/* ==========================================================================
   Ossuno — 官网设计系统
   参考 Apple 产品页体系：安静的大留白、精确字阶、材质与克制的动效。
   动效由 CSS 滚动驱动；仅下载芯片识别使用渐进增强 JavaScript。
   ========================================================================== */

/* ---------------------------------------------------------------
   1. 设计令牌
   --------------------------------------------------------------- */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "PingFang SC", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  /* 亮色主题 — Apple 画布色 */
  --bg: #f5f5f7;
  --surface: #ffffff;
  --ink: #1d1d1f;
  --ink-2: #515154;
  --ink-3: #86868b;
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --accent-ink: #0066cc;
  --accent-soft: rgba(0, 113, 227, 0.1);
  --hairline: rgba(0, 0, 0, 0.09);
  --hairline-strong: rgba(0, 0, 0, 0.14);

  /* 纯黑叙事带 — 两种主题下都保持黑色（Apple Pro 页做法） */
  --band-bg: #000000;
  --band-ink: #f5f5f7;
  --band-ink-2: #a1a1a6;
  --band-accent: #2997ff;
  --band-hairline: rgba(255, 255, 255, 0.12);
  --band-card: rgba(255, 255, 255, 0.045);
  --band-card-border: rgba(255, 255, 255, 0.1);

  /* 玻璃导航 */
  --header-bg: rgba(246, 246, 248, 0.78);
  --header-line: rgba(0, 0, 0, 0.08);

  /* 卡片（亮色区域） */
  --card: #ffffff;
  --card-border: rgba(0, 0, 0, 0.08);
  --card-row-line: rgba(0, 0, 0, 0.05);
  --card-shadow: 0 24px 70px rgba(29, 29, 31, 0.1), 0 4px 14px rgba(29, 29, 31, 0.05);

  /* 组件语义色 */
  --folder: #3ea7f0;
  --folder-deep: #2b8fd9;
  --ok: #30a14e;
  --ok-soft: rgba(48, 161, 78, 0.12);

  /* 动效曲线 — Apple 关键帧（临界阻尼） */
  --ease-apple: cubic-bezier(0.32, 0.72, 0, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --dur: 0.7s;

  /* 布局 */
  --wide: min(1200px, 100% - 48px);
  --read: min(720px, 100% - 48px);

  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101013;
    --surface: #1a1a1e;
    --ink: #f5f5f7;
    --ink-2: #c7c7cc;
    --ink-3: #8e8e93;
    --accent: #2997ff;
    --accent-hover: #3da2ff;
    --accent-ink: #6cb2ff;
    --accent-soft: rgba(41, 151, 255, 0.16);
    --hairline: rgba(255, 255, 255, 0.1);
    --hairline-strong: rgba(255, 255, 255, 0.16);
    --band-bg: #000000;
    --band-card: rgba(255, 255, 255, 0.05);
    --band-card-border: rgba(255, 255, 255, 0.1);
    --header-bg: rgba(16, 16, 19, 0.72);
    --header-line: rgba(255, 255, 255, 0.09);
    --card: #1c1c20;
    --card-border: rgba(255, 255, 255, 0.09);
    --card-row-line: rgba(255, 255, 255, 0.055);
    --card-shadow: 0 24px 70px rgba(0, 0, 0, 0.5), 0 4px 14px rgba(0, 0, 0, 0.4);
    color-scheme: dark;
  }
}

/* ---------------------------------------------------------------
   2. 基础
   --------------------------------------------------------------- */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.7;
  letter-spacing: -0.011em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: inherit;
  text-decoration: none;
}

.product-name {
  white-space: nowrap;
}

h1,
h2,
h3 {
  margin: 0;
  font-weight: 720;
  letter-spacing: -0.032em;
}

:target {
  scroll-margin-top: 84px;
}

:focus-visible {
  outline: 3px solid rgba(0, 113, 227, 0.45);
  outline-offset: 4px;
  border-radius: 8px;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 100;
  padding: 10px 16px;
  color: #fff;
  background: var(--ink);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  translate: 0 -200%;
  transition: translate 0.2s var(--ease-apple);
}

.skip-link:focus {
  translate: 0 0;
}

/* ---------------------------------------------------------------
   3. 玻璃导航
   --------------------------------------------------------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--header-bg);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
}

/* 滚动后浮现发丝线 — 纯 CSS 滚动时间线驱动 */
@supports (animation-timeline: scroll()) {
  .site-header {
    animation: header-line 1s linear both;
    animation-timeline: scroll();
    animation-range: 0 96px;
  }
}

@keyframes header-line {
  to {
    box-shadow: 0 1px 0 var(--header-line);
  }
}

.header-inner {
  width: var(--wide);
  min-height: 56px;
  margin-inline: auto;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  width: fit-content;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.brand img {
  width: 26px;
  height: 26px;
  border-radius: 7px;
  box-shadow: 0 2px 8px rgba(29, 29, 31, 0.18);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 30px;
  font-size: 13px;
  font-weight: 530;
  color: var(--ink-2);
}

.main-nav a,
.site-footer nav a {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  transition: color 0.18s ease;
}

.main-nav a:hover,
.site-footer nav a:hover {
  color: var(--ink);
}

.main-nav [aria-current="page"] {
  color: var(--ink);
}

/* 导航下载胶囊 */
.header-download {
  justify-self: end;
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0 18px;
  color: #fff;
  background: var(--accent);
  border-radius: 999px;
  font-size: 13px;
  font-weight: 590;
  white-space: nowrap;
  transition: background 0.2s ease, transform 0.2s var(--ease-apple);
}

.header-download:hover {
  background: var(--accent-hover);
}

.header-download:active {
  transform: scale(0.96);
}

/* ---------------------------------------------------------------
   4. 按钮
   --------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-height: 50px;
  padding: 0 30px;
  border-radius: 980px; /* Apple 药丸 */
  border: 0;
  font-size: 17px;
  font-weight: 590;
  letter-spacing: -0.01em;
  white-space: nowrap;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, transform 0.2s var(--ease-apple),
    box-shadow 0.2s ease;
}

.btn:active {
  transform: scale(0.965); /* 按压即时反馈 */
}

.btn-primary {
  color: #fff;
  background: var(--accent);
  box-shadow: 0 8px 22px rgba(0, 113, 227, 0.26);
}

.btn-primary:hover {
  background: var(--accent-hover);
  box-shadow: 0 10px 26px rgba(0, 113, 227, 0.32);
}

