:root {
  --bg: #FAFAF8;
  --surface: #FFFFFF;
  --bg-alt: #F2F4F1;
  --text: #1E2628;
  --body: #5B6467;
  --muted: #879093;
  --blue: #46616C;
  --blue-dark: #354F59;
  --green: #5D7167;
  --green-dark: #485B52;
  --warm: #AD8059;
  --terracotta: #B46E50;
  --blue-light: #EDF2F3;
  --green-light: #EEF2EF;
  --warm-light: #F6EEE6;
  --border: #DDE2DE;
  --seam: #C7D0CC;
  --footer-bg: #EEF1EE;
  --footer-text: #4B5558;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --max-w: 1200px;
  --article-w: 800px;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg);
  color: var(--body);
  font-size: 16px;
  line-height: 1.8;
  font-weight: 400;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

main {
  flex: 1;
}

h1, h2, h3, h4 {
  color: var(--text);
  font-weight: 600;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

h1 {
  font-size: clamp(28px, 3.6vw, 48px);
  font-weight: 700;
}

h2 {
  font-size: clamp(22px, 2.5vw, 32px);
}

h3 {
  font-size: clamp(18px, 1.8vw, 22px);
}

p {
  margin-bottom: 1rem;
}

p:last-child {
  margin-bottom: 0;
}

a {
  color: var(--blue);
  text-decoration: none;
  transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease;
}

a:hover {
  color: var(--blue-dark);
}

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
  border-radius: 2px;
}

ul, ol {
  padding-left: 1.25rem;
}

.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* ==================================================
   Header (66px - 72px, #FFFFFF, 1px #DDE2DE)
   ================================================== */
.site-header {
  background-color: var(--surface);
  border-bottom: 1px solid var(--border);
  height: 70px;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--text);
  flex-shrink: 0;
}

.brand-logo {
  width: 38px;
  height: 32px;
  flex-shrink: 0;
  display: block;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand-name {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: 0.01em;
}

.brand-sub {
  font-size: 12px;
  color: var(--muted);
  margin-top: 2px;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 18px;
}

.main-nav a {
  font-size: 14px;
  color: var(--body);
  padding: 6px 2px;
  position: relative;
  white-space: nowrap;
  font-weight: 500;
}

.main-nav a:hover,
.main-nav a.active {
  color: var(--text);
}

.main-nav a.active::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background-color: var(--blue);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  background-color: var(--blue);
  color: #FFFFFF;
  font-size: 14px;
  font-weight: 600;
  padding: 9px 18px;
  border-radius: 4px;
  border: 1px solid var(--blue);
  white-space: nowrap;
}

.btn-primary:hover {
  background-color: var(--blue-dark);
  border-color: var(--blue-dark);
  color: #FFFFFF;
}

.btn-primary .arrow,
.btn-secondary .arrow,
.seam-link .arrow {
  display: inline-block;
  transition: transform 0.18s ease;
}

.btn-primary:hover .arrow,
.btn-secondary:hover .arrow,
.seam-link:hover .arrow {
  transform: translateX(3px);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  background-color: var(--surface);
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  padding: 9px 18px;
  border-radius: 4px;
  border: 1px solid var(--border);
  white-space: nowrap;
}

.btn-secondary:hover {
  background-color: var(--bg-alt);
  border-color: var(--seam);
  color: var(--text);
}

.btn-text {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: var(--blue);
  font-size: 14px;
  font-weight: 600;
  padding: 8px 6px;
}

.btn-text:hover {
  color: var(--blue-dark);
}

.mobile-menu-btn {
  display: none;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  padding: 7px 14px;
  border-radius: 4px;
  cursor: pointer;
  font-family: inherit;
}

.mobile-nav-panel {
  display: none;
  background-color: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 16px 24px 20px;
}

.mobile-nav-panel.is-open {
  display: block;
}

.mobile-nav-list {
  list-style: none;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px 16px;
  margin-bottom: 16px;
}

