;
  }
  
  .editing input {
    flex-grow: 1;
  }