Separation of content and presentation

Under this principle, visual and design aspects (presentation and style) are separated from the core material and structure (content) of a document.

This principle is not a rigid guideline, but serves more as best practice for keeping appearance and structure separate.

In many cases, the design and development aspects of a project are performed by different people, so keeping both aspects separated ensures both initial production accountability and later maintenance simplification, as in the don't repeat yourself (DRY) principle.

Under this methodology, academic writings and publications can be structured, styled and typeset with minimal effort by its creators.

In fact, it also prevents the end-users — who are usually not trained as designers themselves — from alternating between tweaking the formatting and working on the document itself.