.contenedor {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.letra-giratoria {
    font-family: Montserrat, sans-serif;
    font-size: 50px;
    font-weight: 400;
    letter-spacing: -1px;
    color: rgb(126, 90, 90);
    margin: 0px 0px 22px;  
  text-shadow: 5px 5px 10px rgba(0, 0, 0, 0.3);
  display: inline-block;
  animation: girar 2s linear infinite;
}

@keyframes girar {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}
@media only screen and (max-width: 767px) {
  .letra-giratoria{ font-size:28px;}
}