message: Spinner: supported placement in PanelHeader
diff: stroke: var(--accent);
  }
  + .PanelHeader--ios .Spinner__self {
  + fill: currentColor;
  + }
  +
  + .PanelHeader--android .Spinner__self {
  + stroke: currentColor;
  + }
  +
  .ScreenSpinner--android .Spinner__self {
  stroke: var(--white);
  }
  