I followed the Drupal Bootstrap sub-theming documentation: basically copied the CDN starterkit and renamed all the files and it seems to work. I then added a line to the empty css/style.css.

At first it didn't work except when I went to /admin/appearance/settings/ and clicked the advanced tab and set the theme to 'Bootstrap (Default)'.

I then made more modifications to the style.css, this time it didn't refresh on the pages. Checking the rendered pages I found the css file is coming as a mangled named css file.

What is involved in generated this mangled file and how to refresh after modifying css/style.css?

Can I choose a different theme from the Bootstrap settings page and still use my css modified styles?

1 Answer 1


The mangled file comes from aggregating CSS files. You will need to clear/flush the cache in order to see changes.

You can turn CSS caching off by going to /admin/config/development/performance and unchecking aggregate CSS files. Now you don't need to clear the cache to see CSS changes.

enter image description here

PS: Remember to turn this back on when your website is ready for production/going live.

  • Now when I change libraries.yml it doesn't refresh, what is the correct way to make it refresh instantly or otherwise what is the manual way?
    – Bishoy
    Jul 18, 2016 at 15:38
  • 1
    @Bishoy, for changes on other non .css or .js files, you will have to disable caching all together. You can by following this tutorial
    – No Sssweat
    Jul 18, 2016 at 23:40
  • 1
    @Bishoy The manual way is to clear/flush the cache, but that can get annoying during development. If you want to see changes after page refresh without needing to clear the cache on non .css or .js files, follow this tutorial. Remember that this is just for developing, you will want to revert this once your site is ready for show time.
    – No Sssweat
    Jul 19, 2016 at 0:09

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