/* --- Layout --- */
html,body{
  height:100%;
  margin:0;
  font-family: Segoe UI, Arial, sans-serif;
  background:#f3f3f3;
}

.container{
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:16px;
  padding:20px;
}

/* --- Canvas --- */
canvas{
  background:#fff;
  display:block;
  position:fixed;
  left:0;
  top:0;
  width:100vw;
  height:100vh;
  max-width:none;
  max-height:none;
  border:0;
}