.scroll-top {
  --scroll-top-bottom: 24px;
  position: fixed;
  z-index: 1100;
  right: max(24px, env(safe-area-inset-right));
  bottom: calc(var(--scroll-top-bottom) + env(safe-area-inset-bottom));
  display: grid;
  width: 45px;
  height: 45px;
  padding: 0;
  place-items: center;
  border: 1px solid rgba(39, 125, 243, .32);
  border-radius: 50%;
  background: rgba(255, 255, 255, .94);
  color: #2563eb;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  visibility: hidden;
  transition: opacity 180ms ease, transform 180ms ease, visibility 180ms ease, background-color 180ms ease, color 180ms ease, border-color 180ms ease;
  -webkit-tap-highlight-color: transparent;
}

.scroll-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
  visibility: visible;
}

.scroll-top:hover {
  border-color: #2563eb;
  background: #2563eb;
  color: #fff;
}

.scroll-top:active { background: #1668de; }

.scroll-top:focus-visible {
  outline: 3px solid rgba(39, 125, 243, .32);
  outline-offset: 3px;
}

.scroll-top svg {
  width: 22px;
  height: 22px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.8;
}

@media (max-width: 600px) {
  .scroll-top {
    right: max(16px, env(safe-area-inset-right));
    width: 48px;
    height: 48px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .scroll-top { transition: none; }
}