I don't think. (EDIT: so. lol) ;-( There might be a method outside of character sheet code, ie Stylish or similar. You can define a width for the sheet's outermost element, but if it's wider than the character journal you'll have to use horizontal scrolling and/or resize to see everything. If it's smaller, you end up with extra white space. If you make your sheet responsive, it can conform to the width of the journal regardless. CSS grid and flexbox have seemingly become the preferred method for character sheets and adapt well to re-sizing.