body {
  background-color: black;
  color: white;
  font-family: sans-serif;
  text-align: center;
  padding: 30px;
}

#fase-container {
  margin-top: 20px;
}

.subliminar {
  opacity: 0;
  animation: flash 4s infinite;
  color: red;
  font-size: 24px;
}

@keyframes flash {
  0%, 95% { opacity: 0; }
  96%, 98% { opacity: 1; }
  100% { opacity: 0; }
}