.oModal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.8);

  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

/* activation */
.oModal:target {
  opacity: 1;
  pointer-events: auto;
}

/* IMPORTANT : zone scroll */
.omodal-dialog {
  position: relative;
  width: 95%;
  max-width: 95%;
  max-height: 95vh;   /* 👈 crucial */
  margin: 2vh auto;

  background: #eee;
  border-radius: 5px;

  overflow-y: auto;   /* 👈 scroll ici */
  padding: 8px;
}