body {
        max-width: 850px;
        min-width: 600px;
        margin-right: auto;
        margin-left: auto;
        background: black;
      }
      h1, p {
        color: white;
      }
      .imageContainer {
        display: flex;
        flex-wrap: wrap;
        justify-content: space-between;
        margin-bottom: 20px;
      }
      .imageContainer img {
        width: 150px;
        cursor: pointer;
      }
      #puzzleContainer {
        width: 600px;
        height: 400px;
        border: 1px solid #ccc;
        overflow: hidden;
        margin-top: 20px;
        position: relative;
        background: white;
        margin-left: auto;
        margin-right: auto;
      }
      .puzzlePiece {
        border: 1px solid #000;
        box-sizing: border-box;
        cursor: pointer;
        position: absolute;
      }
      #navbar {
        overflow: hidden;
        background-color: #333;
      }
      #navbar a {
        float: left;
        display: block;
        color: #f2f2f2;
        text-align: center;
        padding: 14px 10px;
        text-decoration: none;
        font-size: 17px;
      }
      #navbar a:hover {
        background-color: silver;
        color: black;
      }
      #navbar a.active {
        background-color: orangered;
        color: white;
      }
      .sticky {
        position: fixed;
        top: 0;
        width: 100%;
      }