New theme seems nice, i'll probably swap to default and enjoy some of the new UI additions. The only thing standing out to me at the moment is the dynamic scaling of elements in the details bar, I like a large game video preview but the title and play button get huge, personally i'd like to clamp the max size of those elements.
Poked around and made some edits, it does feel like the those elements were a bit disproportionate compared to the rest of the UI in this arrangement, a before and after.