Go for MR blues, flat MR for early sustain or scaling MR for late game.
Yellows i prefer to go flat armor but i chose scaling HP for this build, because this build in
general will give you alot of armor and not so much MR.
Reds pick armor runes.
Quints go either armor or magic resist, depending on enemy teamcomp.
Yes i know that you will get more CDR then the cap is set to, but you will be tanky AF.
Boots should not be an item needed to get as you will counter the enemies who are high mobile champions with this build.