/* ==========================================================================
   Scroll-to-Top — fixed bottom-right square, lime, slide-in after scroll
   ========================================================================== */

.scroll-top {
  position: fixed;
  right: calc(var(--gutter) + var(--safe-right));
  bottom: calc(var(--gutter) + var(--safe-bottom));
  z-index: var(--z-sticky);

  width: 52px;
  height: 52px;
  display: grid;
  place-items: center;

  background-color: var(--accent);
  color: var(--ink-on-accent);
  border: 2px solid var(--stroke);
  box-shadow: var(--sh-md);
  cursor: pointer;

  font-family: var(--ff-mono);
  font-size: 22px;
  font-weight: var(--fw-black);
  line-height: 1;

  /* Hidden state — translated off-screen + invisible */
  opacity: 0;
  visibility: hidden;
  transform: translate(0, 24px);
  pointer-events: none;

  transition:
    opacity    var(--dur) var(--ease),
    transform  var(--dur) var(--ease),
    box-shadow var(--dur-quick) var(--ease),
    visibility 0s linear var(--dur);
}

.scroll-top[data-visible="true"] {
  opacity: 1;
  visibility: visible;
  transform: translate(0, 0);
  pointer-events: auto;
  transition-delay: 0s;
}

@media (hover: hover) {
  .scroll-top:hover {
    box-shadow: var(--sh-lg);
  }
}

.scroll-top:active {
  transform: translate(2px, 2px);
  box-shadow: var(--sh-press);
}

.scroll-top:focus-visible {
  outline: 3px solid var(--stroke);
  outline-offset: 4px;
}

/* The arrow icon — pure CSS so we don't need an external icon font */
.scroll-top::before {
  content: "↑";
  display: inline-block;
}