html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: #8fd8ff;
  font-family: sans-serif;
}
canvas { display: block; }
#hud {
  position: fixed;
  top: 8px;
  left: 12px;
  margin: 0;
  padding: 6px 12px;
  border-radius: 10px;
  background: rgba(0, 0, 0, 0.45);
  color: #fff;
  font-size: 16px;
}
#banner {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.55);
  color: #fff;
  text-align: center;
}
#banner[hidden] { display: none; }
#banner p { font-size: 24px; }