```
WARNING: Sass's behavior for declarations that appear after nested
rules will be changing to match the behavior specified by CSS in an upcoming
version. To keep the existing behavior, move the declaration above the nested
rule. To opt into the new behavior, wrap the declaration in `& {}`.
More info: https://sass-lang.com/d/mixed-decls
```
This is the first in a series of PRs to introduce a
ProseMirror-based
WYSIWYM editor experience
alongside our current textarea Markdown editor.
Behind a hidden site setting, this PR adds a toggle to the composer
toolbar, allowing users to switch between the two options.
Our implementation builds upon the excellent ProseMirror and its
non-core Markdown
module, using the
module's schema, parsing, and serialization definitions as the base for
further Discourse-specific features.
An extension API is included to enable further customizations.
The necessary extensions to support all Discourse's core and core
plugins features **will be implemented in subsequent PRs**.
---------
Co-authored-by: David Taylor <david@taylorhq.com>
