"Eliminate render-blocking CSS in above-the-fold content"

I've been using Google PageSpeed insights to try and improve my site's performance, and so far it's proven extremely successful. Things like deferring scripts worked beautifully, since I already had an in-house version of jQuery's .ready() to defer scripts until the page had loaded fully, all I had to do was inline that particular function and move the full scripts to the end of the page. That worked great.

But now I find myself glaring at the one remaining yellow dot on the checklist: "Eliminate render-blocking CSS in above-the-fold content".

The way my CSS is set up is to have one global _.css file containing styles that apply to the page structure in general, or are used in more than one or two places across the site. Most pages then have an associated CSS file (for instance, party.php has party.css) containing styles specific to that particular page. All CSS files are cached indefinitely, as I append /t=FILEMTIME to filenames (and later remove them with .htaccess) in order to guarantee that files are updated when they are changed.

So anyway, Google recommends inlining critical styles needed for above-the-fold content. Trouble is... well, take a look at this screenshot: http://prntscr.com/1qt49e

As you can see... ALL of the content is above-the-fold! People hate scrolling, especially on a game that involves loading many pages. So I designed the site to fit on one screen (assuming a good enough resolution). So that means... ALL of the styles apply to above-the-fold content! So... is there any solution? Or am I stuck with that yellow mark on an otherwise near-perfect score?

A related question has been asked before: What is “above-the-fold content” in Google Pagespeed?

Firstly you have to notice that this is all about 'mobile pages'.
So when I interpreted your question and screenshot correctly, then this is not for your site!

On the contrary - doing some of the things advised by Google in their guidelines will things make worse than better for 'normal' websites.
And not everything that comes from Google is the "holy grail" just because it comes from Google. And they themselves are not a good role model if you have a look at their HTML markup.

The best advice I could give you is:

• Set width and height on replaced elements in your CSS, so that the browser can layout the elements and doesn't have to wait for the replaced content!

Additionally why do you use different CSS files, rather than just one?
The additional request is worse than the small amount of data volume. And after the first request the CSS file is cached anyway.

The things one should always take care of are:

• reduce the number of requests as much as possible
• keep your overall page weight as low as possible

And don't puzzle your brain about how to get 100% of Google's PageSpeed Insights tool ...! ;-)

Addition 1: Here is the page on which Google shows us, what they recommend for Optimize CSS Delivery.

As said before, I don't think that this is neither realistic nor that it makes sense for a "normal" website! Because mainly when you have a responsive web design it is most certain that you use media queries and other layout styles. So if you are not gonna load your CSS first and in a blocking manner you'll get a FOUT (Flash Of Unstyled Text). I really do not believe that this is "better" than at least some more milliseconds to render the page!

Imho Google is starting a new "hype" (when I have a look at all the question about it here on Stackoverflow) ...!

How I got a 99/100 on Google Page Speed (for mobile)

TLDR: Compress and embed your entire css script between your <style></style> tags.

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I've been chasing down that elusive 100/100 score for about a week now. Like you, the last remaining item was was eliminating "render-blocking css for above the fold content."

Surely there is an easy solve?? Nope. I tried out Filament group's loadCSS solution. Too much .js for my liking.

What about async attributes for css (like js)? They don't exist.

I was ready to give up. Then it dawned on me. If linking the script was blocking the render, what if I instead embedded my entire css in the head instead. That way there was nothing to block.

It seemed absolutely WRONG to embed 1263 lines of CSS in my style tag. But I gave it a whirl. I compressed it (and prefixed it) first using:

postcss -u autoprefixer --autoprefixer.browsers 'last 2 versions' -u cssnano --cssnano.autoprefixer false *.css -d min/ See the NPM postcss package.

Now it was just one LONG line of space-less css. I plopped the css in <style>your;great-wall-of-china-long;css;here</style> tags on my home page. Then I re-analyzed with page speed insights.

I went from 90/100 to 99/100 on mobile!!!

This goes against everything in me (and probably you). But it SOLVED the problem. I'm just using it on my home page for now and including the compressed css programmatically via a PHP include.

YMMV (your mileage may vary) pending on the length of your css. Google may ding you for too much above the fold content. But don't assume; test!

