LRDOCS-298 states, that with a hook a css file can be overwritten.
It is true - technically - but we uses sass-cache and while the css file is overwritten when deploying a hook, the sass-parser will not run, so the sass-cache will not be modified.
So with default portal properties, the css modification will not reach the browser.
- in Eclipse with Liferay plugin, only the jsp/jspf files can be browsed for hooks, not css nor js
- there is no dtd element for css
- there is no info about it in the training guide