So although I am taking things rather slowly, I am in fact still working on Power-Ups for Autoptimize, focusing on the one most people were asking for; critical CSS. The Critical CSS Power-Up will allow one to add “above the fold”-CSS for specific pages or types of pages.
The first screenshot shows the main screen (as a tab in Autoptimize), listing the pages for which Critical CSS is to be applied:
The second screenshot shows the “edit”-modal (which is almost the same when adding new rules) where you can choose what rule to create (based on URL or on WordPress Conditional Tag), the actual string from the URL or Conditional Tag and a textarea to copy/ paste the critical CSS:
The next step will be to contact people who already expressed interest in beta-testing Power-Ups, getting feedback from them to improve and hopefully make “Autoptimize Critical Css” available somewhere in Q3 2016 (but no promises, off course).