The 'outline' property is a shorthand method for specifying the
'outline-color', 'outline-style', and 'outline-width' properties
using a single property notation.
The outline properties create a uniform line around an object in
order to draw visual attention. An outline is slightly different
than a border in several ways: An outline is drawn starting "just
outside the border edge" and is allowed to be non-rectangular.
Outlines are always rendered on TOP of an element's rendering box
and do not influence the box's position or size calculation; the
document does not need to be re-flowed when a border is rendered or
hidden, but the outline may overlap other nearby elements.
Explicitly sets the value of this property to that of the parent.