static S hstyle_matrixBackground() {
  ret hstyle([[
    a { color: white; }
    body {
      color: white;
      background: linear-gradient(
        rgba(0, 0, 0, 0.85), 
        rgba(0, 0, 0, 0.85)
      ), url(http://eyeocr.sourceforge.net/filestore/filestore.php?cmd=serve&file=blob_1013081&contentType=image/jpeg)
    }
  ]]);
}