/* プレイ中の戻る操作を、全ゲームで左上の横並びに統一する。 */
.game-navigation-unified {
  position: absolute;
  z-index: 30;
  top: 96px;
  left: max(18px, calc(50% - 590px));
  display: flex;
  align-items: center;
  gap: 8px;
}

.game-navigation-unified button {
  min-height: 42px;
  padding: 9px 14px;
  border: 1px solid #b9d8d2;
  border-radius: 12px;
  background: #fff;
  color: #075f58;
  font: inherit;
  font-size: 14px;
  font-weight: 700;
  line-height: 1.25;
  cursor: pointer;
  white-space: nowrap;
}

.game-navigation-unified button:hover {
  border-color: #138476;
  background: #f0faf7;
}

.game-navigation-unified button:focus-visible {
  outline: 3px solid rgba(19, 132, 118, 0.3);
  outline-offset: 2px;
}

/* 元のボタンは機能を残したまま隠し、二重表示を防ぐ。 */
main:has(.game-navigation-unified) > .difficulty-return,
main:has(.game-navigation-unified) .change-top > .back-button {
  visibility: hidden !important;
}

@media (max-width: 720px) {
  .game-navigation-unified {
    top: 88px;
    left: 14px;
    right: 14px;
    gap: 6px;
  }

  .game-navigation-unified button {
    min-height: 40px;
    padding: 8px 10px;
    font-size: 13px;
  }
}

@media (max-width: 410px) {
  .game-navigation-unified {
    gap: 5px;
  }

  .game-navigation-unified button {
    padding-inline: 8px;
    font-size: 12px;
  }
}