removing stylesheet from base theme In our Drupal 8 theme we are using the classy base theme. themes/mytheme/mytheme.info.yml:

base theme: classy


Using the information from drupal.org/docs/8/theming-drupal-8/adding-stylesheets-css-and-javascript-js-to-a-drupal-8-theme I am trying to remove some stylesheets from the base theme - but I cannot figure out the right way to do so. For instance, I want to remove the css/components/form.css stylesheet from the base theme. So far I tried:

libraries-override:
  base:
    css:
      component:
        css/components/form.css: false




libraries-override:
  core/base:
    css:
      component:
        css/components/form.css: false




libraries-override:
  core/classy:
    css:
      component:
        css/components/form.css: false


None of which is working. Removing the stylesheet with stylesheets-remove would work fine - but this is deprecated and I would rather use the new intended way for Drupal 8+.

What is the correct way of removing/addressing/extending a library from the base theme?
It's classy/base:

libraries-override:
  classy/base:
    css:
      component:
        css/components/form.css: false


Which is defined in the classy.info.yml.