.mobile-nav-list a {
  display: block;
  padding: 8px 10px;
  background-color: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-size: 14px;
  font-weight: 500;
}

.mobile-nav-cta {
  display: flex;
}

.mobile-nav-cta .btn-primary {
  width: 100%;
}

/* ==================================================
   Hero Section ("双向对接面" - Desktop 680px-780px)
   ================================================== */
.hero-section {
  padding: 28px 0 36px;
  background-color: var(--bg);
  border-bottom: 1px solid var(--border);
}

.hero-frame {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  box-shadow: 0 10px 30px rgba(30, 38, 40, 0.025);
  min-height: 690px;
  max-height: 775px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  overflow: hidden;
}

.hero-brand-zone {
  text-align: center;
  padding: 24px 24px 18px;
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, var(--surface) 0%, var(--bg) 100%);
  position: relative;
  z-index: 2;
}

.hero-meta-bar {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  color: var(--muted);
  background-color: var(--surface);
  border: 1px solid var(--border);
  padding: 3px 12px;
  border-radius: 3px;
  margin-bottom: 8px;
}

.hero-meta-brand {
  color: var(--text);
  font-weight: 600;
}

.hero-slogan {
  font-size: 15px;
  color: var(--green-dark);
  font-weight: 600;
  letter-spacing: 0.06em;
  margin-bottom: 6px;
}

.hero-brand-zone h1 {
  font-size: clamp(24px, 2.7vw, 36px);
  max-width: 780px;
  margin: 0 auto 8px;
  color: var(--text);
}

.hero-desc {
  max-width: 740px;
  margin: 0 auto 14px;
  font-size: 15px;
  line-height: 1.65;
  color: var(--body);
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
}

/* Hero Docking Surface */
.hero-dock-header {
  display: grid;
  grid-template-columns: 1fr 96px 1fr;
  background-color: var(--bg-alt);
  border-bottom: 1px solid var(--border);
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  letter-spacing: 0.05em;
}

.hero-dock-col-left {
  padding: 8px 24px;
  text-align: right;
}

.hero-dock-col-mid {
  padding: 8px 0;
  text-align: center;
  border-left: 1px solid var(--border);
  border-right: 1px solid var(--border);
  color: var(--blue);
}

.hero-dock-col-right {
  padding: 8px 24px;
  text-align: left;
}

.hero-dock-matrix {
  display: flex;
  flex-direction: column;
  flex: 1;
  justify-content: stretch;
}

.hero-dock-row {
  display: grid;
  grid-template-columns: 1fr 96px 1fr;
  align-items: center;
  border-bottom: 1px solid var(--border);
  flex: 1;
  min-height: 72px;
  background-color: var(--surface);
  transition: background-color 0.18s ease;
}

.hero-dock-row:last-child {
  border-bottom: none;
}

.hero-dock-row:hover {
  background-color: var(--bg);
}

.hero-demand-cell {
  padding: 10px 24px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 14px;
  text-align: right;
}

.hero-demand-info {
  display: flex;
  flex-direction: column;
}

.hero-demand-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.3;
}

.hero-demand-sub {
  font-size: 13px;
  color: var(--muted);
  margin-top: 2px;
}

.dock-index {
  font-size: 13px;
  font-weight: 600;
  color: var(--warm);
  background-color: var(--warm-light);
  border: 1px solid #E8D9C8;
  padding: 2px 7px;
  border-radius: 3px;
  line-height: 1.3;
  flex-shrink: 0;
}

/* Central Seam ("中央接口缝") */
.hero-seam-cell {
  position: relative;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Vertical 2px central seam line */
.hero-seam-cell::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 2px;
  transform: translateX(-50%);
  background-color: var(--seam);
}

/* Horizontal interface tick mark */
.seam-joint {
  position: relative;
  z-index: 1;
  width: 44px;
  height: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: width 0.18s ease;
}

