let startX;  // Posizione iniziale del tocco
const swipeThreshold = 90; // Riduce la sensibilità: richiede uno swipe più lungo
  if (Math.abs(diffX) > swipeThreshold) { // Soglia del movimento per cambiare slide
  const previousSlide = slides[currentSlideIndex];
  const outgoingClass = step > 0 ? 'swipe-left' : 'swipe-right';

  if (previousSlide) {
    previousSlide.classList.remove('swipe-left', 'swipe-right', 'swipe-enter', 'from-left', 'from-right');
    previousSlide.classList.add(outgoingClass);
    previousSlide.addEventListener('animationend', () => {
      previousSlide.classList.remove('swipe-left', 'swipe-right');
    }, { once: true });
  }

  const incomingSlide = slides[currentSlideIndex];
  if (incomingSlide) {
    incomingSlide.classList.remove('swipe-left', 'swipe-right', 'swipe-enter', 'from-left', 'from-right');
    void incomingSlide.offsetWidth; // Force reflow to restart animation
    incomingSlide.classList.add('swipe-enter', step > 0 ? 'from-right' : 'from-left');
    incomingSlide.addEventListener('animationend', () => {
      incomingSlide.classList.remove('swipe-enter', 'from-left', 'from-right');
    }, { once: true });
  }

  carousel.style.transition = "transform 0.45s ease";
  transition: transform 0.45s ease, opacity 0.45s ease, box-shadow 0.45s ease;
}

.book.swipe-left {
  animation: swipeOutLeft 0.45s ease forwards;
}

.book.swipe-right {
  animation: swipeOutRight 0.45s ease forwards;
}

.book.swipe-enter {
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.18);
}

.book.swipe-enter.from-right {
  animation: swipeEnterFromRight 0.5s ease both;
}

.book.swipe-enter.from-left {
  animation: swipeEnterFromLeft 0.5s ease both;
}

@keyframes swipeOutLeft {
  to {
    transform: translateX(-35%) rotate(-6deg) scale(0.95);
    opacity: 0;
  }
}

@keyframes swipeOutRight {
  to {
    transform: translateX(35%) rotate(6deg) scale(0.95);
    opacity: 0;
  }
}

@keyframes swipeEnterFromRight {
  from {
    transform: translateX(40%) rotate(5deg);
    opacity: 0;
  }
  to {
    transform: translateX(0) rotate(0deg);
    opacity: 1;
  }
}

@keyframes swipeEnterFromLeft {
  from {
    transform: translateX(-40%) rotate(-5deg);
    opacity: 0;
  }
  to {
    transform: translateX(0) rotate(0deg);
    opacity: 1;
  }