Maybe it is the properties that are good and the selectors that are bad. One could point to a trend in the last 15 years of HTML and CSS being tuned up as an application platform.
Agreed on grid layout and flexbox. Took them a while to "fully" land, but now that they're here, they also represent a good model for visual design tools to work with as output.
I'd point out the grid layout and flexbox as being features ideal for application work and https://www.w3.org/TR/2011/WD-html5-20110405/forms.html#form... is practically a love letter for applications.