How do I learn to code in HTML and CSS on my Mac? Web design is one of the most useful skills you can learn, and it’s easy to learn HTML and CSS (the two main pillars of web pages) in Mac OS X ...

Traditionally, graphic designers create a website’s template, and programmers build coding (HTML, CSS) to add pages, sub-pages, and features to it.

Get a feel for it; on the sidebar you'll see "main-style.css" as well as an HTML page for every page on your website. Select "main-style.css" to view the stylesheet in Weebly's editor.