mixin to calcul columns

assets/sass/_theme/_configuration.sass

assets/sass/_theme/_utils.sass

assets/sass/_theme/blocks/base.sass

assets/sass/_theme/blocks/call_to_action.sass

assets/sass/_theme/blocks/chapter.sass

assets/sass/_theme/blocks/contact.sass

assets/sass/_theme/blocks/datatable.sass

assets/sass/_theme/blocks/definitions.sass

assets/sass/_theme/blocks/features.sass

assets/sass/_theme/blocks/image.sass

assets/sass/_theme/blocks/organizations.sass

assets/sass/_theme/blocks/pages.sass

assets/sass/_theme/blocks/persons.sass

assets/sass/_theme/blocks/posts.sass

assets/sass/_theme/blocks/testimonials.sass

assets/sass/_theme/blocks/timeline.sass

assets/sass/_theme/design-system/button.sass

assets/sass/_theme/design-system/hero.sass

assets/sass/_theme/design-system/layout.sass

assets/sass/_theme/design-system/nav.sass