/* The container must be positioned relative: */
.custom-select {
  position: relative;
}

.custom-select select {
  display: none; /*hide original SELECT element: */
}

/* Style items (options): */
.select-items {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  z-index: 99;
}

/* Hide the items when the select box is closed: */
.select-hide {
  display: none;
}