Styel sheet Add / Remove / Override

Example :

# Add a new CSS file:

stylesheets:

  all:

    - layout.css

# Override an existing CSS file:

stylesheets-override:

  - system.theme.css

# Remove an existing CSS file: (Example : to remove barik colors.css file)

stylesheets-remove:

  - core/themes/bartik/css/colors.css