/* source: problem\problem9.htm style block 1 */
body { font-family: Arial, sans-serif; margin: 20px; text-align: center; }
    img { width: min(320px, 80vw); height: auto; margin: 0 auto 20px; display: block; }
    canvas { margin: 20px 0; border: 1px solid #ccc; background-color: #fff; }
    button { margin: 10px 5px; padding: 10px 20px; font-size: 16px; background-color: #4CAF50; color: white; border: none; border-radius: 5px; cursor: pointer; }
    button:hover { background-color: #45a049; }
    #solution { display: none; margin-top: 20px; padding: 15px; background-color: #eef; border-radius: 8px; }