.button-theme {
  width: 4rem;
  height: 4rem;
  margin: 0;
  padding: 0;
  /*border-radius: 50%;*/
  border: none;
  top: 10%;
  right: 5%;
  position: fixed;
  background-color: transparent;
  background-position: center;
  background-size: cover;
  background-repeat: no-repeat;
  z-index: 1;
  cursor: pointer;
}

.button-theme:focus {
  outline: none;
  border: none;
}

.button-theme-dark { 
  background-image: url("/statics/images/icons/lua-crescente.png");
}

.button-theme-light {
  background-image: url("/statics/images/icons/sol-amarelo.png");
}

@media (max-width: 600px) {
  .button-theme {
    width: 3rem;
    height: 3rem;
  }
}

@media (max-width: 500px) {
  .button-theme {
    width: 2rem;
    height: 2rem;
  }
}

@media (max-width: 400px) {
  .button-theme {
    width: 2rem;
    height: 2rem;
  }
}