{all} Property | CSS: Presentation Layer
Standards Based Development
all property is a shorthand that resets all properties; all only accepts css-wide keywords.
Specifing all:default on an element will block all inheritance and reset all of its properties, as if no rules appeared in the author level of the cascade. One possible use is the root element of a widget included in a document, which does not wish to inherit styles of the outer page.
Specifying all:initial on an element blocks inheritance and resets all properties, as if no rules appeared in the author, user, or user-agent levels of the cascade.