/* ==========================================================================
   隐云机场 - 第3套设计系统：隐框画布系统 (Hidden Frame Canvas System)
   核心概念：大画布 + 1px隐框 + 框中框 + 嵌套信息区域 + 建筑感
   ========================================================================== */

:root {
  /* 主色板 */
  --bg-main: #FCFCF9;
  --bg-pure: #FFFFFF;
  --bg-alt: #F5F4EF;
  --bg-tint-blue: #EFF2F2;
  --bg-tint-green: #F0F2EF;

  /* 文字颜色 */
  --text-main: #1E2325;
  --text-body: #606669;
  --text-muted: #8A8F91;

  /* 墨蓝与灰绿 */
  --color-slate: #4D626B;
  --color-slate-dark: #3C4F57;
  --color-green: #627069;
  --color-green-dark: #4F5C56;

  /* 陶土与暖棕 (5%点缀) */
  --color-terracotta: #AA6C51;
  --color-warm-brown: #9D7960;

  /* 边框体系 (1px细线) */
  --border-light: #DDDDD7;
  --border-dark: #BCC4C2;
  --border-accent: #4D626B;

  /* 字体栈 */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  /* 容器最大宽度 */
  --canvas-max-width: 1280px;
  --article-max-width: 800px;
}

/* 全局重置与基础设定 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-main);
  font-size: 16px;
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  background-color: var(--bg-main);
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.15s ease, border-color 0.15s ease;
}

img, svg {
  vertical-align: middle;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

ul, ol {
  list-style: none;
}

/* 布局大画布容器 */
.canvas-wrapper {
  width: 100%;
  max-width: var(--canvas-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* 1px 隐框基础体系 */
.frame-box {
  position: relative;
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  border-radius: 0px;
  transition: border-color 0.2s ease;
}

.frame-box-transparent {
  position: relative;
  border: 1px solid var(--border-light);
  background-color: transparent;
  border-radius: 0px;
}

.frame-box-nested {
  border: 1px solid var(--border-light);
  background-color: var(--bg-main);
  position: relative;
}

/* 标题压线效果：标题嵌入在边框线上 */
.frame-title-online {
  position: absolute;
  top: -12px;
  left: 24px;
  background-color: var(--bg-main);
  padding: 0 10px;
  font-size: 13px;
  font-weight: 600;
  color: var(--color-slate);
  letter-spacing: 0.04em;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  z-index: 2;
  white-space: nowrap;
}

.frame-title-pure-bg {
  background-color: var(--bg-pure);
}

/* 不完全闭合角体系 */
.corner-open-tr {
  position: relative;
}
.corner-open-tr::before {
  content: "";
  position: absolute;
  top: -1px;
  right: 24px;
  width: 20px;
  height: 2px;
  background-color: var(--bg-main);
  z-index: 3;
}

.corner-open-bl {
  position: relative;
}
.corner-open-bl::before {
  content: "";
  position: absolute;
  bottom: -1px;
  left: 24px;
  width: 20px;
  height: 2px;
  background-color: var(--bg-main);
  z-index: 3;
}

/* 极简按钮与CTA */
.btn-cta-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 24px;
  font-size: 14px;
  font-weight: 600;
  color: #FFFFFF;
  background-color: var(--color-slate);
  border: 1px solid var(--color-slate-dark);
  border-radius: 0px;
  transition: background-color 0.15s ease, transform 0.15s ease;
  white-space: nowrap;
}

.btn-cta-primary:hover {
  background-color: var(--color-slate-dark);
  transform: translateY(-1px);
}

.btn-cta-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 24px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-main);
  background-color: transparent;
  border: 1px solid var(--border-light);
  border-radius: 0px;
  transition: border-color 0.15s ease, background-color 0.15s ease;
  white-space: nowrap;
}

.btn-cta-secondary:hover {
  border-color: var(--text-main);
  background-color: var(--bg-pure);
}

.btn-cta-inline {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--color-slate);
  transition: color 0.15s ease, gap 0.15s ease;
}

.btn-cta-inline:hover {
  color: var(--color-terracotta);
  gap: 9px;
}

/* 徽章与标签 */
.tag-badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.02em;
  border: 1px solid var(--border-light);
  background-color: var(--bg-alt);
  color: var(--color-slate);
}

.tag-badge-terracotta {
  background-color: #FBF4F1;
  border-color: #E6CEC4;
  color: var(--color-terracotta);
}