.seam-joint::before,
.seam-joint::after {
  content: "";
  height: 2px;
  width: 16px;
  background-color: var(--blue);
  transition: width 0.18s ease;
}

.seam-node {
  width: 8px;
  height: 8px;
  background-color: var(--surface);
  border: 2px solid var(--blue);
  flex-shrink: 0;
}

.hero-dock-row:hover .seam-joint {
  width: 52px;
}

.hero-dock-row:hover .seam-joint::before,
.hero-dock-row:hover .seam-joint::after {
  width: 20px;
}

.hero-solution-cell {
  padding: 10px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  text-align: left;
  transition: transform 0.18s ease;
}

.hero-dock-row:hover .hero-solution-cell {
  transform: translateX(2px);
}

.hero-solution-info {
  display: flex;
  flex-direction: column;
}

.hero-solution-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--blue-dark);
  line-height: 1.3;
}

.hero-solution-sub {
  font-size: 13px;
  color: var(--body);
  margin-top: 2px;
}

.mobile-match-label {
  display: none;
  font-size: 12px;
  color: var(--green-dark);
  font-weight: 600;
  margin-bottom: 2px;
}

.seam-link {
  font-size: 13px;
  font-weight: 600;
  color: var(--blue);
  background-color: var(--blue-light);
  padding: 5px 12px;
  border-radius: 3px;
  border: 1px solid #D5E0E3;
  white-space: nowrap;
  flex-shrink: 0;
}

.seam-link:hover {
  background-color: var(--blue);
  color: #FFFFFF;
  border-color: var(--blue);
}

/* ==================================================
   Section Shared Layout & Interface Docking System
   ================================================== */
.section-block {
  padding: 64px 0;
  border-bottom: 1px solid var(--border);
}

.section-block.bg-alt {
  background-color: var(--bg-alt);
}

.section-block.bg-surface {
  background-color: var(--surface);
}

.section-header {
  max-width: 820px;
  margin-bottom: 36px;
}

.section-index {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--warm);
  background-color: var(--warm-light);
  border: 1px solid #E6D7C6;
  padding: 2px 10px;
  border-radius: 3px;
  margin-bottom: 10px;
}

.section-header h2 {
  margin-bottom: 12px;
}

.section-lead {
  font-size: 16px;
  color: var(--body);
  line-height: 1.8;
}

.section-notice {
  margin-top: 12px;
  font-size: 13px;
  color: var(--muted);
  background-color: var(--surface);
  border-left: 3px solid var(--warm);
  padding: 8px 14px;
  border-top: 1px solid var(--border);
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

/* Generic Dual-Side Docking Board ("左需求 │ 中接口缝 │ 右方案") */
.dock-board {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}

.dock-board-head {
  display: grid;
  grid-template-columns: 36% 64px 1fr;
  background-color: var(--bg-alt);
  border-bottom: 1px solid var(--border);
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
}

.dock-board-head > div {
  padding: 12px 24px;
}

.dock-board-head .head-left {
  text-align: right;
}

.dock-board-head .head-seam {
  padding: 12px 0;
  text-align: center;
  border-left: 1px solid var(--border);
  border-right: 1px solid var(--border);
  color: var(--blue);
}

.dock-row {
  display: grid;
  grid-template-columns: 36% 64px 1fr;
  border-bottom: 1px solid var(--border);
  align-items: stretch;
  background-color: var(--surface);
  transition: background-color 0.18s ease;
}

.dock-row:last-child {
  border-bottom: none;
}

.dock-row:hover {
  background-color: #FCFDFB;
}

.dock-left {
  padding: 24px;
  text-align: right;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-end;
}

.dock-left-tag {
  font-size: 12px;
  font-weight: 600;
  color: var(--green-dark);
  background-color: var(--green-light);
  padding: 2px 8px;
  border-radius: 3px;
  margin-bottom: 6px;
}

