/* Shared Back button (Drue 111126).
   Default style is the straight-arrow pair:
     img/ui/back-button.png         — black, normal
     img/ui/back-button-active.png  — blue, pressed
   Alternate (included, not used yet): data-back-style="return"
     img/ui/return-button.png
     img/ui/return-button-active.png
   Swap a spot later by changing data-back-style on the .ui-back element. */

.ui-back {
  position: relative;
  display: inline-block;
  width: 65px;
  height: 65px;
  padding: 0;
  margin: 0;
  border: 0;
  background: transparent;
  cursor: pointer;
  line-height: 0;
  -webkit-tap-highlight-color: transparent;
  appearance: none;
  -webkit-appearance: none;
  flex: 0 0 auto;
  vertical-align: middle;
  text-decoration: none;
}

.ui-back-img {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  pointer-events: none;
  user-select: none;
}

.ui-back-img--active { opacity: 0; }
.ui-back-img--normal { opacity: 1; }

.ui-back:active .ui-back-img--active,
.ui-back.is-pressed .ui-back-img--active { opacity: 1; }
.ui-back:active .ui-back-img--normal,
.ui-back.is-pressed .ui-back-img--normal { opacity: 0; }

/* Don't inherit the text-link chrome from nav or .back-link */
nav a.ui-back,
.back-link a.ui-back {
  color: inherit;
  border-bottom: 0;
  padding: 0;
}
nav a.ui-back:hover,
.back-link a.ui-back:hover { color: inherit; }
nav { align-items: center; }