I can reproduce the iPad issue. The main issue there is that the BBS logo is too wide, and it doesn’t shrink properly. That should be the first thing to fix.
After that is fixed, you’ll need to manually switch to the mobile view, because iPads send a regular Safari user agent name, which means that Discourse can’t detect it as a mobile device, and thus, will be delivering a desktop layout by default, even on that window width. (You can use the DiscourseHub app instead of Safari, that will deliver a mobile site by default on smaller window sizes on iPads.)