these show female/male school outfits from many animes
it might be a good spot to start, get an idea of what will fit into the LL anime
(a very brief look i didnt see male charaters)
once you can say or describe a design you believe fits into your cosplay
then others will be able to point out specific examples
also, im fairly sure that gender specific fashion design dosnt translate directly
so youll more likely be looking for a male outfit base design, then take some artistic liberty
adding in detailing from the female character choice, directly or editing it to be more "masculine"