/* ============================================================
   responsive.css — 阶段 19
   桌面端（≥1280px）的样式全部留在前四个文件里，这里只做收敛。
   断点：
     768–1279   单栏，但媒体仍是「主图 + 右侧缩略图列」
                （1024 硬撑两栏主图只剩 300px，比 768 的单栏还小，说不通）
     ≤767       手机：单栏 + 媒体堆叠 + 底部固定购买条 + 触控尺寸
   ============================================================ */

/* ------------------------------------------------------------
   底部固定购买条（只在 ≤767 显示，由上面的规则打开）
   ------------------------------------------------------------ */
.buy-bar {
  position: fixed;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 40;
  display: none;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 12px;
  padding: 10px 16px calc(10px + env(safe-area-inset-bottom));
  border-top: 1px solid var(--line);
  background: var(--bg);
  box-shadow: var(--shadow-bar);
  visibility: hidden;
  transform: translateY(100%);
  transition: transform .2s ease, visibility .2s ease;
}

.buy-bar--visible {
  visibility: visible;
  transform: translateY(0);
}

.buy-bar__info {
  min-width: 0;
}

.buy-bar__price {
  display: block;
  color: var(--cta-900);
  font-size: 18px;
  font-weight: 700;
  line-height: 1.2;
}

.buy-bar__note {
  display: block;
  overflow: hidden;
  color: var(--ink-2);
  font-size: var(--fs-small);
  line-height: 1.3;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.buy-bar__action {
  min-width: 148px;
  min-height: 48px;
  padding: 0 20px;
  color: var(--bg);
  border: 1px solid var(--cta-900);
  border-radius: var(--radius-sm);
  background: var(--cta-900);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
}

/* ------------------------------------------------------------
   1024–1279：仍然是双栏，但把购买栏收窄，把余量还给媒体
   ------------------------------------------------------------ */
@media (max-width: 1279px) {
  :root {
    --container: min(1600px, calc(100vw - 48px));
    --hero-gap: 32px;
    --section-pad: 56px;
  }

  .container {
    padding-right: 20px;
    padding-left: 20px;
  }

  .site-header__inner {
    gap: 24px;
  }

  .category-nav__inner,
  .section-nav__inner {
    gap: 32px;
  }
}


/* ------------------------------------------------------------
   ≤1279：单栏。两栏起点定在 1280（也就是原本的桌面目标宽度）。
   ------------------------------------------------------------ */
@media (max-width: 1279px) {
  :root {
    --container: 100%;
    --hero-gap: var(--panel-gap);
    --section-pad: 40px;
    --fs-display: 30px;
    --fs-h2: 23px;
    --panel-pad: 22px;
  }

  /* hero-main 变成透明包裹层，媒体 / 购买栏 / 卡片轨可以自由排序 */
  .product-hero {
    display: flex;
    flex-direction: column;
    /* 桌面端是 flex-start；列方向下那会让卡片轨撑到内容宽度，必须改回 stretch */
    align-items: stretch;
    gap: var(--hero-gap);
    max-width: 100%;
    padding-bottom: 32px;
  }

  .hero-main {
    display: contents;
  }

  /* 单栏顺序：图 → 买 → 配件 → 推荐（规格与卖点在首屏之下的通栏速览带里） */
  .product-media { order: 1; }
  .purchase-column { order: 2; }
  #accessory-rail { order: 3; }
  #related-rail { order: 4; }

  .overview-band {
    grid-template-columns: minmax(0, 1fr);
  }

  .purchase-column {
    width: 100%;
  }

  .hero-rail,
  .hero-rail > div,
  .model-benefits {
    min-width: 0;
    max-width: 100%;
  }

  .key-specs {
    grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  }

  .key-spec strong,
  .key-spec small {
    white-space: normal;
  }

  /* 卡片轨：横向滑动，露出下一张。
     配件卡下限 250 而不是 200——200 会把标题截成「1/4 Size Stainless…」 */
  .accessory-rail-grid {
    grid-auto-columns: minmax(250px, 1fr);
  }

  .related-rail-grid {
    grid-auto-columns: minmax(168px, 1fr);
  }

  .rail-addon-card,
  .related-rail-card {
    scroll-snap-align: start;
  }

  .spec-columns {
    grid-template-columns: minmax(0, 1fr);
    gap: 0;
  }

  .feature-bullets {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .spec-support {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
  }

  .spec-support > p {
    text-align: left;
  }

  .rich-list {
    gap: var(--space-12);
  }

  .rich-module {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-6);
    min-height: 0;
    padding: var(--space-6);
  }

