A small bit of UX feedback - when I type a search query that has no results, nothing happens. At first it made me think that the search form was broken. It would be better to show some kind of "no results" result to make it clear that the search has actually been performed.

I'm not in the market for a new pair of running shoes, but the site looks great - and I'm always happy to see more things being built in Elixir and Phoenix. Keep spreading the word!