#up-flecha a {
  z-index: 2; 
  position: fixed; bottom: 15px; right: 14%;
  display: flex; justify-content: center; align-items: center;
  width: 45px; height: 45px;
  color: var(--blanco);
  background-color: var(--red);
  transition: all .3s ease;
  border: 1px solid #ddd;
  border-radius: .5em;
  transition: all 400ms;
	}
    #up-flecha a:hover{
    transition: all .1s ease;
    color: #fff;
    background-color: var(--brown);
}
  #up-flecha img{
    width: 20px;
    height: 20px;
    margin-bottom: -5px;
    }