the “editor” is a special block class. it's css is used in the backend and the frontend. In the backend, the class name like “.editor-content” is attached to the body of the editor, not to a div. Use “div.editor-content” (with the elements name) only if you need to style the container in the frontend. For all other stylings, like paragraphs, lists, etc., use “.editor-content p”, “.editor-content ul”, etc. The .editor-class is attached to the <body>-element when in the backend, thus div.editor-content only works in the frontend. This is okay and needed if you have to position only the block's container div.editor-content in the frontend, but for all elements within div.editor-content, don't use the elements name 'div.' in the css, otherwise we have to rewrite it to make it work in the backend editor.
.editor‐blocks may contain only <h1>‐<h6>, <p>, <strong>, <em>, <hr />, <br />, <img>, <ul>, <ol>, <li>, <table>, <caption>, <thead>, <tbody>, <tfoot>, <tr>, <td>, <blockquote>, <span> (only in rare cases, use <em> or <strong> instead of <span> wherever possible, <span> is not editable well with the editor-component we use in our cms (TinyMCE))
You can use forms in blocks to wrap form elements, just not within the “editor” block.
inside the editor-styles, for right floating img, use “img.align-right”, for left floating img, “img.align-left”. These are standard for .editor-blocks and the only classes which contain a reference to their layout. In other blocks, refer directly the element <img> for styling or use your own class.
Do not use tables for layouting. Tables are allowed within .editor-blocks, e.g. for price lists. If there are such, don't style tables globally, only within the css for the .editor, like .editor-content table { … }
for .editor-blocks, style at least all headings, from <h1>-<h6>, <p>, <ul> and <ol>, <img> (floating and inline) and <a> (hover and normal state).