antd/lib/back-top/style/index.css

An enterprise-class UI design language and React-based implementation

.ant-back-top {
  z-index: 10;
  position: fixed;
  right: 100px;
  bottom: 50px;
  height: 40px;
  width: 40px;
  cursor: pointer;
}
.ant-back-top-content {
  height: 40px;
  width: 40px;
  border-radius: 20px;
  background-color: rgba(64, 64, 64, 0.4);
  color: #fff;
  text-align: center;
  -webkit-transition: all 0.3s cubic-bezier(0.645, 0.045, 0.355, 1);
  transition: all 0.3s cubic-bezier(0.645, 0.045, 0.355, 1);
}
.ant-back-top-content:hover {
  background-color: rgba(64, 64, 64, 0.6);
  -webkit-transition: all 0.3s cubic-bezier(0.645, 0.045, 0.355, 1);
  transition: all 0.3s cubic-bezier(0.645, 0.045, 0.355, 1);
}
.ant-back-top-icon {
  font-size: 20px;
  margin-top: 10px;
}