Hi Lauren,
The best way to change the content width would be to first create a child theme for Coraline (that way, your changes won’t affect the Coraline theme itself). Then, in the child theme’s “style.css” file, you can adjust the content width with CSS.
You’ll also want to create a “functions.php” for your child theme and adjust the $content_width variable to reflect the new width, so that any new attachments you upload in the future will be sized properly.
For example, the default content width is 500px (as you can see at the top of Coraline’s functions.php).
There’s technically no maximum width, it depends on your preferences. For best readability, however, you may not want to make your content too wide.
I hope this helps, let us know if you have further questions.