.dock-left-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}

.dock-left-desc {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.6;
}

.dock-seam {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Central 1px interface line */
.dock-seam::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  transform: translateX(-50%);
  background-color: var(--seam);
}

.dock-tick {
  position: relative;
  z-index: 1;
  width: 34px;
  height: 2px;
  background-color: var(--seam);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: width 0.18s ease, background-color 0.18s ease;
}

.dock-tick::after {
  content: "";
  width: 7px;
  height: 7px;
  background-color: var(--surface);
  border: 1.5px solid var(--blue);
}

.dock-row:hover .dock-tick {
  width: 42px;
  background-color: var(--blue);
}

.dock-right {
  padding: 24px 28px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  transition: transform 0.18s ease;
}

.dock-row:hover .dock-right {
  transform: translateX(2px);
}

/* ==================================================
   Pricing Docking Row Specifics (#60 - #67, #113 - #126)
   ================================================== */
.plan-right-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.plan-main-meta {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.plan-title-line {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.plan-name {
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
}

.badge-recommend {
  display: inline-block;
  background-color: var(--terracotta);
  color: #FFFFFF;
  font-size: 12px;
  font-weight: 600;
  padding: 2px 9px;
  border-radius: 3px;
}

.plan-specs {
  display: flex;
  align-items: baseline;
  gap: 14px;
  flex-wrap: wrap;
}

.plan-price {
  font-size: 32px;
  font-weight: 700;
  color: var(--blue-dark);
  line-height: 1.2;
}

.plan-price small {
  font-size: 14px;
  font-weight: 500;
  color: var(--body);
}

.plan-quota {
  font-size: 16px;
  font-weight: 600;
  color: var(--green-dark);
  background-color: var(--surface);
  border: 1px solid var(--border);
  padding: 2px 10px;
  border-radius: 3px;
}

.plan-fit {
  font-size: 14px;
  color: var(--body);
  margin-top: 4px;
}

/* Featured Main Plan (#65, #123) */
.dock-row.is-featured {
  background-color: #FAFBF9;
}

.dock-row.is-featured .dock-seam::before {
  width: 3px;
  background-color: var(--green);
}

.dock-row.is-featured .dock-tick {
  background-color: var(--green);
  height: 3px;
}

.dock-row.is-featured .dock-right {
  background-color: var(--green-light);
  border-left: 3px solid var(--green);
  padding-left: 32px;
  padding-right: 32px;
}

/* ==================================================
   Node / AI / Streaming / Device Right Content
   ================================================== */
.solution-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 8px;
}

.solution-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
}

.solution-desc {
  font-size: 15px;
  color: var(--body);
  margin-bottom: 12px;
}

.solution-meta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 10px;
  margin-bottom: 12px;
}

.meta-item {
  background-color: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 8px 12px;
  font-size: 13px;
}

.meta-label {
  display: block;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 2px;
}

.meta-val {
  color: var(--body);
}

.platform-split {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 14px;
  margin-bottom: 12px;
}

.platform-box {
  background-color: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 14px 16px;
}

.platform-box h4 {
  font-size: 16px;
  font-weight: 700;
  color: var(--blue-dark);
  margin-bottom: 6px;
}

.platform-list {
  list-style: none;
  padding: 0;
  font-size: 13px;
}

.platform-list li {
  margin-bottom: 4px;
  color: var(--body);
}

.platform-list li strong {
  color: var(--text);
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 10px;
}

.op-tag {
  font-size: 13px;
  color: var(--text);
  background-color: var(--bg);
  border: 1px solid var(--border);
  padding: 3px 10px;
  border-radius: 3px;
}

/* ==================================================
   HTML Table (#85 - #86, #273: Horizontal lines only)
   ================================================== */
.table-wrap {
  margin-top: 32px;
  background-color: var(--surface);
  border-top: 2px solid var(--blue);
  border-bottom: 1px solid var(--border);
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 15px;
}

