style.css

* {
    box-sizing: border-box;
  }
  
  body {
    background-color: #0095dd;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    font-family: Arial, Helvetica, sans-serif;
    min-height: 100vh;
    margin: 0;
  }
  
  h1 {
    font-size: 45px;
    color: #fff;
  }
  
  canvas {
    background: #f0f0f0;
    display: block;
    border-radius: 5px;
  }
  
  .btn {
    cursor: pointer;
    border: 0;
    padding: 10px 20px;
    background: #000;
    color: #fff;
    border-radius: 5px;
  }
  
  .btn:focus {
    outline: 0;
  }
  
  .btn:hover {
    background: #222;
  }
  
  .btn:active {
    transform: scale(0.98);
  }
  
  .rules-btn {
    position: absolute;
    top: 30px;
    left: 30px;
  }
  
  .rules {
    position: absolute;
    top: 0;
    left: 0;
    background: #333;
    color: #fff;
    min-height: 100vh;
    width: 400px;
    padding: 20px;
    line-height: 1.5;
    transform: translateX(-400px);
    transition: transform 1s ease-in-out;
  }
  
  .rules.show {
    transform: translateX(0);
  }