body{height:100vh;display:flex;justify-content:center;align-items:center;padding:1rem}canvas{background:#000;position:relative;border-radius:.4rem}h2{font-size:1rem;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Open Sans,Helvetica Neue,sans-serif;font-weight:700}.box{display:block;border:1px solid green;position:absolute;top:0;left:0}button{outline:none;border:none;background:none;font-weight:700;text-decoration:underline;padding:1rem;cursor:pointer}.header{display:flex;justify-content:space-between}