This is what Google says for CSS:
This rule triggers when PageSpeed Insights detects that a page includes render blocking external stylesheets, which delay painting of content to the screen.
Fixing the issues using w3 Total Cache (we have written the settings for W3 Total Cache) 1.First run the Pagespeed and get all the URLs that are causing the issue and get the URLs it shows,we need them. 2.Now open Performance tab(i.e, W3 total cache settings) and navigate to Genereal Settings and Minify settings tab. 3.Now Enable the option minify and choose the option “Manual” in Minify Mode and other settings in the section should be like:
- Minify Cache Method – Disk
- HTML Minifier – Default
- JS Minifier – JSMin
- CSS Minifier – Default
Save the settings. 4.Now open the minify tab(in W3 Total cache from the sidebar) and move to the section “JS” and set the settings as given below:
- JS Minify settings: Enable
- Operations in Area for before Minify and Non-Blocking using “async” in embed type.