Claro content editing area is wider

The content editing area is wider now, with 60rem (960px, up from 832px) as the default for now. The size is exposed as a CSS3 variable so it is easier to override. To take advantage of CSS3 new :has() feature the code now checks if vertical tabs are used inside the layout and extends it to 68rem (1088px).

Example:

--layout-region-edit-width // New default width of 60rem, for basic layouts
--layout-region-edit-extended-width //New width for layouts which require more space (e.g. vertical tabs)