.slide-in-element {
  opacity: 0;
  transform: translateX(-50vw); /* Start 100px to the left */
  transition: opacity 0.5s ease-out, transform 0.5s ease-out; /* Smooth transition */
}

/* Class added by JavaScript when in view */
.slide-in-element.is-visible {
  opacity: 1;
  transform: translateX(0); /* Slide to original position */
}