  /* 单栏时图永远在文字上方，忽略桌面端的左右交替 */
  .rich-module--reverse .rich-module__media {
    order: 0;
  }

  .rich-module__copy h3 {
    font-size: 24px;
  }

  .included-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .review-card {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
  }

  .review-card__meta {
    grid-auto-flow: column;
    justify-content: start;
    align-items: baseline;
    gap: 10px;
  }

  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 32px;
  }

  /* 导航横滑，不折行 */
  .category-nav__inner,
  .section-nav__inner {
    justify-content: flex-start;
    gap: 28px;
    overflow-x: auto;
    white-space: nowrap;
    scrollbar-width: none;
  }

  .category-nav__inner::-webkit-scrollbar,
  .section-nav__inner::-webkit-scrollbar {
    display: none;
  }

  .category-nav__inner a,
  .section-nav__inner a {
    flex: 0 0 auto;
  }

  .lightbox__panel {
    grid-template-columns: minmax(0, 1fr);
    width: calc(100vw - 32px);
  }

  .lightbox__panel > img {
    grid-column: 1;
    width: 100%;
  }

  .lightbox__arrow--prev,
  .lightbox__arrow--next {
    position: absolute;
    top: 50%;
    grid-row: auto;
    transform: translateY(-50%);
  }

  .lightbox__arrow--prev { left: 8px; }
  .lightbox__arrow--next { right: 8px; }
  #lightbox-caption { grid-column: 1; }

  .modal__panel {
    width: min(460px, calc(100vw - 32px));
  }
}

/* ------------------------------------------------------------
   768–1279：单栏页面，但媒体区仍然是「主图 + 右侧缩略图列」。
   整块媒体封顶 720px 并居中——不封顶的话 1279 单栏会让主图和
   缩略图分踞左右两端，中间空出 260px。
   ------------------------------------------------------------ */
@media (min-width: 768px) and (max-width: 1279px) {
  .media-viewer,
  .media-viewer--image {
    max-width: 720px;
    margin-right: auto;
    margin-left: auto;
  }

  .media-viewer {
    grid-template-columns: minmax(0, 1fr);
  }

  .media-viewer--image {
    grid-template-columns: minmax(0, 1fr) 216px;
  }

  .media-tools,
  .media-thumbnails {
    max-height: 480px;
  }
}

/* 平板与手机：顶栏换行，搜索独占一行（1024–1279 仍走桌面式一行） */
@media (max-width: 1023px) {
  /* 用 padding-top/bottom；简写会把 .container 的左右内边距清成 0 */
  .site-header__inner {
    height: auto;
    flex-wrap: wrap;
    gap: 12px 20px;
    padding-top: 12px;
    padding-bottom: 12px;
  }

  .brand-link {
    flex: 0 0 auto;
  }

  .brand-link img {
    width: 140px;
  }

  .account-nav {
    margin-left: auto;
  }

  /* shrink 必须是 1 —— 0 会让搜索框在 360px 上撑出 22px 横向溢出 */
  .site-search {
    order: 3;
    flex: 1 1 100%;
    min-width: 0;
    height: 42px;
  }
}

/* ------------------------------------------------------------
   ≤767：媒体堆叠 —— 主图在上，缩略图变成可横滑的条
   ------------------------------------------------------------ */
@media (max-width: 767px) {
  .media-viewer,
  .media-viewer--image {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
  }

  .media-viewer--image .media-tools,
  .media-tools {
    max-height: none;
    overflow: visible;
  }

  .media-thumbnails,
  .media-thumbnails--product,
  .media-thumbnails--features,
  .media-thumbnails--dimensions,
  .media-thumbnails--video {
    display: flex;
    max-height: none;
    grid-template-columns: none;
    justify-content: flex-start;
    gap: 10px;
    padding-bottom: 4px;
    overflow-x: auto;
    overflow-y: visible;
    scroll-snap-type: x proximity;
  }

  /* 68 -> 78：格子保持正方，同时一屏仍露出 4 格多一点，横滑的意图看得出来 */
  .media-thumbnails button,
  .media-more {
    flex: 0 0 78px;
    width: 78px;
    scroll-snap-align: start;
  }

  .media-more {
    aspect-ratio: 1;
    border: 1px solid var(--line-soft);
    border-radius: var(--radius-sm);
    background: var(--bg);
  }

  .media-video-note {
    flex: 0 0 190px;
    width: 190px;
    aspect-ratio: auto;
  }

