Browsers get more and more standardised every day and most of them share the same shortcuts by now, such as how to reset the zoom level. Zoom can be reset by pressing ctrl + 0 on windows, and command + 0 on Mac. That is a zero, not an O.
This is often used when you somehow manage to accidentally zoom in, as a lot of webpages do not handle zoom well. I have had many online meetings with clients where their version of the site looks horrible. I often first ask them to reset their zoom level. Years back I also asked them to clear their cache.
I hope you enjoyed this tip, please let me know in the comments if you did! :)