How do we review questions of law and law in a personal injury case?

We apply the substantial evidence standard to the trial court's factual findings, and we review questions of law de novo. We also review "mixed questions of fact and law [that] require 'a critical consideration, in a factual context, of legal principles and their underlying values' " independently. (Bono v. Clark (2002) 103 Cal.App.4th 1409, 1421.) Our review in this case is de novo because the questions whether the clerk could properly reject the second application when it was submitted for filing and whether the trial court had authority to order the second application deemed filed as of the date it was submitted are primarily legal.