right click your row, choose "use browser height for row height"
Screenshot 2024-12-20 at 15.04.54.png
for top frame and bottom frame use: 0
now select your video in your grid, make sure it is aligned
Screenshot 2024-12-20 at 15.05.30.png
to middle
and make sure to use a square video.
this way you dont need to use css.