message: chore: add comment for magic number
diff: @@ -27,7 +27,10 @@ function keys(breakpoints: Dict) {
  function subtract(value: string) {
  if (!value) return value
  value = px(value)
  - const factor = value.endsWith("px") ? -1 : -0.0635
  + const factor = value.endsWith("px")
  + ? -1
  + : // the equivalent of 1px in em using a 16px base
  + -0.0635
  return isNumber(value)
  ? `${value + factor}`
  : value.replace(/(\d+\.?\d*)/u, (m) => `${parseFloat(m) + factor}`)
  