Should be nothing harder than a simple css change in the theme. Unfortunately I don't know what features CAF provide in that regard (whether it's a fixed theme you cannot change, or whether you can customise it).
Edit: For the admins, there is a "Style Manager" in the Administration Centre. If you go in there, you can't edit the default style directly but you can create a new one.
For the quotes, if you do that, then find this section:
blockquote.bbc_alternate_quote,
blockquote.bbc_standard_quote {
padding: 15px 10px;
border-style: solid;
border-width: 0 0 3px;
border-color: #b5c4cc;
background-color: #e0eef6;
color: #768094;
}
The "color" value is the text colour, in hex, but you can also use css colour names too,
https://www.quackit.com/css/css_color_codes.cfmIf you add a "font-size" item, you can also change the font size.
color: black;
font-size: small;
Then just need to "Pick" the style back on the style manager page. If you make a mistake just delete the new style and it should revert to the default.