.comparison-table th {
  color: var(--text);
  font-weight: 600;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  background-color: var(--bg-alt);
}

.comparison-table td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  color: var(--body);
  vertical-align: top;
}

.comparison-table tr:last-child td {
  border-bottom: none;
}

.comparison-table td strong {
  color: var(--text);
}

/* Extended Q&A Strip (#87) */
.qa-extension-grid {
  margin-top: 28px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 16px;
}

.qa-ext-item {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--blue);
  padding: 16px 20px;
  border-radius: 4px;
}

.qa-ext-item h3 {
  font-size: 17px;
  margin-bottom: 6px;
}

.qa-ext-item p {
  font-size: 14px;
  color: var(--body);
}

/* ==================================================
   Tutorials Problem ↔ Guide Docking (#135 - #147)
   ================================================== */
.category-nav-strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 24px;
  padding: 14px 18px;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
}

.category-nav-label {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  margin-right: 4px;
}

.category-pill {
  font-size: 14px;
  font-weight: 500;
  color: var(--blue-dark);
  background-color: var(--blue-light);
  border: 1px solid #D4DFE2;
  padding: 5px 14px;
  border-radius: 3px;
}

.category-pill:hover {
  background-color: var(--blue);
  color: #FFFFFF;
  border-color: var(--blue);
}

.tutorial-right-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.tutorial-right-card + .tutorial-right-card {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px dashed var(--border);
}

.tutorial-title-link {
  font-size: 18px;
  font-weight: 600;
  color: var(--text);
}

.tutorial-title-link:hover {
  color: var(--blue);
}

.tutorial-excerpt {
  font-size: 14px;
  color: var(--body);
}

.tutorial-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 4px;
  font-size: 13px;
  color: var(--muted);
}

/* ==================================================
   FAQ Section ("问题 ↔ 答案" #169 - #173)
   ================================================== */
.faq-dock-list {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}

.faq-dock-item {
  display: grid;
  grid-template-columns: 38% 56px 1fr;
  border-bottom: 1px solid var(--border);
  align-items: stretch;
}

.faq-dock-item:last-child {
  border-bottom: none;
}

.faq-left {
  padding: 18px 22px;
  display: flex;
  align-items: flex-start;
  justify-content: flex-end;
  gap: 12px;
  text-align: right;
  background-color: #FCFDFB;
}

.faq-num {
  font-size: 13px;
  font-weight: 600;
  color: var(--warm);
  background-color: var(--warm-light);
  padding: 1px 7px;
  border-radius: 3px;
  flex-shrink: 0;
  margin-top: 2px;
}

.faq-question {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.45;
}

.faq-seam {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.faq-seam::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  transform: translateX(-50%);
  background-color: var(--seam);
}

.faq-seam-tick {
  width: 24px;
  height: 1px;
  background-color: var(--seam);
  position: relative;
  z-index: 1;
}

.faq-right {
  padding: 18px 24px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.faq-summary-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.faq-summary-text {
  font-size: 15px;
  color: var(--text);
  font-weight: 500;
}

.faq-toggle-btn {
  background-color: var(--bg-alt);
  border: 1px solid var(--border);
  color: var(--blue-dark);
  width: 30px;
  height: 30px;
  border-radius: 3px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.18s ease, color 0.18s ease;
}

.faq-toggle-btn:hover {
  background-color: var(--blue);
  color: #FFFFFF;
  border-color: var(--blue);
}

.faq-detail {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px dashed var(--border);
  font-size: 14px;
  color: var(--body);
  line-height: 1.75;
}

/* Progressive enhancement: only collapse full detail when JS is active */
html.js-enabled .faq-dock-item:not(.is-open) .faq-detail {
  display: none;
}

/* ==================================================
   Article & Category Pages (#148 - #154, #174 - #184)
   ================================================== */
.breadcrumb-bar {
  background-color: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 10px 0;
  font-size: 13px;
  color: var(--muted);
}

