Hello,
1) The Template Manager supports all the way up to a 2em default which is twice the size of the standard font size. You can also enable the "Font Resizer" javascript under the Javascripts Tab to allow users with vision disabilities to increase the font size further.
2) To change the color of all the text within the articles you can add this to the custom.css and adjust as needed.
#s5_component_wrap {
color: #ff0000 !important;}