Firefox has a zoom option that helps with reading those tiny furigana with even tinier rendaku. It's one change in the configuration to make it mimic a touch device's zoom but while using a mouse.
about:config -> mousewheel*action$ -> choose one of alt, control, or shift -> change its value to 5. While holding your choice of alt, control, or shift, it now zooms like a touch device.
(I only know because of this person's comment: reddit link)
And because Firefox has it, I bet the others do too.
--- Screenshot
In this picture, I've modified mousewheel.with_alt.action to have a value of 5.
--- Example uses
- To figure out whether a tiny furigana says ぴ or び, but without screwing up page structure with the normal zoom.
- To actually see the strokes on those tiny kanji.