* {
      box-sizing: border-box;
    }

    body {
      font-family: Arial, sans-serif;
      background: #f0f4f8;
      margin: 0;
      padding: 2rem;
      display: flex;
      justify-content: center;
    }

    .container {
      background: #fff;
      padding: 2rem;
      border-radius: 12px;
      box-shadow: 0 4px 8px rgba(0,0,0,0.1);
      width: 100%;
      max-width: 400px;
    }

    h1 {
      text-align: center;
      color: #333;
    }

    form {
      display: flex;
      gap: 0.5rem;
      margin-bottom: 1rem;
    }

    input[type="text"] {
      flex: 1;
      padding: 0.5rem;
      border: 1px solid #ccc;
      border-radius: 6px;
    }

    button {
      padding: 0.5rem 1rem;
      border: none;
      background: #007bff;
      color: white;
      border-radius: 6px;
      cursor: pointer;
    }

    ul {
      list-style: none;
      padding: 0;
      margin: 0;
    }

    li {
      display: flex;
      justify-content: space-between;
      align-items: center;
      background: #f9f9f9;
      padding: 0.5rem;
      margin-bottom: 0.5rem;
      border-radius: 6px;
    }

    li.completed span {
      text-decoration: line-through;
      color: gray;
    }

    .actions {
      display: flex;
      gap: 0.5rem;
    }

    .actions button {
      background: none;
      border: none;
      cursor: pointer;
      color: #007bff;
    }

    .actions button.delete {
      color: crimson;
    }