Textpattern differs from many CMS solutions in that it stores the all template files (used to build the final page a browser sees) directly in the database as ‘styles’ (the CSS styling), ‘pages’ (the main page templates) and ‘forms’ snippets of code and logic that form building blocks within the ‘pages’.
However, many coders like to use their preferred IDE (integrated development environment) to write code and leverage all the tools within those applications provide to make code writing easier. That means you will have to copy/paste from your IDE into the corresponding parts of the Textpattern admin-side which adds a bit of time.
With CSS files you could simply use external stylesheet and link in the traditional way (see below). However there is another solution in the form of the ‘rah_flat’ Textpattern plugin, which effectively moves the ‘styles’, ‘pages’ and ‘forms’ back out of the database and into external directories for easier editing – a good solution when used in combination with an IDE. If you do use that plugin then dropping the files from this project into your correspondingly named directories will suffice. Detailed information on how to use rah_flat is available at the GitHub project.