.on-dark .btn-primary {
  background: var(--band-accent);
  color: #04121f;
  box-shadow: 0 8px 24px rgba(41, 151, 255, 0.35);
}

.on-dark .btn-primary:hover {
  background: #4daaff;
}

.btn-ghost {
  color: var(--accent-ink);
  background: transparent;
  padding-inline: 14px;
}

.btn-ghost:hover {
  text-decoration: underline;
  text-underline-offset: 5px;
}

.on-dark .btn-ghost {
  color: var(--band-accent);
}

/* 「进一步了解 ›」式文本链接 */
.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: var(--accent-ink);
  font-size: 17px;
  font-weight: 590;
}

.on-dark .link-arrow {
  color: var(--band-accent);
}

.link-arrow::after {
  content: "›";
  font-size: 1.25em;
  line-height: 1;
  transition: translate 0.22s var(--ease-apple);
}

.link-arrow:hover::after {
  translate: 3px 0;
}

.link-arrow:hover {
  text-decoration: underline;
  text-underline-offset: 5px;
}

.text-link {
  color: var(--accent-ink);
  font-weight: 590;
}

.text-link:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

/* ---------------------------------------------------------------
   5. 首屏
   --------------------------------------------------------------- */

.hero {
  overflow: clip;
  padding: 104px 0 0;
  text-align: center;
}

.hero-inner {
  width: min(880px, 100% - 48px);
  margin-inline: auto;
}

.hero-icon {
  width: 104px;
  height: 104px;
  margin: 0 auto 30px;
  border-radius: 26px;
  filter: drop-shadow(0 20px 34px rgba(21, 45, 94, 0.22));
}

.hero h1 {
  font-size: clamp(46px, 7vw, 88px);
  font-weight: 760;
  line-height: 1.1;
  letter-spacing: -0.042em;
}

/* 渐变强调 — Apple「耀眼」字效，蓝色系呼应应用图标 */
.hero h1 em {
  font-style: normal;
  color: var(--accent-ink);
  background: linear-gradient(96deg, var(--accent) 8%, #2997ff 52%, #5ac8fa 96%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

@supports not ((-webkit-background-clip: text) or (background-clip: text)) {
  .hero h1 em {
    background: none;
    color: var(--accent-ink);
  }
}

.hero-lead {
  max-width: 620px;
  margin: 26px auto 0;
  color: var(--ink-2);
  font-size: clamp(18px, 2.2vw, 22px);
  line-height: 1.62;
  letter-spacing: -0.014em;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 10px 22px;
  margin-top: 36px;
}

.hero-meta {
  margin: 22px 0 0;
  color: var(--ink-3);
  font-size: 13px;
}

.hero-meta a {
  color: var(--accent-ink);
  font-weight: 590;
  text-decoration: underline;
  text-decoration-color: rgba(0, 102, 204, 0.28);
  text-underline-offset: 3px;
}

.distribution-summary {
  max-width: 660px;
  margin: 14px auto 0;
  padding: 10px 14px;
  color: var(--ink-2);
  background: rgba(215, 122, 0, 0.08);
  border: 1px solid rgba(215, 122, 0, 0.22);
  border-radius: 12px;
  font-size: 12px;
  line-height: 1.55;
}

.distribution-summary strong {
  color: #b86400;
  font-weight: 680;
}

.distribution-summary a {
  color: var(--accent-ink);
  font-weight: 590;
  text-decoration: underline;
  text-underline-offset: 3px;
}

@media (prefers-color-scheme: dark) {
  .distribution-summary {
    background: rgba(255, 159, 10, 0.1);
    border-color: rgba(255, 159, 10, 0.24);
  }

  .distribution-summary strong {
    color: #ffb340;
  }
}

.architecture-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px 10px;
  margin: 13px 0 0;
  color: var(--ink-3);
  font-size: 12px;
}

.architecture-links a {
  color: var(--accent-ink);
  font-weight: 590;
  text-decoration: underline;
  text-decoration-color: rgba(0, 102, 204, 0.28);
  text-underline-offset: 3px;
}

.final .architecture-links {
  justify-content: center;
}

/* 主截图 — 深阴影窗口 + 底部辉光 */
.hero-shot {
  position: relative;
  width: min(1080px, calc(100% - 40px));
  margin: 72px auto 0;
}

.hero-shot::before {
  content: "";
  position: absolute;
  inset: -90px -18% -160px;
  z-index: -1;
  background:
    radial-gradient(46% 60% at 34% 42%, rgba(0, 113, 227, 0.16), transparent 68%),
    radial-gradient(40% 52% at 70% 56%, rgba(90, 200, 250, 0.15), transparent 70%);
  filter: blur(6px);
}

.hero-shot-frame {
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  box-shadow: 0 60px 140px rgba(15, 23, 42, 0.22), 0 12px 34px rgba(15, 23, 42, 0.1);
}

.hero-shot-frame img {
  width: 100%;
}

.hero-shot::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 180px;
  background: linear-gradient(to top, var(--bg), transparent);
  pointer-events: none;
}

/* ---------------------------------------------------------------
   6. 章节骨架
   --------------------------------------------------------------- */

.section {
  padding: 128px 0;
}

.on-light-alt {
  background: var(--surface);
}

.on-dark {
  background: var(--band-bg);
  color: var(--band-ink);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.06), inset 0 -1px 0 rgba(255, 255, 255, 0.06);
}

.inner {
  width: var(--wide);
  margin-inline: auto;
}

.kicker {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 0 0 18px;
  color: var(--accent-ink);
  font-size: 15px;
  font-weight: 640;
  letter-spacing: 0.01em;
}

.on-dark .kicker {
  color: var(--band-accent);
}

.kicker::before {
  content: "";
  width: 22px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  opacity: 0.55;
}

.section-title {
  max-width: 640px;
  font-size: clamp(36px, 4.6vw, 60px);
  font-weight: 740;
  line-height: 1.14;
  letter-spacing: -0.035em;
}

.section-lead {
  max-width: 560px;
  margin: 22px 0 0;
  color: var(--ink-2);
  font-size: 19px;
  line-height: 1.68;
}

.on-dark .section-lead {
  color: var(--band-ink-2);
}

/* 章节主体：文案 + 可视化 */
.chapter-body {
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(0, 1.14fr);
  align-items: center;
  gap: clamp(48px, 6vw, 96px);
  margin-top: 64px;
}