  /* Expand 收成一个方形图标格（保留键盘可达与 aria-label），主图也可直接点开 */
  .media-expand {
    flex: 0 0 78px;
    width: 78px;
    aspect-ratio: 1;
    padding: 0;
    font-size: 0;
  }

  .media-expand::after {
    content: "⤢";
    font-size: 20px;
    line-height: 1;
  }
}

/* ------------------------------------------------------------
   ≤767：手机
   ------------------------------------------------------------ */
@media (max-width: 767px) {
  :root {
    --section-pad: 32px;
    --fs-display: 25px;
    --fs-h2: 20px;
    --fs-h3: 16px;
    --panel-pad: 18px;
  }

  /* 手机上面板铺满内容宽度，页面底色只在面板之间露出来 */
  .product-header {
    padding-bottom: 16px;
  }

  .product-header h1 {
    max-width: none;
  }

  .container {
    padding-right: 16px;
    padding-left: 16px;
  }

  /* 顶栏：两行，logo + 购物车在上，搜索独占一行 */
  .utility-bar {
    height: auto;
    padding: 6px 0;
    font-size: var(--fs-small);
  }

  .utility-bar__inner {
    flex-wrap: wrap;
    justify-content: center;
    gap: 2px 12px;
    text-align: center;
  }

  .site-header__inner {
    gap: 12px;
  }

  .brand-link img {
    width: 132px;
  }

  .account-nav {
    gap: 16px;
  }

  /* 手机上账户入口收进购物车图标旁边，把宽度让给搜索 */
  .account-nav > a {
    display: none;
  }

  .cart-preview {
    width: min(320px, calc(100vw - 32px));
  }

  /* 分类导航与页内导航改横滑，不折行也不挤 */
  .category-nav__inner,
  .section-nav__inner {
    justify-content: flex-start;
    gap: 22px;
    height: 46px;
    overflow-x: auto;
    white-space: nowrap;
    scrollbar-width: none;
  }

  .category-nav__inner::-webkit-scrollbar,
  .section-nav__inner::-webkit-scrollbar {
    display: none;
  }

  .breadcrumb {
    min-height: 44px;
    overflow-x: auto;
    white-space: nowrap;
    scrollbar-width: none;
  }

  .breadcrumb::-webkit-scrollbar {
    display: none;
  }

  #overview,
  #accessory-rail,
  #related-rail,
  #specifications,
  #downloads,
  #reviews,
  #details,
  #size-comparison {
    scroll-margin-top: 60px;
  }

  .price {
    font-size: 28px;
  }

  .product-meta {
    font-size: var(--fs-small);
  }

  .rating {
    margin-left: 0;
    flex: 1 0 100%;
  }

  .coupon__row {
    flex-wrap: wrap;
    gap: 6px 10px;
  }

  .coupon__row strong {
    flex: 1 0 100%;
  }

  .countdown {
    flex-wrap: wrap;
    gap: 4px 10px;
  }

  .button,
  .quantity-stepper {
    min-height: 48px;
    height: auto;
  }

  .key-specs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 6px;
  }

  .key-spec {
    gap: 8px;
    padding: 10px;
  }

  .key-spec svg {
    width: 20px;
    height: 20px;
    flex-basis: 20px;
  }

  .key-spec strong {
    font-size: var(--fs-body);
  }

  .key-spec small {
    font-size: 11px;
  }

  .sibling-chip-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
  }

  .sibling-chip-row > div {
    flex-wrap: wrap;
  }

  .sibling-chip {
    min-height: 44px;
  }

  .included-trigger {
    grid-template-columns: 24px 1fr 16px;
    min-height: 56px;
  }

  .included-trigger span {
    grid-column: 2;
    grid-row: 2;
  }

  .media-stage {
    max-width: 100%;
    border-radius: var(--radius);
  }

  /* 四个通道压成一行横滑，省下首屏一整行高度 */
  .media-tabs {
    flex-wrap: nowrap;
    gap: 6px;
    margin-bottom: 12px;
    padding-bottom: 2px;
    overflow-x: auto;
    scrollbar-width: none;
  }

  .media-tabs::-webkit-scrollbar {
    display: none;
  }

  .media-tabs button {
    flex: 0 0 auto;
    min-height: 40px;
    padding: 0 12px;
  }

  .accessory-rail-grid {
    grid-auto-columns: minmax(240px, 78%);
  }

  .related-rail-grid {
    grid-auto-columns: minmax(140px, 44%);
  }

  .rail-heading {
    flex-wrap: wrap;
    gap: 2px 12px;
  }

  .rail-heading p {
    margin-left: 0;
  }

  h1 { font-size: 24px; }
  h2 { font-size: 20px; }

  .section-heading {
    margin-bottom: 20px;
  }

  .section-heading--split {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
  }