.breadcrumb-list {
  list-style: none;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.breadcrumb-list a {
  color: var(--body);
}

.breadcrumb-list a:hover {
  color: var(--blue);
}

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, var(--article-w)) 230px;
  justify-content: space-between;
  gap: 36px;
  padding: 40px 0 64px;
  align-items: start;
}

.article-main {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 40px 44px;
  max-width: var(--article-w);
  width: 100%;
}

.article-meta-top {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  font-size: 13px;
  color: var(--muted);
}

.article-cat-badge {
  background-color: var(--blue-light);
  color: var(--blue-dark);
  font-weight: 600;
  padding: 2px 10px;
  border-radius: 3px;
}

.article-main h1 {
  font-size: clamp(26px, 3vw, 36px);
  margin-bottom: 16px;
}

.article-abstract {
  font-size: 16px;
  color: var(--body);
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 24px;
}

/* Quick Conclusion Small Docking Box (#176 - #177) */
.quick-conclusion-dock {
  display: grid;
  grid-template-columns: 220px 36px 1fr;
  background-color: var(--bg);
  border: 1px solid var(--border);
  border-left: 3px solid var(--blue);
  border-radius: 4px;
  margin-bottom: 32px;
  align-items: stretch;
}

.qc-left {
  padding: 18px;
  text-align: right;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.qc-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--warm);
  margin-bottom: 4px;
}

.qc-question {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
}

.qc-seam {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.qc-seam::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  background-color: var(--seam);
}

.qc-seam::after {
  content: "";
  width: 18px;
  height: 2px;
  background-color: var(--blue);
  position: relative;
  z-index: 1;
}

.qc-right {
  padding: 18px 20px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.qc-right-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--blue-dark);
  margin-bottom: 4px;
}

.qc-right p {
  font-size: 15px;
  color: var(--text);
  line-height: 1.7;
}

/* Article Body Typography */
.article-content h2 {
  font-size: 24px;
  margin: 36px 0 14px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}

.article-content h2:first-of-type {
  border-top: none;
  padding-top: 0;
}

.article-content h3 {
  font-size: 19px;
  margin: 24px 0 10px;
}

.article-content p {
  font-size: 16px;
  line-height: 1.85;
  color: var(--body);
  margin-bottom: 16px;
}

.article-content ul,
.article-content ol {
  margin-bottom: 18px;
  padding-left: 20px;
}

.article-content li {
  margin-bottom: 8px;
  line-height: 1.75;
}

.article-content li strong {
  color: var(--text);
}

.article-callout {
  background-color: var(--green-light);
  border-left: 3px solid var(--green);
  padding: 16px 20px;
  margin: 20px 0;
  border-radius: 3px;
}

.article-callout h4 {
  font-size: 15px;
  color: var(--green-dark);
  margin-bottom: 6px;
}

/* Desktop Sidebar TOC (220px-240px #181) */
.article-sidebar {
  width: 230px;
  position: sticky;
  top: 90px;
}

.toc-box {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 18px;
}

.toc-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  padding-bottom: 10px;
  margin-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.toc-list {
  list-style: none;
  padding: 0;
  max-height: calc(100vh - 220px);
  overflow-y: auto;
}

.toc-list li {
  margin-bottom: 8px;
  line-height: 1.4;
}

.toc-list a {
  font-size: 13px;
  color: var(--body);
  display: block;
}

.toc-list a:hover {
  color: var(--blue);
}

/* Mobile Collapsible TOC (#182) */
.mobile-toc {
  display: none;
  background-color: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 12px 16px;
  margin-bottom: 24px;
}

.mobile-toc summary {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  cursor: pointer;
}

