What are the different options in unused CSS?
FlyingPress can remove unused CSS from pages and extract only the required CSS. The generated used css is inlined (internal) in the HTML.
However, there are different options on what to do with the unused css.
Load Asynchronously: The rest of the CSS files are preloaded and load asynchronously. Safest option!
Load on User Interaction: Similar to 'load asynchronously', but instead of load CSS files instantly on page load, these files are loaded only after user interaction. User interaction can be mouse movement, scroll, touch, keyboard events etc.
Remove: Removes all unused CSS files, only required CSS files is left. We try to detect dynamically injected CSS classes but test it thoroughly. It might not be compatible with every theme/plugin.