GA-Z77x-UD5H, i3770, HD 4000 graphics--compatible with Sierra?

I have a fully functional Chimera/Mavericks system : GA-Z77X-UD5H, i3770, 8 gb ram, internal graphics HD 4000. I want to upgrade to Clover/Sierra. Is Sierra compatible with HD 4000 graphics or do I need to install a graphics card before I upgrade? Any issues with my motherboard/processor combination?

Thank you--Jim