.lab-return {
  position: fixed;
  right: max(12px, env(safe-area-inset-right));
  bottom: max(12px, env(safe-area-inset-bottom));
  z-index: 1000;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 999px;
  background: rgba(10, 18, 30, 0.78);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  padding: 8px 14px;
  color: #f7f8fb;
  font: 600 10px/1 ui-monospace, "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.14em;
  text-decoration: none;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  -webkit-tap-highlight-color: transparent;
  transition: background-color 180ms ease, border-color 180ms ease;
}

.lab-return:hover,
.lab-return:focus-visible {
  border-color: rgba(255, 255, 255, 0.48);
  background: rgba(10, 18, 30, 0.94);
  outline: none;
}