... 6.1 Specified, computed, and actual values . ... 6.2 Inheritance . ... Once a user agent has parsed a document and constructed a document tree , it must assign, for every element in the tree, a value to every property that applies to the target media type . ... User agents must first assign a specified value to a property based on the following mechanisms (in order of precedence): . ... By default, rules in an author's style sheet override those in a user's style sheet (see cascade rule 3). ...