"the unique roman temple that was dedicated to "all of the gods" and combined a cylindrical domed cella with a standard temple porch is the: "

Pantheon is a roman temple that was dedicated to all gods. The old roman temple was now formed into a church in Rome, Italy. The cylindrical domed cella and a standard porch was unusual in the architectural forms. Cella is a latin term for a chamber. In the roman temples, the cella contains sculpture representing the gods.  

a dark purple with a little bright violet red