.chapter-body.flip .chapter-copy {
  order: 2;
}

/* 快捷键 / 要点清单 */
.plain-list {
  margin: 36px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--hairline);
}

.on-dark .plain-list {
  border-top-color: var(--band-hairline);
}

.plain-list li {
  display: flex;
  align-items: center;
  gap: 16px;
  min-height: 52px;
  border-bottom: 1px solid var(--hairline);
  color: var(--ink-2);
  font-size: 14.5px;
}

.on-dark .plain-list li {
  border-bottom-color: var(--band-hairline);
  color: var(--band-ink-2);
}

.plain-list kbd {
  min-width: 72px;
  padding: 4px 9px;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--card-border);
  border-bottom-width: 2px;
  border-radius: 7px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 620;
  text-align: center;
  box-shadow: 0 1px 2px rgba(29, 29, 31, 0.06);
}

.on-dark .plain-list kbd {
  color: var(--band-ink);
  background: rgba(255, 255, 255, 0.07);
  border-color: rgba(255, 255, 255, 0.14);
  box-shadow: none;
}

/* ---------------------------------------------------------------
   7. 可视化卡片（通用）
   --------------------------------------------------------------- */

.visual-card {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 22px;
  box-shadow: var(--card-shadow);
  overflow: hidden;
}

.on-dark .visual-card {
  background: var(--band-card);
  border-color: var(--band-card-border);
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.55);
  -webkit-backdrop-filter: blur(24px);
  backdrop-filter: blur(24px);
}

/* 卡片标题栏（路径行 / 窗口标题） */
.visual-head {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 52px;
  padding: 0 18px;
  border-bottom: 1px solid var(--card-border);
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--ink-3);
}

.on-dark .visual-head {
  border-bottom-color: var(--band-card-border);
  color: var(--band-ink-2);
}

.visual-head strong {
  color: var(--ink);
  font-weight: 620;
}

.on-dark .visual-head strong {
  color: var(--band-ink);
}

.visual-head .spacer {
  margin-left: auto;
}

/* 对象行 */
.object-row {
  display: grid;
  grid-template-columns: 26px 1fr auto;
  align-items: center;
  gap: 12px;
  min-height: 54px;
  padding: 0 18px;
  border-bottom: 1px solid var(--card-row-line);
  font-size: 14px;
}

.on-dark .object-row {
  border-bottom-color: rgba(255, 255, 255, 0.06);
}

.object-row:last-child {
  border-bottom: 0;
}

.object-row small {
  color: var(--ink-3);
  font-size: 12px;
  font-family: var(--font-mono);
}

.on-dark .object-row small {
  color: var(--band-ink-2);
}

.object-row.selected {
  color: #fff;
  background: var(--accent);
  border-radius: 10px;
  border-bottom-color: transparent;
}

.object-row.selected small {
  color: rgba(255, 255, 255, 0.78);
}

.object-kind {
  position: relative;
  width: 20px;
  height: 16px;
  border-radius: 3.5px;
}

.folder-kind {
  background: linear-gradient(180deg, var(--folder), var(--folder-deep));
  box-shadow: inset 0 -3px 0 rgba(4, 74, 122, 0.22);
}

.folder-kind::before {
  content: "";
  position: absolute;
  top: -4px;
  left: 2px;
  width: 9px;
  height: 5px;
  background: inherit;
  border-radius: 2.5px 2.5px 0 0;
}

.file-kind {
  width: 15px;
  height: 19px;
  margin-left: 2px;
  background: var(--surface);
  border: 1.5px solid var(--ink-3);
  border-radius: 3px;
}

.on-dark .file-kind {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--band-ink-2);
}

/* ---------------------------------------------------------------
   8. 整理章节可视化（移动 → 撤销）
   --------------------------------------------------------------- */

.undo-card {
  padding: 44px 36px 92px;
}

.undo-scene {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 64px 1fr;
  align-items: center;
  gap: 8px;
}

.move-origin {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 14px;
  min-height: 138px;
  padding: 18px;
  background: var(--bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  text-align: center;
}

.on-dark .move-origin {
  background: rgba(255, 255, 255, 0.04);
  border-color: var(--band-card-border);
}

.move-origin.destination {
  background: var(--accent-soft);
  border-color: rgba(0, 113, 227, 0.34);
}

.move-origin p {
  margin: 0;
}

.move-origin strong {
  display: block;
  font-size: 14px;
}

.move-origin small {
  display: block;
  margin-top: 3px;
  color: var(--ink-3);
  font-size: 10.5px;
  font-family: var(--font-mono);
}

.on-dark .move-origin small {
  color: var(--band-ink-2);
}

.mini-folder {
  position: relative;
  width: 46px;
  height: 34px;
  background: linear-gradient(180deg, var(--folder), var(--folder-deep));
  border-radius: 5.5px;
  box-shadow: inset 0 -5px 0 rgba(4, 74, 122, 0.2), 0 6px 14px rgba(4, 74, 122, 0.22);
}

.mini-folder::before {
  content: "";
  position: absolute;
  top: -6px;
  left: 4px;
  width: 20px;
  height: 9px;
  background: inherit;
  border-radius: 4px 4px 0 0;
}

.move-track {
  position: relative;
  height: 1.5px;
  background: linear-gradient(90deg, transparent, var(--ink-3) 22%, var(--ink-3) 78%, transparent);
}

.on-dark .move-track {
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4) 22%, rgba(255, 255, 255, 0.4) 78%, transparent);
}

.move-track span {
  position: absolute;
  top: 50%;
  left: 50%;
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  color: var(--accent-ink);
  background: var(--surface);
  border: 1px solid var(--card-border);
  border-radius: 50%;
  font-size: 13px;
  translate: -50% -50%;
}

.on-dark .move-track span {
  color: var(--band-accent);
  background: #0b0b0d;
  border-color: var(--band-card-border);
}

.undo-banner {
  position: absolute;
  left: 50%;
  bottom: -64px;
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 46px;
  padding: 0 16px;
  color: #f5f5f7;
  background: rgba(29, 29, 31, 0.92);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 999px;
  box-shadow: 0 14px 34px rgba(0, 0, 0, 0.28);
  font-size: 12.5px;
  white-space: nowrap;
  translate: -50% 0;
}

