In Portfolio layout it would be great to add new 'special state' with a new style.
I read this: https://www.joomlart.com/documentation/purity-iii/override-joomla-com-content#extra-fields
I modified the portfolio.xml as described and it works, I have the new item in the combo.
It is not clear how to modify the style: in portfolio.less or portfolio.css I don't understand what should be modified. I checked the image portfolio-item-states.png, it includes 3 squared images for each of the existing status. Shall I add a four square?