Had another look and you may need to include a few more classes as follows

.x126, .x127, .x128, .x129, .x130, .x131{
color:#000000 !important;
Border 2px solid black !important;
}

The style  hierarchy is complex in this site. I would suggest that in your CSS
sheet you put

.x126, .x127{
color:#000000;
}

However the page  is so complex that I am not sure if that is overridden by a
later style somewhere.

The borders are more complex as they are overridden by inline styles.

You could try putting in the style declaration above:
"Border 2px solid black !important;" In fact you could also use the
!important declaration for the color as well (it overrides subsequent and
higher ranking styles) so the final style declaration would be

.x126, .x127{
color:#000000 !important;
Border 2px solid black !important;
}

Can you please tell me exactly where to place the coding that you
suggested.

I am not certain if the site has a global style  sheet. If it has you might
put the style information there. If not, there is probably a style section in
the header of the page  and it could go there, but that means that you have to
put the style directives in every sheet  affected. That is why we use global
style sheets  - you only do it once. You would insert my suggested code on the
line following any close brace }