Notes

1. I'm only doing this on my home page for now so people get a FAST render on my most important page.

2. Your css won't get cached. I'm not too worried though. The second they hit another page on my site, the .css will get cached (see Note 1).

Few tips that may help:

• I came across this article in CSS optimization yesterday: CSS profiling for ... optimization
  A lot of useful info on CSS and what CSS causes the most performance drains.

• I saw the following presentation on jQueryUK on "hidden secrets" in Googe Chrome (Canary) Dev Tools: DevTools Can do that. Check out the sections on Time to First Paint, repaints and costly CSS.

• Also, if you are using a loader like requireJS you could have a look at one of the CSS loader plugins, called require-CSS, which uses CSSO - a optimzer that also does structural optimization, eg. merging blocks with identical properties. I used it a few times and it can save quite a lot of CSS from case to case.

Off the question: I second @Enzino in creating a sprite for all the small icons you are loading. The file sizes are so small it does not really warrant a server roundtrip for each icon. Also keep in mind the total number of concurrent http requests are browser can do. So requests for a larger number of small icons are "render-blocking" as well. Although an empty page compare to yours, I like how duckduckgo loads for example.

Please have a look on the following page https://varvy.com/pagespeed/render-blocking-css.html . This helped me to get rid of "Render Blocking CSS". I used the following code in order to remove "Render Blocking CSS". Now in google page speed insight I am not getting issue related with render blocking css.

<!-- loadCSS -->
<script src="https://cdn.rawgit.com/filamentgroup/loadCSS/6b637fe0/src/cssrelpreload.js"></script>
<script src="https://cdn.rawgit.com/filamentgroup/loadCSS/6b637fe0/src/loadCSS.js"></script>
<script src="https://cdn.rawgit.com/filamentgroup/loadCSS/6b637fe0/src/onloadCSS.js"></script>
<script>
      /*!
      loadCSS: load a CSS file asynchronously.
      */
      function loadCSS(href){
        var ss = window.document.createElement('link'),
            ref = window.document.getElementsByTagName('head')[0];

        ss.rel = 'stylesheet';
        ss.href = href;

        // temporarily, set media to something non-matching to ensure it'll
        // fetch without blocking render
        ss.media = 'only x';

        ref.parentNode.insertBefore(ss, ref);

        setTimeout( function(){
          // set media back to `all` so that the stylesheet applies once it loads
          ss.media = 'all';
        },0);
      }
      loadCSS('styles.css');
    </script>
    <noscript>
      <!-- Let's not assume anything -->
      <link rel="stylesheet" href="styles.css">
    </noscript>

I too have struggled with this new pagespeed metric.

Although I have found no practical way to get my score back up to %100 there are a few things I have found helpful.

Combining all css into one file helped a lot. All my sites are back up to %95 - %98.

The only other thing I could think of was to inline all the necessary css (which appears to be most of it - at least for my pages) on the first page to get the sweet high score. Although it may help your speed score this will probably make your page load slower though.

The 2019 optimal solution for this is HTTP/2 Server Push.

You do not need any hacky javascript solutions or inline styles. However, you do need a server that supports HTTP 2.0 (any modern server version will), which itself requires your server to run SSL. However, with Let's Encrypt there's no reason not to be using SSL anyway.

My site https://r.je/ has a 100/100 score for both mobile and desktop.

The reason for these errors is that the browser gets the HTML, then has to wait for the CSS to be downloaded before the page can be rendered. Using HTTP2 you can send both the HTML and the CSS at the same time.

You can use HTTP/2 push by setting the Link header.

Apache example (.htaccess):

Header add Link "</style.css>; as=style; rel=preload, </font.css>; as=style; rel=preload"

For NGINX you can add the header to your location tag in the server configuration:

location = / {
    add_header Link "</style.css>; as=style; rel=preload, </font.css>; as=style; rel=preload";
}

With this header set, the browser receives the HTML and CSS at the same time which stops the CSS from blocking rendering.

You will want to tweak it so that the CSS is only sent on the first request, but the Link header is the most complete and least hacky solution to "Eliminate Render Blocking Javascript and CSS"

For a detailed discussion, take a look at my post here: Eliminate Render Blocking CSS using HTTP/2 Push

Consider using a package to automatically generate inline styles from your css files. A good one is Grunt Critical or Critical css for Laravel.