2 A progress element should have a nested shadow box with a width specified:
5 | style="-webkit-appearance: none;"
9 | pseudo="-webkit-progress-inner-element"
10 | shadow:pseudoId="-webkit-progress-inner-element"
12 | pseudo="-webkit-progress-bar"
13 | shadow:pseudoId="-webkit-progress-bar"
15 | pseudo="-webkit-progress-value"
17 | shadow:pseudoId="-webkit-progress-value"