Doesn’t mean you need electron to fix it, it can be done with a native UI. But bitmapped skins are generally not used anymore for a reason.
Yes, but with what price?
We (people outside of Microsoft, Apple and Google) cannot afford UIs nailed down to pixel grids and particular trends.
Years ago it was Skeumorphism, then it was flat UI as Metro, today people started speaking about Skeumorphism again. CSS is just a convenient tool to follow the trends.
And "yes" it "doesn’t mean you need electron" as there are other options :)
Take Sciter and forget about UI problems and "resource hogs" for years to come. HTML/CSS will be with us together with the Internet. And so are UI developers that can take care about it. And C++ developers in case you will need to fix something critical inside the Sciter.
In 90s this was solved by using "skins" which were actually drawn in graphics programs and then spliced and edited in some proprietary editor and/or positioned by hand crafted config file.
See https://winampheritage.com/skin for example. You can't go more original than these. :-D
I don't see a point why you would need web library for this.