We aren't listening for devicePixelRatio changes (and should be).
To reproduce, open up a sim that uses WebGL (natural-selection, neuron, etc.) or set ?rootRenderer=canvas, and:
- Load the simulation on a lower-DPI monitor
- Move the browser to a higher-DPI monitor
- The simulation's Canvas/WebGL parts will be blurrier than if you reload (or load from the start on the high-DPI monitor)
Loaded high-DPI on high-DPI:

Loaded low-DPI on high-DPI:

It looks like this is possible with matchMedia, example in https://developer.mozilla.org/en-US/docs/Web/API/Window/devicePixelRatio.