.check-mark {
  display: grid;
  place-items: center;
  width: 18px;
  height: 18px;
  color: #fff;
  background: var(--ok);
  border-radius: 50%;
  font-size: 10px;
  font-weight: 800;
}

.undo-banner b {
  margin-left: 4px;
  color: #6cb2ff;
}

/* ---------------------------------------------------------------
   9. 传输章节可视化（黑色叙事带）
   --------------------------------------------------------------- */

.transfer-card {
  padding: 0;
}

.transfer-row {
  display: grid;
  grid-template-columns: 36px 1fr 116px;
  align-items: center;
  gap: 14px;
  min-height: 82px;
  padding: 0 20px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.transfer-row p {
  margin: 0;
  min-width: 0;
}

.transfer-row strong {
  display: block;
  font-size: 13.5px;
  font-weight: 620;
}

.transfer-row small {
  display: block;
  margin-top: 2px;
  color: var(--band-ink-2);
  font-size: 11px;
  font-family: var(--font-mono);
}

.transfer-icon {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  color: var(--band-accent);
  background: rgba(41, 151, 255, 0.12);
  border: 1px solid rgba(41, 151, 255, 0.22);
  border-radius: 9px;
  font-size: 14px;
  font-weight: 700;
}

.transfer-done {
  justify-self: end;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: #43d17c;
  font-size: 12px;
  font-weight: 590;
}

/* 进度条 — 滚入时生长（见动效系统） */
.transfer-bar {
  overflow: hidden;
  height: 5px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 999px;
}

.transfer-bar i {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, #1f8fff, #5ac8fa);
  box-shadow: 0 0 14px rgba(41, 151, 255, 0.65);
  transform: scaleX(0.68);
  transform-origin: left;
}

.transfer-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 8px;
  min-height: 64px;
  padding: 12px 20px;
  color: var(--band-ink-2);
  background: rgba(0, 0, 0, 0.35);
  font-size: 11.5px;
}

.transfer-foot .spacer {
  margin-left: auto;
}

.chip {
  padding: 5px 11px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--band-card-border);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--band-ink);
}

.chip.on {
  color: #04121f;
  background: var(--band-accent);
  border-color: transparent;
  font-weight: 640;
}

/* ---------------------------------------------------------------
   10. MCP 章节可视化
   --------------------------------------------------------------- */

.mcp-card {
  padding: 18px 18px 16px;
}

.mcp-head {
  display: flex;
  align-items: center;
  gap: 9px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--band-card-border);
  color: var(--band-ink-2);
  font-size: 12px;
  font-weight: 620;
}

.ai-mark {
  display: grid;
  place-items: center;
  width: 22px;
  height: 22px;
  color: #04121f;
  background: linear-gradient(135deg, #2997ff, #5ac8fa);
  border-radius: 7px;
  font-size: 10.5px;
  font-weight: 800;
}

.mcp-head small {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
}

.mcp-chat {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-top: 16px;
}

.mcp-bubble {
  max-width: 84%;
  padding: 11px 15px;
  border-radius: 17px;
  font-size: 13px;
  line-height: 1.62;
}

.mcp-bubble.user {
  align-self: flex-end;
  color: #04121f;
  background: linear-gradient(135deg, #2997ff, #4aa8f7);
  border-bottom-right-radius: 6px;
}

.mcp-bubble.ai {
  align-self: flex-start;
  color: var(--band-ink);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--band-card-border);
  border-bottom-left-radius: 6px;
}

.mcp-tools {
  margin: 0;
  padding: 2px 0 0;
  list-style: none;
}

.mcp-tool-row {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 40px;
  border-top: 1px dashed rgba(255, 255, 255, 0.12);
  font-size: 11.5px;
  color: var(--band-ink-2);
}

.mcp-tool-row:first-child {
  border-top: 0;
}

.mcp-tool-row code {
  color: var(--band-accent);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 640;
}

.mcp-tool-row small {
  font-family: var(--font-mono);
  font-size: 10px;
}

.tool-done {
  margin-left: auto;
  display: grid;
  place-items: center;
  width: 16px;
  height: 16px;
  color: #04121f;
  background: #43d17c;
  border-radius: 50%;
  font-size: 9px;
  font-weight: 800;
}

/* ---------------------------------------------------------------
   11. 安全章节
   --------------------------------------------------------------- */

.security-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin-top: 72px;
  border-top: 1px solid var(--hairline);
  border-left: 1px solid var(--hairline);
}

.security-grid article {
  padding: 30px 26px 34px;
  border-right: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
}

.security-grid .num {
  color: var(--ink-3);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
}

.security-grid h3 {
  margin: 40px 0 10px;
  font-size: 17.5px;
  font-weight: 680;
  letter-spacing: -0.018em;
}

.security-grid p {
  margin: 0;
  color: var(--ink-2);
  font-size: 13.5px;
  line-height: 1.66;
}

/* ---------------------------------------------------------------
   12. 开始使用（步骤轨）
   --------------------------------------------------------------- */

.steps {
  --node: 42px;
  margin: 52px 0 0;
  padding: 0;
  list-style: none;
}

.step {
  position: relative;
  display: grid;
  grid-template-columns: var(--node) minmax(0, 1fr);
  gap: 0 20px;
  padding-bottom: 38px;
}

.step:last-child {
  padding-bottom: 0;
}

.step::after {
  content: "";
  position: absolute;
  left: calc(var(--node) / 2 - 1px);
  top: calc(var(--node) + 8px);
  bottom: 6px;
  width: 2px;
  border-radius: 2px;
  background: var(--hairline-strong);
}

.step:last-child::after {
  display: none;
}

.step-num {
  display: grid;
  place-items: center;
  width: var(--node);
  height: var(--node);
  color: var(--accent-ink);
  background: var(--accent-soft);
  border-radius: 50%;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  box-shadow: 0 0 0 6px var(--bg);
}

.step-body {
  padding-top: 4px;
}

.step-body h3 {
  font-size: 17px;
  font-weight: 680;
  letter-spacing: -0.014em;
}

.step-body p {
  margin: 6px 0 0;
  color: var(--ink-2);
  font-size: 14px;
  line-height: 1.62;
  max-width: 46ch;
}

.start-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  align-items: center;
  gap: clamp(48px, 6vw, 90px);
  margin-top: 8px;
}

.install-note {
  max-width: 460px;
  margin: 26px 0 0;
  color: var(--ink-3);
  font-size: 12px;
  line-height: 1.7;
}

