#matrix-rain {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
}

/* 字母雨动画效果 */
@keyframes flicker {
  0% {
    opacity: 1;
  }
  50% {
    opacity: 0.8;
  }
  100% {
    opacity: 1;
  }
}

.matrix-character {
  animation: flicker 2s infinite;
}