Ecwid allows you to change CSS styles of customer storefront, including colors, fonts, margins, and images. This helps your integrated Ecwid store match the design of your site completely.
HTML is not available for editing, that is you can’t change the interface logic (how Ecwid behaves). We believe that most HTML changes people do are outside of Ecwid boundaries.
Ecwid does not need those "change header HTML / change footer HTML" functionality. The site owner can change the layout of the whole site. And CSS capabilities within Ecwid are more than enough for you to make Ecwid look as an integral part of your site.
In most cases, you won't have to edit anything, not even the CSS. Just pick one of the pre-defined themes. Ecwid is designed to fit well in most sites.
If you’d like to change some elements in your store, our article about changing design will guide you through this process and give you many ready-to-use solutions.