Putting all 15kb CSS file inline on 100 pages of the site is not smart I think.
How do I pick which CSS classes and IDs from CSS file to put inline (and leave other ones on external CSS file) to a page so the Google Page Speed would give a better score?
I actually tried doing the following: I truncated the HTML code on a few of the main template pages of the site to leave only content that is visible on 1st screen without scrolling. Then I loaded these pages in browser and used CSS Usage FireBug addon to mark the unused CSS classes. To my wonder, only 9 classes were really unused. Maybe this method is not 100% right.
But seems that when I put all CSS into each page but not as an external CSS file, Google gives me 100/100 for mobile and desktop, but if I use that as an external file (that seems to be the right choice if not taking Google serious) I am only getting 84-90/100
Other question: Do I better get higher ranked by Google Page Speed and expect better SE traffic my way, or I don't mind that and make it the correct way by having external CSS file with all CSS content?