From the Stalfos documentation site:
I built Stalfos as a boilerplate for building out front-end templates for web projects. It’s designed to also continue powering the front-end for the project’s lifespan, as a separate entity that lives alongside the main codebase.
Built around core CSS
The CSS is the main feature of Stalfos as it provides a solid starting point without encroaching on your design like Bootstrap and Foundation can do. By providing a grid system and core layout components, it prevents you from having to write the core foundations of layout over and over again.
By providing useful mixins and helpers, Stalfos tries to encourage a modular setup for your CSS whilst staying out of the way as much as possible.
Built to assist
Secondary to the CSS framework, Stalfos provides a gulp-based system for dealing with your core assets such as images, SVG and fonts.
It also provides a mechanism for building static templates with Nunjucks with a handy data system to help prevent repeated markup bloating your template files.
All-in-all, Stalfos is there to help and has been an absolute pleasure to work on over the last couple of years.