body {
    margin: 0;
    font-family: "Segoe UI", sans-serif;
    background: #1e88e5;
    color: white;
    text-align: center;
  }
  
  .logo {
    margin-top: 30px;
    font-size: 48px;
    color: #bbdefb;
    text-shadow: 0 4px 10px rgba(0,0,0,0.3);
  }
  
  .menu button,
  .section button {
    background: #ff9800;
    border: none;
    padding: 14px 28px;
    margin: 10px;
    font-size: 16px;
    border-radius: 10px;
    cursor: pointer;
    color: white;
  }
  
  .menu button:hover,
  .section button:hover {
    background: #fb8c00;
  }
  
  .section {
    margin-top: 20px;
  }
  
  .hidden {
    display: none;
  }
  
  #upload {
    background: white;
    padding: 12px;
    border-radius: 8px;
  }
  
  #presetSection img {
    width: 180px;
    margin: 10px;
    border-radius: 10px;
    cursor: pointer;
    border: 3px solid transparent;
  }
  
  #presetSection img:hover {
    border-color: #ff9800;
  }
  
  #puzzle {
    margin: 30px auto;
    display: grid;
    gap: 2px;
  }
  
  .piece {
    background-size: 100% 100%;
    border: 1px solid rgba(255,255,255,0.5);
    cursor: grab;
  }