Similar to components themes are designed to store the reusable files. But unlike components themes are used to pre-configure site layouts and branding, e.g. blog, technical documentation, user guides, API reference etc.
Theme files are copied to the root directory of the site.
For example the following theme
_themes theme1 _assets images logo.png scripts main.js styles main.css _layouts default.html article.html _config.yml
Applied to the site below
_assets images logo.png site.png _layouts default.html index.md _config.yml
Would result into the following structure
_assets images logo.png site.png scripts main.js styles main.css _layouts default.html article.html index.md _config.yml
Unlike components, different themes will not generate a conflict error in case the same file names are used. Instead, Docify engine will follow the merging rule to merge and override files.
In the example above _assets\images\logo.png and _layouts\default.html files from the theme will be overriden with the corresponding files from the site, while _config.yml files will be merged.
Themes are encouraged to have overridable files so the consumer can tailor the theme to their needs.
The theme itself can have a parent theme. In this case, it should have a _config.yml file with the theme attribute. For example, if the _config.yml of the theme in the example above will have the following attribute, the files from the base theme will be also merged to a site following the same merging and overriding rules.
Refer the standard library themes section for an example of themes.