Data tables

Hello,
Small problem with css.
I create tables one below the other on a page. And happy Addons is the only one that works very well. The others generate too many requests and it takes too long to open and sometimes it bugs. I just have a css problem. On a desktop computer, everything works perfectly when certain “boxes” have a black background and white writing but on a laptop from the second table onwards the box with the black background is white with a black frame and of course the writing no longer appears. This “means” that it’s the “general” css that “wins”. A clue, perhaps!
Thanks in advance for your help