This is really great, it will soon make its way to HTG as well (with a few modifications)
I was just thinking that I like the mobile topic list a lot better than the desktop one, went looking and found this topic. Thanks!
What would be really nice would be to use this in about 2/3 the current width of the desktop topic list, and then add a navigation sidebar to the right with all the categories. Navigation to sections would be a lot more intuitive, I think.