bootstrap above fold load ciritical css

https://www.appneta.com/blog/bootstrap-pagespeed/

Enable mod_pagespeed
<IfModule pagespeed_module>
    ModPageSpeed on
    ModPagespeedRewriteLevel CoreFilters
    ModPagespeedEnableFilters prioritize_critical_css
    ModPagespeedEnableFilters defer_javascript
    ModPagespeedEnableFilters sprite_images
    ModPagespeedEnableFilters convert_png_to_jpeg,convert_jpeg_to_webp
    ModPagespeedEnableFilters collapse_whitespace,remove_comments
</IfModule>

Minify CSS

yum compress JS and load async
$ cat jquery.js bootstrap.js holder.js > all.js
$ yui-compressor all.js -o all.min.js

Optimize CSS Delivery

Run a Javascript bookmarklet to detect and list CSS that is “above the
fold”
Inline the “above the fold” CSS directly into the HTML
Defer loading the rest of the “below the fold” CSS using a simple, yet
not cross browser compatible solution by Paul Irish

arba: https://github.com/addyosmani/critical