.tool-shell-back {
  position: fixed;
  top: calc(env(safe-area-inset-top, 0px) + 12px);
  left: 12px;
  z-index: 2147483647;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 10px;
  border-radius: 999px;
  border: 1px solid rgba(0, 0, 0, 0.08);
  background: rgba(255, 255, 255, 0.92);
  color: rgba(17, 24, 39, 0.9);
  font-size: 12px;
  line-height: 1;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.08);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
}

.tool-shell-back:active {
  transform: scale(0.98);
}

.tool-shell-back svg {
  width: 14px;
  height: 14px;
}