.mobile-toc ul {
  margin-top: 10px;
  padding-left: 16px;
  font-size: 14px;
}

.mobile-toc li {
  margin-bottom: 6px;
}

/* Article Bottom Navigation & Related Links (#183, #199) */
.article-footer-box {
  margin-top: 40px;
  padding-top: 28px;
  border-top: 2px solid var(--border);
}

.related-reading-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
  margin-top: 14px;
  margin-bottom: 24px;
}

.related-item {
  background-color: var(--bg);
  border: 1px solid var(--border);
  padding: 14px 16px;
  border-radius: 4px;
}

.related-item span {
  display: block;
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 4px;
}

.related-item a {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
}

.related-item a:hover {
  color: var(--blue);
}

.article-pager {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  font-size: 14px;
}

/* ==================================================
   Category & Sitemap Stable Lists (#148 - #154)
   ================================================== */
.article-stream-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: 28px;
}

.stream-article-item {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 24px 28px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.stream-article-item h2,
.stream-article-item h3 {
  font-size: 20px;
}

.stream-article-item h2 a,
.stream-article-item h3 a {
  color: var(--text);
}

.stream-article-item h2 a:hover,
.stream-article-item h3 a:hover {
  color: var(--blue);
}

/* ==================================================
   Footer (#211 - #218, Desktop 250px-320px, #EEF1EE)
   ================================================== */
.site-footer {
  background-color: var(--footer-bg);
  color: var(--footer-text);
  border-top: 1px solid var(--border);
  padding: 36px 0 24px;
  font-size: 14px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr 1fr;
  gap: 0;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}

.footer-col {
  padding: 0 20px;
  border-left: 1px solid var(--border);
}

.footer-col:first-child {
  padding-left: 0;
  border-left: none;
}

.footer-col:last-child {
  padding-right: 0;
}

.footer-brand-desc {
  font-size: 13px;
  color: var(--body);
  margin: 10px 0 14px;
}

.footer-col-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
}

.footer-links {
  list-style: none;
  padding: 0;
}

.footer-links li {
  margin-bottom: 6px;
  line-height: 1.4;
}

.footer-links a {
  color: var(--footer-text);
  font-size: 13px;
}

.footer-links a:hover {
  color: var(--text);
}

.footer-bottom {
  padding-top: 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 13px;
  color: var(--body);
}

.friend-links {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
}

.friend-links a {
  color: var(--footer-text);
}

.friend-links a:hover {
  color: var(--blue-dark);
}

/* ==================================================
   Responsive Breakpoints (1024px, 768px, 430px, 375px)
   ================================================== */
@media (max-width: 1080px) {
  .main-nav {
    display: none;
  }
  .mobile-menu-btn {
    display: inline-flex;
  }
  .article-layout {
    grid-template-columns: 1fr;
  }
  .article-sidebar {
    display: none;
  }
  .mobile-toc {
    display: block;
  }
  .article-main {
    max-width: 100%;
    padding: 28px 24px;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }

  .header-inner {
    padding: 0 16px;
  }

  .header-actions .btn-primary {
    display: none;
  }

  /* Mobile Hero: Cancel Left-Right Docking -> Demand ↓ Answer (#49 - #50) */
  .hero-frame {
    min-height: auto;
    max-height: none;
  }

  .hero-brand-zone {
    padding: 22px 16px 18px;
    text-align: left;
  }

  .hero-cta-group {
    justify-content: flex-start;
  }

  .hero-dock-header {
    display: none;
  }

  .hero-dock-row {
    grid-template-columns: 1fr;
    padding: 14px 16px;
    gap: 8px;
  }

  .hero-demand-cell {
    padding: 0;
    justify-content: flex-start;
    text-align: left;
    flex-direction: row-reverse;
  }

  .hero-seam-cell {
    display: none;
  }

  .hero-solution-cell {
    padding: 10px 12px;
    background-color: var(--bg);
    border: 1px solid var(--border);
    border-left: 3px solid var(--blue);
    border-radius: 4px;
  }

