/* Copos de nieve */
.snowflake {
  position: fixed;
  top: -10px;
  z-index: 9999;
  color: #4169E1;
  font-size: 1em;
  animation: fall linear infinite;
}

@keyframes fall {
  to {
    transform: translateY(100vh);
  }
}

.snowflake:nth-child(1) { left: 10%; animation-duration: 3s; }
.snowflake:nth-child(2) { left: 20%; animation-duration: 4s; }
.snowflake:nth-child(3) { left: 30%; animation-duration: 3.5s; }
.snowflake:nth-child(4) { left: 40%; animation-duration: 5s; }
.snowflake:nth-child(5) { left: 50%; animation-duration: 4.5s; }