I have a lengthy CSS file (over 1K lines prepared by 3rd party)
e.g.
p {font-family: Arial;}
I want to have a build process that change all "font-family" under the p tag to
p {font-family: "Helvetica Neue", Helvetica, Arial, sans-serif}
Definitely I can modify the existing CSS file, but as it is lengthly and prepared by others (might update by them in the future, maintenance nightmare..), I am looking for some external build process that allow me to rewrite the CSS and produce a final CSS.
Is it possible with Less or SASS or other tools?