.account-shot {
  overflow: hidden;
  margin: 0;
  background: var(--surface);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  box-shadow: var(--card-shadow);
}

.account-shot img {
  width: 100%;
}

/* ---------------------------------------------------------------
   13. 常见问题（无 JS 手风琴）
   --------------------------------------------------------------- */

.faq-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.62fr) minmax(0, 1.38fr);
  gap: clamp(48px, 6vw, 110px);
  align-items: start;
}

.faq-list {
  border-top: 1px solid var(--hairline);
}

.faq-list details {
  border-bottom: 1px solid var(--hairline);
}

.faq-list summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  min-height: 74px;
  cursor: pointer;
  font-size: 16.5px;
  font-weight: 620;
  letter-spacing: -0.014em;
  list-style: none;
  transition: color 0.2s ease;
}

.faq-list summary::-webkit-details-marker {
  display: none;
}

.faq-list summary:hover {
  color: var(--accent-ink);
}

.faq-toggle {
  position: relative;
  flex: 0 0 30px;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  color: var(--ink-3);
  background: var(--surface);
  border: 1px solid var(--card-border);
  border-radius: 50%;
  transition: transform 0.32s var(--ease-apple), color 0.32s ease,
    background 0.32s ease, border-color 0.32s ease;
}

.faq-toggle::before,
.faq-toggle::after {
  content: "";
  grid-area: 1 / 1;
  background: currentColor;
  border-radius: 1px;
}

.faq-toggle::before {
  width: 12px;
  height: 1.6px;
}

.faq-toggle::after {
  width: 1.6px;
  height: 12px;
}

.faq-list details[open] .faq-toggle {
  color: var(--accent-ink);
  background: var(--accent-soft);
  border-color: transparent;
  transform: rotate(45deg);
}

.faq-list details p {
  max-width: 680px;
  margin: -2px 48px 26px 0;
  color: var(--ink-2);
  font-size: 14.5px;
  line-height: 1.72;
}

.faq-list details a {
  color: var(--accent-ink);
  text-decoration: underline;
  text-decoration-color: rgba(0, 102, 204, 0.3);
  text-underline-offset: 3px;
}

/* 展开高度动画 — 渐进增强（Chrome 131+），其余浏览器正常开合 */
:root {
  interpolate-size: allow-keywords;
}

.faq-list details::details-content {
  block-size: 0;
  overflow: clip;
  transition: block-size 0.42s var(--ease-apple), content-visibility 0.42s allow-discrete;
}

.faq-list details[open]::details-content {
  block-size: auto;
}

/* ---------------------------------------------------------------
   14. 结尾行动召唤
   --------------------------------------------------------------- */

.final {
  padding: 150px 0 140px;
  text-align: center;
  background:
    radial-gradient(58% 80% at 50% 0%, rgba(0, 113, 227, 0.09), transparent 70%),
    var(--surface);
}

.final-icon {
  width: 108px;
  height: 108px;
  margin: 0 auto 28px;
  border-radius: 27px;
  filter: drop-shadow(0 24px 40px rgba(21, 45, 94, 0.24));
}

.final .eyebrow-line {
  margin: 0 0 16px;
  color: var(--ink-3);
  font-size: 14px;
  font-weight: 590;
}

.final h2 {
  font-size: clamp(38px, 5vw, 64px);
  font-weight: 740;
  line-height: 1.12;
  letter-spacing: -0.038em;
}

.final .hero-actions {
  margin-top: 34px;
}

/* ---------------------------------------------------------------
   15. 页脚
   --------------------------------------------------------------- */

.site-footer {
  padding: 28px 0 40px;
  color: var(--ink-3);
  border-top: 1px solid var(--hairline);
  font-size: 12px;
}

.footer-inner {
  width: var(--wide);
  margin-inline: auto;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 24px;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  color: var(--ink-2);
  font-weight: 640;
}

.footer-brand img {
  width: 20px;
  height: 20px;
  border-radius: 5px;
}

.footer-inner > p {
  margin: 0;
}

.site-footer nav {
  justify-self: end;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 22px;
}

/* ---------------------------------------------------------------
   16. 文档页（mcp / support / privacy）
   --------------------------------------------------------------- */

.document-main {
  min-height: calc(100vh - 220px);
}

/* 居中大标题 hero — Apple 产品子页式开篇 */
.document-hero {
  padding: 128px 24px 100px;
  text-align: center;
}

.document-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  margin: 0 0 26px;
  color: var(--accent-ink);
  font-size: 15px;
  font-weight: 640;
  letter-spacing: 0.01em;
}

.document-eyebrow::before,
.document-eyebrow::after {
  content: "";
  width: 22px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  opacity: 0.5;
}

.document-hero h1 {
  max-width: 860px;
  margin: 0 auto;
  font-size: clamp(44px, 6vw, 72px);
  font-weight: 750;
  line-height: 1.08;
  letter-spacing: -0.04em;
}

.document-lead {
  max-width: 640px;
  margin: 26px auto 0;
  color: var(--ink-2);
  font-size: clamp(18px, 2vw, 21px);
  line-height: 1.66;
  letter-spacing: -0.012em;
}

.document-updated {
  margin: 28px 0 0;
  color: var(--ink-3);
  font-size: 13px;
}

/* 全宽章节带 — 内容用内边距收进阅读列 */
.document-body section,
.document-body > nav.topics {
  --col: 780px;
  padding: 88px max(24px, calc((100% - var(--col)) / 2));
  border-top: 1px solid var(--hairline);
  scroll-margin-top: 84px;
}

.document-body section:nth-of-type(even) {
  background: var(--surface);
}

.document-body > nav.topics {
  padding-bottom: 72px;
}

.document-body h2 {
  margin: 0 0 22px;
  font-size: clamp(28px, 3vw, 36px);
  font-weight: 720;
  line-height: 1.2;
  letter-spacing: -0.03em;
}

.document-body p,
.document-body ol,
.mcp-prose p,
.mcp-prose ol {
  margin: 0;
  color: var(--ink-2);
}

.document-body p + p,
.document-body p + ol,
.document-body ol + p,
.mcp-prose p + p,
.mcp-prose p + ol,
.mcp-prose ol + p {
  margin-top: 14px;
}

.document-body pre + p,
.document-body pre + ol,
.mcp-prose pre + p,
.mcp-prose pre + ol {
  margin-top: 18px;
}

