Can you share a link please? I would look at the grid heights. If the two elements are in separate grids and heights are vh-base, it might be doing this.
Consider stacking those two elements?
Try this link, https://berzas7.editorx.io/mysite Thanks
I want to align text box below video and the page to be in fullscreen
Great. Is that video and text block residing in a shared grid or do they each have their own row?
It looks like the video is in its own section, grid or grid row and that is set to be the same height between ALL break points. You can either set it the height to auto or match the video fundamental height until you hit other breakpoints, which at that time, I would have it go bigger than keeping it at the same percentage with all the way through the screen sizes and device.
Utilize Min Heights and Min Widths from the get go and you will find it easier to manage.
Now they are in shared grid, but i tried to put them in separate rows as well as in separate containers