body{margin:0;font-family:Arial,sans-serif;text-align:center;background-color:#f0f0f0}h1{margin-top:20px}#container{display:flex;justify-content:center;align-items:center;margin-top:50px}#model1,#model2{width:400px;height:400px;margin:0 20px;background-color:#fff;border:1px solid #ccc}#furnace-container{width:800px;height:600px;margin:50px auto;background-color:#000;border:1px solid #ccc;position:relative}#hud{position:fixed;top:10px;left:10px;color:#fff;font-size:20px;text-align:left}#distance{margin-bottom:10px}#upgrade-button{background-color:#008CBA;padding:10px;border-radius:5px;cursor:pointer;display:inline-block;color:#fff}#upgrade-button:hover{background-color:#005f6b}#educational-content{position:fixed;bottom:10px;left:10px;color:#fff;font-size:18px;background-color:rgb(0 0 0 / .7);padding:15px;border-radius:5px;max-width:300px}