  .mobile-match-label {
    display: block;
  }

  /* Mobile Docking Sections: Demand ↓ Solution (#67, #126, #232 - #238) */
  .section-block {
    padding: 44px 0;
  }

  .dock-board-head {
    display: none;
  }

  .dock-board {
    display: flex;
    flex-direction: column;
  }

  .dock-row {
    display: flex;
    flex-direction: column;
    padding: 18px 16px;
    gap: 12px;
  }

  .dock-left {
    padding: 0;
    text-align: left;
    align-items: flex-start;
  }

  .dock-seam {
    display: none;
  }

  .dock-right {
    padding: 14px 16px;
    background-color: var(--bg);
    border: 1px solid var(--border);
    border-top: 2px solid var(--seam);
    border-radius: 4px;
  }

  .dock-row.is-featured .dock-right {
    padding: 16px;
    border-left: 1px solid var(--green);
    border-top: 3px solid var(--green);
  }

  /* Mobile Plan Order: 主力 -> 日常 -> 轻量 -> 高频 -> 长期 (#67, #233) */
  .plan-dock-board .dock-row.plan-order-main {
    order: 1;
  }
  .plan-dock-board .dock-row.plan-order-daily {
    order: 2;
  }
  .plan-dock-board .dock-row.plan-order-light {
    order: 3;
  }
  .plan-dock-board .dock-row.plan-order-high {
    order: 4;
  }
  .plan-dock-board .dock-row.plan-order-long {
    order: 5;
  }

  /* Mobile Responsive Table (#273) */
  .comparison-table,
  .comparison-table thead,
  .comparison-table tbody,
  .comparison-table tr,
  .comparison-table td {
    display: block;
    width: 100%;
  }

  .comparison-table thead {
    display: none;
  }

  .comparison-table tr {
    padding: 14px 16px;
    border-bottom: 1px solid var(--border);
  }

  .comparison-table td {
    padding: 4px 0;
    border-bottom: none;
  }

  .comparison-table td::before {
    content: attr(data-label) "：";
    font-weight: 600;
    color: var(--text);
  }

  /* Mobile FAQ: Question ↓ Answer (#173) */
  .faq-dock-item {
    grid-template-columns: 1fr;
    padding: 16px;
    gap: 10px;
  }

  .faq-left {
    padding: 0;
    justify-content: flex-start;
    text-align: left;
    background-color: transparent;
  }

  .faq-seam {
    display: none;
  }

  .faq-right {
    padding: 12px 14px;
    background-color: var(--bg);
    border-radius: 4px;
    border: 1px solid var(--border);
  }

  /* Mobile Quick Conclusion (#177) */
  .quick-conclusion-dock {
    grid-template-columns: 1fr;
  }

  .qc-left {
    text-align: left;
    padding: 14px 16px 8px;
  }

  .qc-seam {
    display: none;
  }

  .qc-right {
    padding: 8px 16px 14px;
    border-top: 1px dashed var(--border);
  }

  /* Mobile Footer (#239) */
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .footer-col {
    padding: 0;
    border-left: none;
    border-bottom: 1px solid var(--border);
    padding-bottom: 16px;
  }

  .footer-col:last-child {
    border-bottom: none;
    padding-bottom: 0;
  }

  .footer-bottom {
    flex-direction: column-reverse;
    align-items: flex-start;
  }
}

@media (max-width: 430px) {
  .mobile-nav-list {
    grid-template-columns: 1fr;
  }
  .article-main {
    padding: 20px 16px;
  }
  .plan-price {
    font-size: 28px;
  }
}

/* ==================================================
   Reduced Motion (#230, #261)
   ================================================== */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .hero-dock-row:hover .hero-solution-cell,
  .dock-row:hover .dock-right,
  .btn-primary:hover .arrow,
  .btn-secondary:hover .arrow,
  .seam-link:hover .arrow {
    transform: none !important;
  }
}