#background-canvas {
  position: fixed !important;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;

  /* ここが本命：earth.pngを背景にする */
  background-image: url("https://re-provista.com/wp-content/uploads/2026/02/earth.png");
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;

  pointer-events: none;
  overflow: hidden;
}

/* canvasの余計な隙間対策 */
canvas {
  display: block;
}