.document-body ol,
.mcp-prose ol {
  padding-left: 1.4em;
}

.document-body li + li,
.mcp-prose ol li + li {
  margin-top: 10px;
}

.document-body a,
.mcp-prose a {
  color: var(--accent-ink);
  text-decoration: underline;
  text-decoration-color: rgba(0, 102, 204, 0.28);
  text-underline-offset: 3px;
}

.document-body a:hover,
.mcp-prose a:hover {
  text-decoration-color: currentColor;
}

.document-body code,
.mcp-prose code {
  color: var(--accent-ink);
  background: var(--accent-soft);
  padding: 2px 7px;
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 0.86em;
}

/* 终端窗口 */
.code-block {
  position: relative;
  overflow-x: auto;
  margin: 18px 0 0;
  padding: 48px 20px 18px;
  color: #cfe0f5;
  background: #0c1220;
  border: 1px solid #22304a;
  border-radius: 14px;
  box-shadow: 0 16px 40px rgba(12, 18, 32, 0.22);
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.8;
  white-space: pre;
  tab-size: 4;
}

.code-block::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 33px;
  border-bottom: 1px solid #1b2740;
  background:
    radial-gradient(circle at 19px 16.5px, #ff5f57 0 4.5px, transparent 5px),
    radial-gradient(circle at 38px 16.5px, #febc2e 0 4.5px, transparent 5px),
    radial-gradient(circle at 57px 16.5px, #28c840 0 4.5px, transparent 5px),
    linear-gradient(rgba(255, 255, 255, 0.03), rgba(255, 255, 255, 0));
}

.code-block .c-prompt {
  color: #5f739a;
  user-select: none;
}

.code-block .c-cm {
  color: #556586;
}

.document-body .code-block code,
.mcp-prose .code-block code,
.mcp-hero .code-block code,
.adv-card .code-block code {
  padding: 0;
  color: inherit;
  background: none;
  font-size: inherit;
}

/* 文档表格 */
.document-body table,
.mcp-prose table {
  width: 100%;
  margin: 10px 0 6px;
  border-collapse: collapse;
  font-size: 14px;
}

.document-body th,
.mcp-prose th {
  padding: 10px 14px 10px 0;
  color: var(--ink-3);
  border-bottom: 1px solid var(--hairline-strong);
  font-size: 12px;
  font-weight: 640;
  text-align: left;
  letter-spacing: 0.03em;
}

.document-body td,
.mcp-prose td {
  padding: 13px 14px 13px 0;
  color: var(--ink-2);
  border-bottom: 1px solid var(--hairline);
  vertical-align: top;
  line-height: 1.62;
}

.document-body tr:last-child td,
.mcp-prose tr:last-child td {
  border-bottom: 0;
}

.document-body td:first-child,
.mcp-prose td:first-child {
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 12.5px;
  white-space: nowrap;
}

/* MCP 页专属版式（hero 终端 / 原理流 / 示例卡 / 进阶卡 / 安全卡 / 收尾） */

/* MCP hero 终端 — 首屏主角 */
.mcp-hero {
  padding: 120px 24px 96px;
  text-align: center;
}

.mcp-prose {
  max-width: 780px;
}

.mcp-hero .code-block {
  width: min(660px, 100%);
  margin: 44px auto 0;
  text-align: left;
  font-size: 13.5px;
  box-shadow: 0 40px 90px rgba(12, 18, 32, 0.3), 0 8px 24px rgba(12, 18, 32, 0.18);
}

.mcp-hero-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 28px;
  margin: 30px 0 0;
  color: var(--ink-3);
  font-size: 13px;
}

.mcp-hero-meta a {
  color: var(--accent-ink);
}

/* 工作原理 — 三节点流（黑色叙事带内） */
.flow {
  display: grid;
  grid-template-columns: 1fr auto 1.15fr auto 1fr;
  align-items: stretch;
  gap: 14px;
  margin-top: 52px;
}

.flow-node {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 26px 24px;
  background: var(--band-card);
  border: 1px solid var(--band-card-border);
  border-radius: 18px;
  text-align: left;
}

.flow-node.core {
  background: linear-gradient(180deg, rgba(41, 151, 255, 0.14), rgba(41, 151, 255, 0.05));
  border-color: rgba(41, 151, 255, 0.32);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.35);
}

.flow-node small {
  color: var(--band-ink-2);
  font-size: 12px;
  letter-spacing: 0.04em;
}

.flow-node strong {
  color: var(--band-ink);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -0.014em;
}

.flow-node span {
  color: var(--band-ink-2);
  font-size: 13px;
  line-height: 1.5;
}

.flow-link {
  position: relative;
  align-self: center;
  width: clamp(36px, 6vw, 92px);
  padding: 26px 0;
}

.flow-link::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 0;
  right: 0;
  height: 1.5px;
  background: linear-gradient(90deg, transparent, var(--band-hairline) 18%, var(--band-hairline) 82%, transparent);
}

.flow-link::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 8%;
  width: 7px;
  height: 7px;
  margin-top: -3.5px;
  border-radius: 50%;
  background: var(--band-accent);
  box-shadow: 0 0 12px rgba(41, 151, 255, 0.8);
}

.flow-link small {
  position: absolute;
  top: calc(50% + 14px);
  left: 50%;
  transform: translateX(-50%);
  color: var(--band-ink-2);
  font-family: var(--font-mono);
  font-size: 10.5px;
  white-space: nowrap;
}

@media (prefers-reduced-motion: no-preference) {
  .flow-link::after {
    animation: flow-dot 3.2s var(--ease-out) infinite;
  }
}

@keyframes flow-dot {
  0% { left: 8%; opacity: 0; }
  12% { opacity: 1; }
  88% { opacity: 1; }
  100% { left: 88%; opacity: 0; }
}

/* 说一句话 — 示例卡 */
.say-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 48px;
}

.say-card {
  display: flex;
  flex-direction: column;
  padding: 26px 24px 22px;
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 18px;
}

.say-prompt {
  margin: 0;
  color: var(--ink);
  font-size: 15.5px;
  font-weight: 590;
  line-height: 1.6;
  letter-spacing: -0.008em;
}

.say-tools {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin-top: auto;
  padding-top: 22px;
  padding-bottom: 2px;
}

.say-tools + .say-note {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--card-row-line);
}

.say-tools code {
  padding: 4px 10px;
  color: var(--accent-ink);
  background: var(--accent-soft);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 11.5px;
}

