@charset "UTF-8";
/* ============================================================
   回到頂端按鈕（.ntop）
   - 外觀沿用 product_intro 的 .top（固定右下、半透明藍圓鈕）
   - 行為：捲動後才淡入顯示，回到頂端後淡出隱藏（由 JS 切換 is-show）
   - 對應結構：index.html 內的 <a class="ntop" id="ntop">
   ============================================================ */
.ntop {
  position: fixed;
  right: 35px;
  bottom: 130px;
  width: 3rem;
  height: 3rem;
  padding: 0.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255, 255, 255, 0.9);
  border-radius: 50%;
  background-color: rgba(83, 171, 242, 0.7);
  z-index: 1000;
  transition: opacity 0.3s ease, visibility 0.3s ease, background-color 0.3s ease, color 0.3s ease;
  /* 預設隱藏，捲動後由 JS 加上 is-show 才顯示 */
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}
.ntop.is-show {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}
.ntop:hover,
.ntop:focus {
  color: #fff;
  background-color: #53abf2;
}

@media (max-width: 768px) {
  .ntop {
    right: 30px;
    bottom: 120px;
  }
}
@media (max-width: 767.98px) {
  .ntop {
    right: 12px;
    bottom: 40px;
    width: 2rem;
    height: 2rem;
    padding: 0.25rem;
  }
}