pinafore/scss/themes/_scrollbars.scss

html {
  // Firefox with scrollbar config changes as of 2018-11
  scrollbar-face-color: #{$scrollbar-face};
  scrollbar-track-color: #{$scrollbar-track};
  // Firefox nightly as of 2018-11, new standard version
  // https://developer.mozilla.org/en-US/docs/Web/CSS/scrollbar-color
  scrollbar-color: #{$scrollbar-face $scrollbar-track};
}

::-webkit-scrollbar {
  width: 12px;
  height: 12px;
}

::-webkit-scrollbar-thumb {
  background: #{$scrollbar-face};
  border-radius: 0;
}

::-webkit-scrollbar-thumb:hover {
  background: #{$scrollbar-face-hover};
}

::-webkit-scrollbar-thumb:active {
  background: #{$scrollbar-face-active};
}

::-webkit-scrollbar-track, ::-webkit-scrollbar-track:hover, ::-webkit-scrollbar-track:active {
  background: #{$scrollbar-track};
}

::-webkit-scrollbar-corner {
  background: transparent;
}