Body Box, Create a Default Color for Bold, for Posts and Pages

in Atahualpa/Style POSTS & Pages/Body Box I currently have the default font style for pages-posts set like this

font-style: normal;
font-weight: normal;
line-height: 1.5em;
color: #333333;
font-size: 1.1em;
font-family: Verdana, Helvetica, Arial, sans-serif;

I want to set it so when I make something bold, it automatically changes the color for that bold section to #666666, but only for a change to bold, not the rest of the text.
How do I do that?