Bar Charts | Google Developers 03.05.2021 · The first two bars each use a specific color (the first with an English name, the second with an RGB value). No opacity was chosen, so the default of 1.0 (fully opaque) is used; that's why the second bar obscures the gridline behind it. In the third bar, an opacity of 0.2 is used, revealing the gridline. In the fourth bar, three style attributes are used: stroke-color and …