What is the burden of proving all elements of an alleged sentence enhancement beyond a reasonable doubt?

"The People must prove all elements of an alleged sentence enhancement beyond a reasonable doubt." (People v. Miles (2008) 43 Cal.4th 1074, 1082.) "On review, we examine the record in the light most favorable to the judgment to ascertain whether it is supported by substantial evidence. In other words, we determine whether a rational trier of fact could have found that the prosecution sustained its burden of proving the elements of the sentence enhancement beyond a reasonable doubt." (Id. at p. 1083.)