.io-left, .io-right, .io-up, .io-down {
    opacity: 0;
    transition: opacity 0.6s ease, transform 0.6s ease;
  }
  
  .io-left {
    transform: translateX(-30px);
  }
  .io-right {
    transform: translateX(30px);
  }
  .io-up {
    transform: translateY(30px);
  }
  .io-down {
    transform: translateY(-30px);
  }
  
  .io-left.visible,
  .io-right.visible,
  .io-up.visible,
  .io-down.visible {
    opacity: 1;
    transform: translate(0, 0);
  }

  .io-left {
    animation: slideInLeft 0.4s ease-out;
  }
  
  @keyframes slideInLeft {
    from {
      opacity: 0;
      transform: translateX(-30px);
    }
    to {
      opacity: 1;
      transform: translateX(0);
    }
  }