Mai Theme comes with 9 built-in page layouts.
Layouts can be configured for archives, pages and posts - each post type can have a unique layout, and/or a default layout can be configured. Mai Lifestyle Theme is configured with the following settings - the page in this Live Preview is an Archive page.
You can see all the available layouts in action on the Mai Lifestyle Theme demo site..
Medium Content sets the base width of content to 800px, Small Content set the base width of content to 650px, and Extra Small Content sets the base width of content to 400px.