.um-back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 99999;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border: none;
  border-radius: 999px;
  background: #2271b1;
  color: #fff;
  cursor: pointer;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.18);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: translateY(12px);
  transition:
    opacity 0.25s ease,
    visibility 0.25s ease,
    transform 0.25s ease,
    background-color 0.2s ease,
    box-shadow 0.2s ease;
}

.um-back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateY(0);
}

.um-back-to-top:hover,
.um-back-to-top:focus-visible {
  background: #135e96;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.22);
  outline: none;
}

.um-back-to-top-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  display: block;
}