Da Vinci was a perpetual experimenter and tinker. Like many others, he made (presumably all of) his own paints and inks from raw materials. He tried all sorts of new media and formulae, sometimes with utter failure as a result (e.g., The Battle of Anghiari fresco in the Palazzo Vecchio). Many of the materials he used, such as linseed oil (for paint) and other oils, charcoal, chalks, etc. were quite common. Some pigments he used were rare, but remember he operated in Florence, Milan, and Venice, which were hubs of trade in his day, so while he may have relied mainly on what was obtainable in his immediate area, he had access to foreign goods.

His work incorporates so many media and subjects I think its fair to say that there were no limitations on his choice of subject. I'm not sure what exactly you intend by "style", though. He had incredible attention to detail and much of his work shows that extreme care was taken to reproduce the finest details of fabric or hair; this seems to be fairly irrespective of the media.

He would use the media to their full effect; for example, he would blend chalk, charcoal, and even paint with his hand, but in ink I have never seen work where he deliberately smeared it, so I suppose in that sense there were some practical limitations. An art history scholar can hopefully shed some more light here.