Feature: #79622 - SpaceBefore- and SpaceAfterClass for Fluid Styled Content

See Issue #79622

Description

CSS Styled Content provided the possibility to the editor to fine-tune distances between content elements. The concept of CSC relied on the editor understanding what margins are, how they are calculated and had to maintain an overview of pixels that were used on the site he/she is maintaining.

This led to different problems not only for the editor but also for the integrator because he had no control about what the editor fills into these fields. Also it was hardly controllable when these distances should be variable and change on certain viewports for mobile usage.

To regain control over this behaviour we are now introducing a new concept that purely relies on CSS classes, that can be defined by the integrator.

All CSS classes are prefixed with frame-space-before- or frame-spacer-after- by default and added to the surrounding frame when available. If the frame of the content element is set to none, placeholder elements are placed before and after to generate that distance.

The default CSS definitions are placed in the optional static template Fluid Content Elements CSS (optional). If this is not included only the CSS classes will be added but without having CSS rules matching these classes.

Example for before classes

SpaceBefore and SpaceAfter is now available to all Fluid Styled Content elements.