The Center layout is available in the full version of Every Layout, which is still in production. All of the currently available layouts are marked "read now" in the index page.
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A full set of composable CSS layouts, documented with interactive examples and code generators
A library of interoperable custom elements (“layout components”) to experiment with and use in your applications.
Every Layout as a book, in the EPUB format, for reading offline and on planes.
Every Layout is here to help you learn (or relearn) CSS layout, using simple components (primitives) and a compositional approach. Understand and harness the power of modern CSS and the algorithms that power it.