*{box-sizing:border-box}
html,body{height:100%}
body{
  background:#000;
  color:#fff;
  font-family: "Courier New", Courier, monospace;
  display:flex;
  align-items:center;
  justify-content:center;
  flex-direction:column;
  gap:12px;
  margin:0;
}
canvas{
  image-rendering: pixelated;
  width:640px; /* 160 * 4 */
  height:480px;
  border:6px solid #fff;
  background:#000;
  display:block;
  box-shadow:0 0 20px rgba(255,255,255,0.05);
}
#ui{ text-align:center; }
h1{margin:0;font-size:20px;letter-spacing:4px;}
.hint{margin:6px 0 0 0;opacity:0.85}
#score{position:fixed;left:12px;top:12px;font-weight:700;}

/* small retro particle */
.pulse{animation:pulse 0.9s linear infinite}
@keyframes pulse{50%{opacity:0.3}}