Conditional Formatting change cell colour base on value

Hi,

I need help with the sheet attached, I want C1 cell change colour according to value in a1 and c1 itself.

If a1 =0 then c1 red
if a1 =1 then c1 no colour
if c1 = blank no colour
if c1 = text value light grey

Please help me if their is way to do this,
Thanks in advance for your time and help.
RRBook1.xls