@C4thie
Google complains all the time because it's not mobile friendly. Things too close together and too small illegible font. You try to change these things in your styles. But styles based on prosilver are always criticised by google somewhere.
In this day and age, everything has to be mobile-friendly. Google only indexes pages on mobile.
Changes are important, however in my opinion drastic changes are not good, because overall it shows the users that it's not worth to put the effort. And risk more time wasted. It breaks trust to the project, because it shows it as very unstable and chaotic.
phpBB cannot avoid a completely new style structure.
It also works good enough on phones. However if someone really want modern solutions then it's not worth building "mobile first" forums. It's not 2010+ anymore. Nowadays mobile users are using app's. So if you want to build something modern for mobile users then create app. Rather than wasting time on building forum for mobiles, cause no one is going to use it anyway. Who's using yt, twitch, reddit or discord via browser? (on mobile). Almost nobody. People use apps nowadays and that's the future for mobiles. Apps. Not websites via browsers...
Many users visit the forums with a computer and not with mobile devices.
I hate the YT app on the phone. I always visit YT with the browser.