I'm running the Arduino IDE on my Surface 4 and everything is absolutely tiny. I can't find a way to zoom in and this is rendering the IDE useless to me. I assume this is because the IDE might use pixel scaling and the screen is pretty high resolution, however I am not sure of this.
Just go to File>Preferences and change the zoom. This will mostly fix the problem, though the top menu and start screen will still be tiny. This can be hard to do however due to the fact that the preferences menu is very small before the changes have taken effect.
Sorry for posting before really looking for all the solutions. I just assumed there was no zoom option because I couldn't read the menu.