Traffic lights in Power Bi which work also for totals

How to make traffic light in table visual which works also for totals? Let's say our KPI is some sort of a ratio or a share like GDP per capita by countries, or the difference from the budget by stores. It is interesting to have traffic lights for individual categories but it would be even more interesting to have a traffic light for summary of all categories.

I followed and example shown here: The idea is based on adding a DAX measure:

TrafficLight = UNICHAR(11044)

And then we set up conditional formatting for traffic lights based on other column or measure. But the conditional formatting seems not to affect totals. How to have a traffic light which also shows red, yellow, green color for totals?

Edit. Seems to be a dream feature you can vote for. Please do vote for it!

https://ideas.powerbi.com/forums/265200-power-bi-ideas/suggestions/17401381-conditional-formatting-for-total-and-subtotals-in

Since the April 2020 PBI update this is finally possible:

https://powerbi.microsoft.com/en-us/blog/power-bi-desktop-april-2020-feature-summary/#_Conditional_formatting