If you want to use @andrecool-68’s suggestion of adding the lexers to the context menu: in case it wasn’t clear, the arrow wasn’t meant to indicate that opening the Languages menu will give the popup in the screenshot – rather, he modified his right-click ContextMenu to include a Syntax Language folder which allows changing to his favorite list of languges. See this discussion, where we delve more deeply into how @andrecool-68 made that folder in the context menu. To make the edits, you will use Settings > Edit Popup ContextMenu to change the settings in contextMenu.xml. See the contextMenu docs here for more on the syntax.

Alternately, you could set up a script similar to the ones described in this other thread. The post I linked contains a script which toggles between XML and HTML, which could be quickly adapted to work with CSS and PHP. Throughout the thread, there are also examples of using a macro to just set the language instead of toggling, and other similar concepts.

To my knowledge, there is no lexer that contains PHP and CSS.
What you can try is something I have posted here.
But I don’t know if this is sufficient in your case.