  .feature-bullets {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-3);
    margin-top: var(--space-6);
    padding-top: var(--space-6);
  }

  .spec-columns dl > div {
    grid-template-columns: minmax(0, 1fr);
    gap: 2px;
    padding: 11px 0;
  }

  .spec-columns dd {
    text-align: left;
  }

  /* 下载清单：按钮换到第二行，标题不再被挤成两行 */
  .document-card {
    grid-template-columns: 44px minmax(0, 1fr);
    gap: 12px;
    padding: 14px 16px;
  }

  .document-card a {
    grid-column: 2;
    justify-self: start;
    min-height: 44px;
  }

  .rich-module {
    padding: 0;
  }

  .rich-module:nth-child(even) {
    padding: var(--space-5);
  }

  .rich-module__copy h3 {
    font-size: 21px;
  }

  .rich-module__copy p {
    font-size: var(--fs-body);
  }

  .reviews-summary {
    flex-wrap: wrap;
    gap: 14px;
    margin-bottom: 20px;
  }

  .reviews-summary > div > strong {
    font-size: 34px;
  }

  .review-card {
    padding: 20px 0;
  }

  .included-drawer__panel {
    width: 100vw;
  }

  .included-drawer__header,
  .included-drawer__body {
    padding: 18px 16px;
  }

  .included-card {
    grid-template-columns: 84px minmax(0, 1fr);
    gap: 12px;
    min-height: 0;
  }

  .included-card img {
    width: 84px;
    height: 84px;
  }

  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 24px;
  }

  .site-footer {
    padding: 32px 0 18px;
  }

  .toast {
    top: 12px;
    right: 12px;
    left: 12px;
    max-width: none;
  }

  .lightbox__panel {
    width: calc(100vw - 24px);
  }

  .lightbox__close,
  .lightbox__arrow {
    width: 44px;
    height: 44px;
  }

  /* 底部固定购买条出现后，给页面和悬浮元素让出空间 */
  body {
    padding-bottom: 72px;
  }

  .demo-notes {
    bottom: 84px;
  }

  .demo-notes[open] {
    max-height: calc(70vh - 72px);
  }

  .buy-bar {
    display: grid;
  }
}

/* ------------------------------------------------------------
   ≤400：最窄档，只做防挤压
   ------------------------------------------------------------ */
/* ------------------------------------------------------------
   触控目标：单栏布局一律按触摸设备处理
   ------------------------------------------------------------ */
@media (max-width: 1279px) {
  .cart-button {
    min-height: 44px;
    padding: 0 2px;
  }

  .account-nav > a {
    display: inline-flex;
    align-items: center;
    min-height: 34px;
  }

  .category-nav__inner a,
  .section-nav__inner a {
    display: inline-flex;
    align-items: center;
    height: 100%;
  }

  .breadcrumb a,
  .breadcrumb span {
    display: inline-flex;
    align-items: center;
    min-height: 34px;
  }

  .rail-addon-add,
  .related-rail-add {
    min-height: 40px;
  }

  .rating {
    display: inline-flex;
    align-items: center;
    min-height: 32px;
  }

  .text-button {
    min-height: 40px;
    padding: 0 10px;
  }

  .section-heading--split a,
  .sibling-help a {
    display: inline-flex;
    align-items: center;
    min-height: 34px;
  }

  .footer-grid a {
    min-height: 34px;
    margin-bottom: 2px;
    padding: 6px 0;
    line-height: 1.5;
  }

  .document-card a {
    padding: 0 18px;
  }
}

@media (max-width: 400px) {
  .buy-controls {
    grid-template-columns: 104px minmax(0, 1fr);
  }

  .buy-bar__action {
    min-width: 128px;
    padding: 0 14px;
  }

  .media-tabs button {
    padding: 0 10px;
    font-size: 11px;
  }
}

/* 触控设备去掉纯 hover 才出现的装饰，避免点一下就"卡"在 hover 态 */
@media (hover: none) {
  .related-rail-card:hover {
    border-color: transparent;
    box-shadow: none;
  }

  .cart-menu:hover .cart-preview {
    visibility: hidden;
    opacity: 0;
  }

  .cart-menu:focus-within .cart-preview {
    visibility: visible;
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: .01ms !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }
}

@media (max-width: 359px) {
  .key-specs {
    grid-template-columns: minmax(0, 1fr);
  }
}