CSS variables inside other functions are incorrectly minified

[PrathamSV]

CSS variables when placed inside other functions (like calc(...)) are incorrectly minified.

That is, calc(100% - var(--gradient-width)) becomes calc(100% - var( - - gradient - width))

In my case,

linear-gradient(
        to right, 
        #000 0%,
        rgba(0,0,0,0.15) var(--gradient-width) calc(100% - var(--gradient-width)),
        #000 100%
    );

gets minified into:

linear-gradient(to right,#000 0%,rgba(0,0,0,0.15) var(--gradient-width) calc(100% - var( - - gradient - width)),#000 100%)

My styles are written in SCSS
And jekyll-minifier version is 0.2.2

For now,

sass:
  style: compressed

jekyll-minifier:
  exclude: "*.css"

provides some compression without the bug.