A graphic object can have default values for its properties,
which can be set at creation time.
In a style sheet, some property values may be inherited
at all levels and therefore come from the graphic object’s
default values. If you change such a property value in a style rule
to reflect a temporary state (such as selection), when the temporary
state no longer applies (the object is deselected), the property value
does not automatically revert to the default value. This situation
arises because there is no style rule to set the default value. You
therefore need to include this setting explicitly in the general rule
for the node or link. For an example, see
Resetting a default value after a state change.
If you do not change such a property value according
to a temporary state in a style rule, you can leave the implicit default
value and not worry about it.