/* botao roando */ 

  /* botão base */
#btnEntrar {
  position: relative;
  height: 45px;
  width: 100%;
  border: none;
  border-radius: 8px;
  background-color: #eba03e;
  color: white;
  font-size: 16px;
  cursor: pointer;
  overflow: hidden;
}

/* texto */
#btnEntrar .texto {
  display: inline-block;
}

/* spinner (bola rodando) */
.loader {
  width: 18px;
  height: 18px;
  border: 3px solid white;
  border-top: 3px solid transparent;
  border-radius: 50%;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  display: none;
  animation: girar 0.8s linear infinite;
}

/* animação */
@keyframes girar {
  from {
    transform: translate(-50%, -50%) rotate(0deg);
  }
  to {
    transform: translate(-50%, -50%) rotate(360deg);
  }
}

/* estado loading */
#btnEntrar.loading .texto {
  visibility: hidden;
}

#btnEntrar.loading .loader {
  display: block;
}