html, body {
  height: 100%;
  margin: 0;
  padding: 0;
  background: #000; /* page background = black */
  color: #fff;
}
canvas {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
}
/* QR visual fallback (if used elsewhere) */
#qrcode {
  display: inline-block;
  padding: 8px;
  border: 2px solid #333;
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
}

/* visible enable-compass button over the black canvas */
#enableCompassBtn {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 9999;
  padding: 10px 14px;
  background: linear-gradient(180deg,#fff,#e6e6e6);
  color: #000;
  border: 1px solid rgba(0,0,0,0.2);
  border-radius: 8px;
  font-weight: 600;
  font-size: 14px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.45);
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

/* make it more visible when pressed/touched */
#enableCompassBtn:active,
#enableCompassBtn:focus {
  outline: none;
  transform: translateY(1px);
  box-shadow: 0 2px 8px rgba(0,0,0,0.5);
}