.say-note {
  color: var(--ink-3);
  font-size: 12.5px;
  line-height: 1.55;
  margin: 0;
}

/* 进阶用法 — 迷你卡 */
.adv-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 44px;
}

.adv-card {
  display: flex;
  flex-direction: column;
  padding: 24px 22px;
  background: var(--surface);
  border: 1px solid var(--card-border);
  border-radius: 18px;
}

.adv-card h3 {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 680;
  letter-spacing: -0.012em;
}

.adv-card > p {
  margin: 0;
  color: var(--ink-2);
  font-size: 13.5px;
  line-height: 1.6;
}

.adv-card .code-block {
  margin: auto 0 0;
  margin-top: 18px;
  padding-top: 40px;
  border-radius: 12px;
  font-size: 12px;
  box-shadow: none;
}

/* 安全边界 — 黑色带四卡 */
.safety-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-top: 48px;
}

.safety-card {
  padding: 24px 22px;
  background: var(--band-card);
  border: 1px solid var(--band-card-border);
  border-radius: 18px;
}

.safety-card h3 {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 0 0 10px;
  color: var(--band-ink);
  font-size: 15.5px;
  font-weight: 680;
  letter-spacing: -0.01em;
}

.safety-card h3::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #30d158;
  box-shadow: 0 0 10px rgba(48, 209, 88, 0.55);
}

.safety-card p {
  margin: 0;
  color: var(--band-ink-2);
  font-size: 13px;
  line-height: 1.62;
}

/* MCP 收尾 */
.mcp-final {
  padding: 110px 24px 120px;
  text-align: center;
}

.mcp-final h2 {
  margin: 0;
  font-size: clamp(32px, 4vw, 48px);
  font-weight: 740;
  line-height: 1.12;
  letter-spacing: -0.032em;
}

.mcp-final-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px 36px;
  margin-top: 30px;
}

/* 客户端胶囊 */
.client-list {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 8px;
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
}

.client-list li {
  display: inline-flex;
  align-items: center;
  padding: 8px 15px;
  background: var(--surface);
  border: 1px solid var(--card-border);
  border-radius: 999px;
  font-size: 13px;
  font-weight: 580;
  line-height: 1;
  white-space: nowrap;
  transition: transform 0.3s var(--ease-apple), border-color 0.3s ease,
    color 0.3s ease;
}

.client-list li:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.client-list li:active {
  transform: scale(0.96);
}

/* 支持页主题速览磁贴 */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.topic-tile {
  display: flex;
  flex-direction: column;
  gap: 7px;
  padding: 24px 24px 20px;
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 18px;
  text-decoration: none;
  transition: transform 0.45s var(--ease-apple), border-color 0.3s ease,
    box-shadow 0.45s var(--ease-apple);
}

.topic-tile:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  box-shadow: var(--card-shadow);
}

.topic-tile:active {
  transform: scale(0.98);
}

.topic-tile strong {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  color: var(--ink);
  font-size: 16px;
  font-weight: 660;
  letter-spacing: -0.01em;
}

.topic-tile small {
  color: var(--ink-3);
  font-size: 13px;
  line-height: 1.5;
}

.topic-arrow {
  color: var(--accent-ink);
  font-weight: 640;
  transition: transform 0.3s var(--ease-apple);
}

.topic-tile:hover .topic-arrow {
  transform: translateX(4px);
}

/* ---------------------------------------------------------------
   17. 动效系统（零 JS）
   --------------------------------------------------------------- */

/* 17.1 首屏入场 — 时间驱动，错落上行 */
@media (prefers-reduced-motion: no-preference) {
  [data-load] {
    animation: load-rise 1.05s var(--ease-apple) both;
    animation-delay: var(--d, 0ms);
  }
}

@keyframes load-rise {
  from {
    opacity: 0;
    translate: 0 30px;
  }
}

/* 17.2 应用图标 — 轻盈悬浮 */
@media (prefers-reduced-motion: no-preference) {
  .hero-icon {
    animation: load-rise 1.05s var(--ease-apple) both, float 7s ease-in-out 1.4s infinite;
  }
}

@keyframes float {
  0%,
  100% {
    translate: 0 0;
  }
  50% {
    translate: 0 -11px;
  }
}

/* 17.3 滚动显现 — CSS 滚动时间线（Chrome 115+ / Safari 26+）。
   不支持的浏览器直接呈现最终状态，无任何降级闪烁。 */
@supports (animation-timeline: view()) {
  @media (prefers-reduced-motion: no-preference) {
    [data-reveal] {
      animation: reveal-rise both;
      animation-timeline: view();
      animation-range: entry 4% entry 52%;
    }

    [data-reveal="fade"] {
      animation-name: reveal-fade;
    }

    [data-reveal="left"] {
      animation-name: reveal-left;
    }

    [data-reveal="scale"] {
      animation-name: reveal-scale;
    }

    /* 子元素依次错落 */
    [data-reveal-stagger] > * {
      animation: reveal-rise both;
      animation-timeline: view();
      animation-range: entry 4% entry 52%;
    }

    [data-reveal-stagger] > *:nth-child(2) {
      animation-range: entry 8% entry 58%;
    }

    [data-reveal-stagger] > *:nth-child(3) {
      animation-range: entry 12% entry 64%;
    }

    [data-reveal-stagger] > *:nth-child(4) {
      animation-range: entry 16% entry 70%;
    }

    [data-reveal-stagger] > *:nth-child(n + 5) {
      animation-range: entry 20% entry 76%;
    }

    /* 传输进度 — 章节滚入时生长 */
    .transfer-card .transfer-bar i {
      transform: scaleX(0.06);
      animation: bar-grow both;
      animation-timeline: view();
      animation-range: entry 24% cover 42%;
    }

    /* MCP 对话 — 逐条落位 */
    .mcp-card .mcp-bubble,
    .mcp-card .mcp-tools {
      animation: reveal-rise both;
      animation-timeline: view();
    }

    .mcp-card .mcp-bubble.user {
      animation-range: entry 4% entry 46%;
    }

    .mcp-card .mcp-tools {
      animation-range: entry 12% entry 58%;
    }

    .mcp-card .mcp-bubble.ai {
      animation-range: entry 20% entry 70%;
    }
  }
}

