From the author "Photon has its own HTML5 inspired canvas drawing engine using Cairo underneath".

That means it should render nicely at any resolution, the author says, "resolution independent and allows for HDPI displays".

But using Cairo means it should not have a good performance at high resolutions. I have yet to find a fork of Cairo GPU accelerated that supports all the API. So it may fit the bill if you are coding a simple interface, but it will be too slow to render at 60FPS and at high resolution.

What comes closest for me is Dear ImGui, but I never saw an interface with those nicely rendered buttons in real-time done with Dear ImGui.