Replaced elements with an intrinsic aspect ratio use that aspect ratio, otherwise the box has no preferred aspect ratio. Size calculations involving intrinsic aspect ratio always work with the content box dimensions.

The box's preferred aspect ratio is the specified ratio of width / height. If height and the preceding slash character are omitted, height defaults to 1. Size calculations involving preferred aspect ratio work with the dimensions of the box specified by box-sizing.

Specifies that all the element's properties should be changed to their inherited values.

Specifies that all the element's properties should be changed to their initial values.

Specifies behavior that depends on the stylesheet origin to which the declaration belongs:

• If the rule belongs to the author origin, the revert value rolls back the cascade to the user level, so that the specified values are calculated as if no author-level rules were specified for the element. For purposes of revert, the author origin includes the Override and Animation origins.
• If the rule belongs to the user origin, the revert value rolls back the cascade to the user-agent level, so that the specified values are calculated as if no author-level or user-level rules were specified for the element.
• If the rule belongs to the user-agent origin, the revert value acts like unset.

Specifies that all the element's properties should roll back the cascade to a previous cascade layer, if one exists. If no other cascade layer exists, the element's properties will roll back to the matching rule, if one exists, in the current layer or to a previous style origin.

Specifies that all the element's properties should be changed to their inherited values if they inherit by default, or to their initial values if not.