It's Ctrl+"=" for me, although Ctrl+Shift+"=" aka Ctrl+"+" also works, and Ctrl+ScrollUp as well. Browsers also seem to have an option to increase font size onl

It's Ctrl+"=" for me, although Ctrl+Shift+"=" aka Ctrl+"+" also works, and Ctrl+ScrollUp as well. Browsers also seem to have an option to increase font size only, instead of all content. In Firefox, you just have to enable a checkbox in the menu bar at View -> Zoom -> Zoom Text Only. The menu bar, if hidden, can be accessed by pressing (and releasing) left Alt.