Introduction
When to Use
Rails display optional accompanying content outside of the main viewport of your website. Sites often use rails with sticky content to fix additional—often optional—content to your viewport as you scroll through the page.
Fomantic's default rail is 300px
wide, just large enough to fit many common ad unit sizes, and just wide enough for a sub-navigation menu or a prominent call-to-action.
Adjusting Sizes
Railed content will most likely require arbitrary breakpoints that are specific to your site's content, to ensure they do not exceed the horizontal width of a user's browser.
Rails are generally used beside long, single-column containers with long-form content like blog posts, articles, or user profiles. Generally your main text container width should be set between around 600-800px
depending on your font size to optimize line length for readability.
This set-up means most tablet browsers can only accommodate a single rail. Ultrabooks and lower resolution computers two small rails, and larger monitors, usually two full-sized rails. The specifics of this implementation is left up to you in your project.
Types
Rail
A rail can be presented on the left or right side of a container
Internal
A rail can attach itself to the inside of a container
Dividing
A rail can create a division between itself and a container
Variations
Attached
A rail can appear attached to the main viewport
Close
A rail can appear closer to the main viewport
Size
A rail can have different sizes