Headings: H3 Color Change

Re: smithmedicalwriting.com

I would like to change my H3 (heading) colour to HEXA #00A19A. On this page (http://www.smithmedicalwriting.com/services-3/) I want the headings, located next to the icons changed to my HEXA colour.

When I open my CSS Style Sheet, however, this is all I see:

/*
Theme Name: Aqua
Description: A business, portfolio and blog theme.
Author: BlueOwlCreative
Theme URI: http://blueowlcreative.com/wp/aqua
Author URI: http://blueowlcreative.com
Version: 1.5
License: GNU General Public License
License URI: license.txt
*/

@import url(“stylesheets/skeleton.css”);
@import url(“stylesheets/stylesheet.css”);
@import url(“stylesheets/flexslider.css”);
@import url(“stylesheets/prettyPhoto.css”);
@import url(“stylesheets/carousel.css”);

---

Could you let me know where I should change the CSS? There is also nothing found in the ‘Edit CSS’ or ‘Customize’ sections in the WP dashboard.

Thanks so much!