Window border preferences

Hi.

I have a monitor with a slight issue (though many have similar) where the first row of pixels on the right and the left become invisible when I'm right in the centre of my monitor while being pretty close to it (about 2 feet). This gets incredibly annoying when I am on a dark theme on youtube for example and my borders are white / grey.

This results in if I make a slight movement of my head, these boarders come and go and they make me dizzy. The only themes I seem to be able to customise in mate that prevent this issue is by choosing one of the black ones such as ambient mate-dark or one of the other dark ones. I however don't want these as they make my whole interface look dark.

I do admittedly chose to use dark themes on many applications which is what gives me this issue. The applications are dark, with the boarder being a irritating line between that and the black edge of my monitor that comes and goes depending on my position. A simple fix would be if that edge could be black.

It is true that going fullscreen also eliminates this, but i very often have two windows open splitting the screen in half, and those boarders can't be removed then.

Is there any option to change these without dramatically changing the theme?

Thanks.