ShadowFox/userContent-files/webextension-tweaks/dark_mode.css

/*! Alters the webextension Dark Mode
  IMPORTANT: change the Internal UUID */
@-moz-document url-prefix("moz-extension://dark_mode_UUID/") {
  .comment {
    color: var(--accent-1)!important
  }
  label {
    color: var(--tone-4)!important
  }
}