You should be easily able to add a banner using the magazine CSS. Though that's not being federated currently, I hope magazine CSS federation gets added in the future at least between kbin/mbin instances.
This should give you a banner above the threads section:
main > header {
/* Change both of these */
height: 100px;
background-image: url(https://i.imgur.com/zWuVa7U.png);
}
While this should give you one that also extends over the sidebar:
Changing the #middle to #header would put it above the kbin header (with the logo, the threads/microblog buttons, etc).
Community Engagement
There is an Active People section in the sidebar.
I think the issue here is that kbin simply doesn't have a lot of users yet.
One of the reasons I believe for that is also because the platform feels very stale or dead in plain sight.
This won't improve if you show people "0 people are viewing this thread" on every thread. Actually, it would worsen the impression that the site is dead.
Well, for the span tags, I haven't seen other tags being an issue. If you see a code block where the same issue occurs with other tags, tell me so I can update it.
If there is another Reddit exodus, for example, or if we get a surge due to the Threads thing, I feel like many will just turn back due to the UI alone.
I don't know if ernest's views changed since the last exodus, but iirc people joining the platform wasn't really his intention, it just happened. Kbin hasn't even had a proper full release yet, it's still beta software, so I don't think people bouncing off is that big an issue yet.
With the abandonment of Artemis (formerly kmoon), kbin is now only really usable by the mobile site.
That's the case for now, but app development is still happening with other projects:
ernest has mentioned intentions to revive his kbin app project