.scroll-to-top-btn {
  position: fixed;
  right: clamp(1rem, 3vw, 1.75rem);
  bottom: clamp(1rem, 3vw, 1.75rem);
  z-index: 9995;
  width: 52px;
  height: 52px;
  border: 1px solid rgba(255, 0, 255, 0.45);
  border-radius: 50%;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  background: linear-gradient(
    145deg,
    rgba(255, 0, 255, 0.35) 0%,
    rgba(0, 255, 255, 0.18) 100%
  );
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.1),
    0 6px 28px rgba(255, 0, 255, 0.28),
    0 4px 16px rgba(0, 0, 0, 0.4);
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px) scale(0.92);
  transition:
    opacity 0.28s ease,
    visibility 0.28s ease,
    transform 0.28s cubic-bezier(0.34, 1.2, 0.64, 1),
    border-color 0.2s ease,
    box-shadow 0.2s ease;
  pointer-events: none;
}

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

.scroll-to-top-btn:hover {
  border-color: rgba(0, 255, 255, 0.6);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.14),
    0 10px 36px rgba(255, 0, 255, 0.38),
    0 6px 20px rgba(0, 255, 255, 0.15);
  transform: translateY(-3px) scale(1);
}

.scroll-to-top-btn:active {
  transform: translateY(-1px) scale(0.96);
}

.scroll-to-top-btn:focus-visible {
  outline: 2px solid rgba(0, 255, 255, 0.7);
  outline-offset: 3px;
}

.scroll-to-top-btn svg {
  width: 22px;
  height: 22px;
  pointer-events: none;
}

@media (max-width: 768px) {
  .scroll-to-top-btn {
    width: 46px;
    height: 46px;
    right: 1rem;
    bottom: 1rem;
  }
}