Your template file may have a different name, so use the correct name in place of "template.css." Your HTML head section looks similar to this example: Save the HTML file.

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 ...

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.