@fesjs/fes-design/es/back-top/style/index.css

fes-design for PC

.fes-back-top {
  position: fixed;
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  height: 44px;
  color: var(--f-primary-color);
  background-color: var(--f-white);
  border-radius: 22px;
  box-shadow: 0 2px 8px 0 var(--f-shadow-color);
  cursor: pointer;
}
.fes-back-top:hover {
  color: var(--f-hover-color-base);
  background-color: var(--f-hover-color-light);
}
.fes-back-top .fes-back-top-icon {
  font-size: calc(var(--f-font-size-base) + 6px);
}