White lines between block

Hi,

I'm experiencing an issue similar to the issue that was reported here: White lines between blocks in Edge | E-Learning Heroes

Apparently, a solution was found, but it does not say what. I'm experiencing the same problem, a faint white line, even though the padding is set to zero. Although for me, it's also happening in Google Chrome and Edge. The line disappears when the browser window is resized to its maximum size, but reappears when it's shrunk, and ruins the continuity of the design, If the solution could be shared that would be most helpful!

Many thanks