How can I change font color for my blog posts in Manifest theme by using CSS?

http://wylersblog.com/ is using Twenty Eleven, not Manifest.

To change out the base font color in the Manifest theme, try this:

#core-content p, #core-content li, #core-content dd {
color: midnightblue;
}

Change the color name as necessary. Note that this only changes the base font color, if there are any other specific colors for text set in the theme, then you would also need to change those out as you go. If you need help finding them, please send a link to the blog you're working on and point out the specific text you'd like to change.

To change out the base font color in the Twenty Eleven theme, try this:

body {
color: wheat;
}

Again, this only changes the base font color and other colors may need to be adjusted separately.