superset/caravel/assets/visualizations/big_number.css

.big_number g.axis text,
.big_number_total g.axis text {
  font-size: 10px;
  font-weight: normal;
  color: gray;
  fill: gray;
  text-anchor: middle;
  alignment-baseline: middle;
  font-weight: none;
}

.big_number text.big,
.big_number_total text.big{
  stroke: black;
  text-anchor: middle;
  fill: black;
}

.big_number g.tick line,
.big_number_total g.tick line{
  stroke-width: 1px;
  stroke: grey;
}

.big_number .domain,
.big_number_total .domain{
  fill: none;
  stroke: black;
  stroke-width: 1;
}