/* Make wrapper a positioning context */
.itr-wrapper {
    position: relative;
    display: inline-block;   /* keep it inline like the WP button block */
  }
  
  /* Hide the real <input type=file> but keep it clickable */
  .itr-input {
    position: absolute;
    inset: 0;                /* stretch over the button */
    opacity: 0;              /* invisible */
    cursor: pointer;
    width: 100%;
    height: 100%;
  }