We have Design (parse) files which include the deprecated Linked CSS Design Area (since 5.4.4.0).
Using these Design parse files are a number of sub-sites which have their own customisation and within that customisation a reference to a CSS file to add specific styling to that sub-site. All sub-sites also reference a master CSS style sheet included in the Design file.
Question: what is the recommended method of adding custom CSS files to sub-sites with their own customisation without the availability of the now deprecated ‘Linked CSS Design Area’?
Best way is to use a Standard page asset, set the contents of it to Raw HTML, then manually code your CSS tag in there and point to the CSS file src using ./?a=, then nest that Standard Page in to the design using a nested design area.