Google Charts title font-size css flexible attribute?

Question

I'm working with Google Charts Combo Charts. According to documentation I can only specify titleTextStyle fontSize in pixels (px).

Instead, I want to control fontSize with css-like flexible attributes, e.g. (% or vw). The built-in options are not sufficient for a chart that needs to scale up to 4k (3840+px) and scale down to mobile (320-415px).

var options = {
    titleTextStyle: {
        fontName: <string>, // i.e. 'Times New Roman'
        fontSize: <number>, // e.g. 12 (px is implied)
    }
}

I have seen that it is possible to map css formatting to Google Charts Table Chart by using the cssClassNames option but I can't find any documentation for cssClassNames with Combo Chart. Search attempts have come up empty.

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