Shifting Portal

Whenever you cast a blue instant or sorcery spell, you may search your library for a sorcery spell with converted mana cost 3 or less, reveal it then shuffle your library and put it on top of it.
Whenever you cast a red instant or sorcery spell, you may search your library for an instant spell with converted mana cost 3 or less, reveal it then shuffle your library and put it on top of it.