* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  height: 100%;
  background: #0a0612;
  color: #c8b8e8;
  font-family: "Courier New", Courier, monospace;
}

#shell {
  min-height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 16px;
}

#game {
  image-rendering: pixelated;
  image-rendering: crisp-edges;
  border: 4px solid #3d2a6b;
  box-shadow: 0 0 40px rgba(120, 80, 255, 0.25);
  background: #000;
  max-width: 100%;
  outline: none;
}

#controls {
  display: flex;
  gap: 10px;
}

#fullscreen-btn {
  font-family: inherit;
  font-size: 13px;
  color: #c8b8e8;
  background: #1d1233;
  border: 2px solid #3d2a6b;
  border-radius: 6px;
  padding: 6px 14px;
  cursor: pointer;
}

#fullscreen-btn:hover {
  background: #2c1b4d;
  border-color: #7a5cff;
}

#hint {
  font-size: 12px;
  opacity: 0.75;
  text-align: center;
  max-width: 960px;
}

/* Fullscreen: fill the whole screen, keep 16:9, letterbox the rest */
#shell:fullscreen {
  background: #000;
  padding: 0;
  gap: 0;
}

#shell:fullscreen #game {
  height: 100vh;
  width: auto;
  max-width: 100vw;
  max-height: 100vh;
  border: none;
  box-shadow: none;
}

#shell:fullscreen #controls,
#shell:fullscreen #hint {
  display: none;
}