.back-to-top {
  position: fixed;
  right: 28px;
  bottom: 28px;
  z-index: 50;
  width: 50px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  border: 1px solid var(--silver-500);
  padding: 0;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease, border-color 0.2s ease;
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  border-color: var(--white);
}

.back-to-top img {
  display: block;
  width: 24px;
  height: 24px;
}

@media (max-width: 900px) {
  .back-to-top {
    right: 16px;
    bottom: 16px;
    width: 44px;
    height: 44px;
  }

  .back-to-top img {
    width: 20px;
    height: 20px;
  }
}