Dear @Alastair .... thanks God I am a total nerd and I take this as a challenge LOL ....
There is no way to achieve that problem using the CSS technology used to template the dark theme due to the limitation of the actual language. In CSS lang, you need an object definition in order to access any property of any given object and in this case, that comes from the original HTML code itself. As there is no different definitions for every title in the table, there is no way to achieve that problem using CSS only.
HOWEVER ... I coded a small script in other scripting language for you that will solve your needs using other technology. You will need 2 steps :
a ) Install in your browers a new add-on called Custom JavaScript (I tested all this using chrome)
LINK : https://chrome.google.com/webstore/detail/custom-javascript-for-web/poakhlngfciodnhlhhgnaaelnpjljija
b) You need to copy the following script into the add-on for it to use it on any given Finviz URL:
highlights = ["Inst Own", "Shs Float", "Short Float", "Rel Volume",
"Avg Volume", "Volume", "ATR", "Price"];
hl_color = "Yellow";
highlights.forEach(function(hl) {
$("td:contains('"+hl+"')").css('color', hl_color).css('font-weight','800');
});
See screenshot attached too ! ... you will get a nice Yellow and Bold highlight on the strings you asked.
Hope this helps you .... if you need to pop up any other string, just modify the script to include it in the first variable between quotes and comma separated. Easy peasy !
Bests regards,
Paul.