8 – Custom styles not taking effect

I’ve read and gone through several articles on sub-theming. Many are outdated! I cant find what i need.

I wish to base my Sub-Theme on the bootswatch Cyborg theme.
This is what i have done:

  1. Downloaded latest drupalBootstrap, extracted, enabled in drupal.
  2. Setup a sub-theme. As per Documentation instructions, by using the starterkits/THEMENAME project and Enabled in drupal.
  3. I wish to use bootswatch Cyborg theme so i downloaded its bootswatch.less and variables.less and put them inside My-Subtheme/css. I also copied over bootstrap.min.css.

Inside My-Subtheme.libraries.yml i have:

      css/style.css: {}
      css/bootswatch.less: {}
      css/bootstrap.min.css: {}
      css/variables.less: {}

Inside My-Subtheme/css/style.css:

@import 'bootstrap.min.css';
@import 'variables.less';
@import 'bootswatch.less';

.h1 {
    font-size: 200px;

In Appearance My-Subtheme Settings:
CDN Provider:jsDelivr, Theme:Cyborg

The styling is not taking effect.
What am i missing?