/*fèche vers le haut*/
 .btn_fleche{
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 35px;
  height: 35px;
  border-radius: 50%;
  background: var(--background-color-btn);
  color: var(--li-color);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
  opacity: 0;
  pointer-events: none;
  transform: translateY(20px);
  transition: all 0.3s ease;
  z-index: 999;
}

.btn_fleche:hover {
  background: var(--hover);
  transform: translateY(0) scale(1.08);
}

.btn_fleche.show {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}