.back-to-top {
  position: fixed;
  z-index: 80;
  right: max(24px, calc((100vw - 1180px) / 2 - 64px));
  bottom: 30px;
  display: flex;
  width: 46px;
  height: 46px;
  align-items: center;
  justify-content: center;
  padding: 0;
  border: 1px solid rgb(255 255 255 / 72%);
  border-radius: 50%;
  background: linear-gradient(145deg, #e23b27, #f4772d);
  box-shadow: 0 5px 16px rgb(168 49 26 / 28%);
  color: #fff;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(12px);
  transition: opacity .2s ease, transform .2s ease, box-shadow .2s ease;
}

.back-to-top.is-visible {
  opacity: .92;
  pointer-events: auto;
  transform: translateY(0);
}

.back-to-top:hover {
  opacity: 1;
  box-shadow: 0 7px 20px rgb(168 49 26 / 38%);
  transform: translateY(-2px);
}

.back-to-top:focus-visible {
  outline: 3px solid rgb(226 59 39 / 24%);
  outline-offset: 3px;
}

.back-to-top svg {
  width: 24px;
  height: 24px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 2;
}

@media (max-width: 1280px) {
  .back-to-top { right: 18px; bottom: 22px; }
}