Text colour buttons

Please post the url to a relevant page.

Try this in your custom css:

.variations_form tr td {background-color:#fafafa}
.variations_form label {padding-top:9px; color:#5a5a5a}

If your theme does not have a setting where you can enter custom css, you can use a plugin like this one:
https://ww.wp.xz.cn/plugins/simple-custom-css/

That is the actual paste content. The essential . (dot/full-stop) before both instances of variations_form is missing from your copy.