BrandNav

You want to change the text size and color of what part of the website? The navigation? The copytext?

This bit of CSS defines your header colors:

h1, h2, h3, h4, h5, h6, a.site-title, .entry-title a {
    color: #F68D04;
}

and this bit of css defines the color the text inside your <p> and </p> tags:

#page {
    color: #FFFFFF;
}