@keyframes reveal-rise {
  from {
    opacity: 0;
    translate: 0 34px;
  }
}

@keyframes reveal-fade {
  from {
    opacity: 0;
  }
}

@keyframes reveal-left {
  from {
    opacity: 0;
    translate: -30px 0;
  }
}

@keyframes reveal-scale {
  from {
    opacity: 0;
    scale: 0.94;
  }
}

@keyframes bar-grow {
  to {
    transform: scaleX(0.68);
  }
}

/* ---------------------------------------------------------------
   18. 响应式
   --------------------------------------------------------------- */

@media (max-width: 1060px) {
  .security-grid {
    grid-template-columns: 1fr 1fr;
  }

  .say-grid,
  .adv-grid {
    grid-template-columns: 1fr;
  }

  .safety-grid {
    grid-template-columns: 1fr 1fr;
  }

  .flow {
    grid-template-columns: 1fr;
  }

  .flow-link {
    width: auto;
    height: 44px;
    padding: 0;
    justify-self: center;
  }

  .flow-link::before {
    top: 0;
    bottom: 0;
    left: 50%;
    right: auto;
    width: 1.5px;
    height: auto;
    background: linear-gradient(180deg, transparent, var(--band-hairline) 18%, var(--band-hairline) 82%, transparent);
  }

  .flow-link small {
    top: 50%;
    left: calc(50% + 16px);
    transform: translateY(-50%);
  }

  .flow-link::after {
    left: 50%;
    top: 8%;
    margin-top: 0;
    margin-left: -3.5px;
  }
}

@media (max-width: 1060px) and (prefers-reduced-motion: no-preference) {
  .flow-link::after {
    animation-name: flow-dot-v;
  }
}

@keyframes flow-dot-v {
  0% { top: 8%; opacity: 0; }
  12% { opacity: 1; }
  88% { opacity: 1; }
  100% { top: 88%; opacity: 0; }
}

@media (max-width: 980px) {
  .main-nav {
    display: none;
  }

  .header-inner {
    grid-template-columns: 1fr auto;
  }

  .mcp-hero {
    padding: 88px 20px 64px;
  }

  .section {
    padding: 96px 0;
  }

  .hero {
    padding-top: 76px;
  }

  .hero-shot {
    margin-top: 56px;
  }

  .chapter-body,
  .start-layout,
  .faq-layout {
    grid-template-columns: 1fr;
    gap: 52px;
  }

  .chapter-body {
    margin-top: 44px;
  }

  .chapter-body.flip .chapter-copy {
    order: 0;
  }

  .on-dark .btn-primary {
    color: #fff;
  }
}

@media (max-width: 700px) {
  body {
    font-size: 16px;
  }

  .inner,
  .header-inner {
    width: min(100% - 36px, 1200px);
  }

  .header-inner {
    min-height: 52px;
  }

  .header-download {
    padding-inline: 16px;
    font-size: 13px;
  }

  .section {
    padding: 84px 0;
  }

  .hero {
    padding-top: 64px;
  }

  .hero-icon {
    width: 88px;
    height: 88px;
    border-radius: 22px;
  }

  .hero h1 {
    font-size: clamp(42px, 12vw, 52px);
  }

  .hero-lead {
    margin-top: 22px;
    font-size: 17.5px;
  }

  .btn {
    width: 100%;
    max-width: 360px;
  }

  .hero-shot {
    width: calc(100% - 28px);
    margin-top: 44px;
  }

  .hero-shot-frame {
    border-radius: 14px;
  }

  .security-grid {
    grid-template-columns: 1fr;
    margin-top: 48px;
  }

  .security-grid article {
    padding: 26px 4px 28px;
  }

  .security-grid h3 {
    margin-top: 30px;
  }

  .undo-card {
    padding: 32px 22px 88px;
  }

  .undo-scene {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .move-origin {
    flex-direction: row;
    justify-content: flex-start;
    text-align: left;
    min-height: 96px;
  }

  .move-track {
    width: 1.5px;
    height: 30px;
    justify-self: center;
    background: linear-gradient(180deg, transparent, var(--ink-3) 22%, var(--ink-3) 78%, transparent);
  }

  .move-track span {
    font-size: 0;
  }

  .transfer-row {
    grid-template-columns: 36px 1fr;
  }

  .transfer-row .transfer-bar {
    grid-column: 2;
  }

  .object-row {
    grid-template-columns: 24px 1fr;
  }

  .object-row small {
    display: none;
  }

  .object-row.selected small {
    display: none;
  }

  .faq-layout {
    gap: 36px;
  }

  .faq-list summary {
    min-height: 80px;
    font-size: 15.5px;
  }

  .faq-list details p {
    margin-right: 0;
  }

  .final {
    padding: 110px 0 104px;
  }

  .final-icon {
    width: 92px;
    height: 92px;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    justify-items: start;
    gap: 14px;
  }

  .site-footer nav {
    justify-self: start;
  }

  .document-hero {
    padding: 88px 20px 64px;
  }

  .document-body section,
  .document-body > nav.topics {
    padding: 64px 20px;
  }

  .document-body h2 {
    font-size: 25px;
  }

  .topic-grid {
    grid-template-columns: 1fr;
  }

  .safety-grid {
    grid-template-columns: 1fr;
  }

  .mcp-hero .code-block {
    font-size: 12px;
  }

  .mcp-final {
    padding: 80px 20px 88px;
  }

  .document-body td:first-child,
  .mcp-prose td:first-child {
    white-space: normal;
  }

  .code-block {
    padding: 44px 14px 14px;
    font-size: 12px;
  }
}

/* ---------------------------------------------------------------
   19. 无障碍 — 减弱动态 / 减弱透明度 / 高对比度
   --------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }

  [data-reveal],
  [data-reveal-stagger] > *,
  .transfer-card .transfer-bar i,
  .mcp-card .mcp-bubble,
  .mcp-card .mcp-tools {
    opacity: 1 !important;
    translate: none !important;
    scale: none !important;
    transform: none !important;
    animation: none !important;
  }

  .transfer-card .transfer-bar i {
    transform: scaleX(0.68) !important;
  }
}

@media (prefers-reduced-transparency: reduce) {
  .site-header {
    background: var(--bg);
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
  }

  .on-dark .visual-card {
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
    background: #101013;
  }
}

@media (prefers-contrast: more) {
  :root {
    --hairline: rgba(0, 0, 0, 0.28);
    --card-border: rgba(0, 0, 0, 0.28);
  }

  .faq-list summary:hover {
    color: var(--ink);
  }
}