To eliminate the white bars at the top and bottom of yad --html

[ecolinux74]

Hello,
For example, I launch 'yad --html --fullscreen --undecorated --borders=0 --escape-ok --no-buttons --uri="http://localhost:8080/blank.html"', but there are still white bars at the top and bottom. Is it possible to modify the code to make them disappear and have the viewport of the displayed HTML take up the entire screen?