Hard-code screen widths in one file, but then define variables that can be used across all breakpoints?

gistfile1.txt

@media (min-width: 25em) { /* 400px @ 16px font size -- XS */
  :root {
    --screen: 25em;
    --max-area: 20em;
  }
}
@media (min-width: 34em) { /* 544px @ 16px font size -- SM */
  :root {
    --screen: 34em;
    --max-area: 30em;
  }
}
@media (min-width: 48em) { /* 768px @ 16px font size  -- MD */
  :root {
    --screen: 48em;
    --max-area: 42em;
  }
}
@media (min-width: 62em) { /* 992px @ 16px font size -- LG */
  :root {
    --screen: 62em;
    --max-area: 60em;
  }
}
@media (min-width: 75em) { /* 1200px @ 16px font size -- XL */
  :root {
    --screen: 75em;
    --max-area: 70em;
  }
}
@media (min-width: 90em) { /* 1440px @ 16px font size -- XXL  */
  :root {
    --screen: 90em;
    --max-area: 80em;
  }
}