message: fix(demo): use device bar fill that looks good on dark bgs too
diff: .docs-demo-device.md .docs-demo-device__md-bar {
  display: block;
  - fill: #090a0d;
  - opacity: 0.1;
  + fill: rgba(125, 125, 125, 0.3);
  padding: 0.5rem 0.75rem;
  position: relative;
  width: 100%;
  