How to set points color at loading status.

[xiaozhah]

When loading the dataset, the points are drawn in gray. But I can't search any code to describe the color of points at loading. Could it be changed?

In index.html, even background color is black transparent(dark mode), the points in still unseen.

      #chart-container > div {
        position: absolute;
        top: 0; bottom: 0; right: 170; left: 170;
        text-align: middle;
        vertical-align: middle;
        background-color: rgba(0 ,0, 0, 0);
      }