I’m wondering if you may have a syntax error, which is preventing it from minifying?
On line 1509 of your CSS file, you have formatting that I have not seen before, or can find answers to. Try fixing the syntax to see if that works.
.link-badge ? span:after,
.link-badge ! span:after {
display: none;
}
You also have an empty ruleset, which you might want to consider removing unless you plan to use it in the future.
.growfast-mega-menu .growfast-mega-menu__col {}