Code comments do not show up when the page is rendered, and can be a helpful way to communicate information to remixers, directly in the code, in context. This could include instructions for things to remix, coding tips, etc.
To add a comment to an HTML file, use this syntax
<!--your comment here-->
To add comments to a CSS file, use this syntax
/* your comment here */
// your comment here [be sure to include a line break at the end of your comment]