.back-to-top {
  position: fixed;
  right: max(20px, env(safe-area-inset-right));
  bottom: max(20px, env(safe-area-inset-bottom));
  z-index: 20;
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  padding: 0;
  border: 1px solid #fff;
  border-radius: 4px;
  background: #990100;
  color: #fff;
  box-shadow: 0 2px 8px rgb(0 0 0 / 18%);
  cursor: pointer;
}

.back-to-top::before {
  content: "";
  width: 20px;
  height: 16px;
  background: url("../images/common/icon-arrow.svg") center / contain no-repeat;
  transform: rotate(-90deg);
}

.back-to-top:hover {
  background: #710100;
}

.back-to-top:focus-visible {
  outline: 3px solid #222;
  outline-offset: 3px;
}

.back-to-top[hidden],
body.is-menu-open .back-to-top {
  display: none;
}