The Subrion CMS Announcements plugin allows administrators to leave their messages or announcements to the Front End Block of their web site.
There are several styles, available for Announcements block:
To change style, go to Admin Dashboard -> Content -> Blocks. Click on Edit Announcements block. In the 'CSS class name' config field, enter your desired class name like this: "an an--success" (without the quotes).
Installation is a very simple process. Just click Install and the plugin installation will be performed.