#pileup {
  position: absolute;
  left: 10px;
  right: 10px;
  top: 10px;
  bottom: 10px;
}
.track-label {
  flex: 0 0 150px;  /* fixed-width track labels */
  text-align: right;
  font-size: 0.9em;
  position: relative;  /* make this an offset parent for positioning the label. */
}