word document scroll issue when viewing in IFrame

I am trying to view a word document inside an iframe, it is working but there is a div with id AppHeaderPanel and class .AppHeaderPanel.RaisedZIndexIncrease haveing z-index as 999 causing the issue with document scroll, because this header is hiding some scroll on top, so to scroll we first need to click bottom of header to click the scroll, please let me know how I can fix it, css is loading from https://res-1.cdn.office.net/officeonline/hashed/cd883d5a50cb022e/wordviewer.css