/* 顶部导航 Header */
.site-header {
  height: 70px;
  background-color: var(--bg-main);
  border-bottom: 1px solid var(--border-light);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-logo-svg {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
}

.brand-text-block {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--text-main);
  line-height: 1.2;
}

.brand-tagline {
  font-size: 11px;
  color: var(--text-muted);
  line-height: 1.3;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-link {
  font-size: 14px;
  color: var(--text-body);
  position: relative;
  padding: 6px 0;
  transition: color 0.15s ease;
}

.nav-link:hover {
  color: var(--text-main);
}

.nav-link.active {
  color: var(--color-slate);
  font-weight: 600;
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 1px;
  background-color: var(--color-slate);
}

.header-cta-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

.mobile-menu-btn {
  display: none;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  color: var(--text-main);
}

.mobile-menu-drawer {
  display: none;
  background-color: var(--bg-main);
  border-bottom: 1px solid var(--border-light);
  padding: 16px 24px 24px;
}

.mobile-nav-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.mobile-nav-link {
  font-size: 15px;
  color: var(--text-body);
  padding: 8px 0;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.mobile-nav-link.active {
  color: var(--color-slate);
  font-weight: 600;
}

/* ==========================================================================
   首页专属：隐框大画布 HERO 结构
   单一大外框 (620-720px 高度在 Desktop) + 内部嵌套信息框
   ========================================================================== */

.hero-section {
  padding-top: 40px;
  padding-bottom: 60px;
}

.hero-outer-canvas {
  padding: 48px;
  background-color: var(--bg-pure);
  border: 1px solid var(--border-light);
  min-height: 640px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
}

.hero-top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-light);
  margin-bottom: 36px;
}

.hero-meta-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--color-slate);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero-meta-brand {
  font-size: 13px;
  color: var(--text-muted);
}

.hero-main-content {
  margin-bottom: 40px;
}

.hero-lead-quote {
  font-size: 15px;
  color: var(--color-slate);
  margin-bottom: 12px;
  font-weight: 500;
  letter-spacing: 0.03em;
}

.hero-h1 {
  font-size: 44px;
  line-height: 1.25;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}

.hero-sub-categories {
  font-size: 15px;
  color: var(--color-green);
  font-weight: 500;
  margin-bottom: 18px;
}

.hero-desc {
  max-width: 820px;
  font-size: 16px;
  color: var(--text-body);
  line-height: 1.85;
  margin-bottom: 28px;
}

.hero-cta-bar {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* Hero 内部嵌套 4 大信息框：Desktop 采用 2 + 1 结构 */
.hero-nested-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  padding-top: 28px;
  border-top: 1px solid var(--border-light);
}

.hero-nested-box {
  padding: 24px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-main);
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 160px;
}

.hero-nested-box.full-width {
  grid-column: 1 / -1;
}

.hero-nested-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.hero-nested-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: 0.02em;
}

.hero-nested-body {
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.75;
  margin-bottom: 16px;
}

.hero-chips-wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.hero-chip {
  padding: 3px 10px;
  font-size: 12px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  color: var(--text-main);
}

/* ==========================================================================
   板块统一风格：段落大外框体系
   ========================================================================== */

.section-block {
  padding-top: 60px;
  padding-bottom: 60px;
}

.section-header-wrap {
  margin-bottom: 32px;
}

.section-index-num {
  font-size: 13px;
  font-weight: 700;
  color: var(--color-slate);
  letter-spacing: 0.06em;
  margin-bottom: 6px;
}

.section-h2 {
  font-size: 30px;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.35;
  letter-spacing: -0.01em;
}

.section-intro-text {
  font-size: 16px;
  color: var(--text-body);
  line-height: 1.85;
  margin-top: 12px;
  max-width: 860px;
}

/* 01 / 套餐选择框 (4个轻量子区域，非Card) */
.plan-select-canvas {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
}

.plan-sub-zone {
  padding: 32px 24px;
  border-right: 1px solid var(--border-light);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background-color: var(--bg-pure);
  position: relative;
}

.plan-sub-zone:last-child {
  border-right: none;
}

.plan-sub-zone.highlight {
  background-color: var(--bg-tint-green);
  border-top: 2px solid var(--color-green);
}

.plan-zone-badge-wrap {
  margin-bottom: 12px;
  min-height: 24px;
}

.plan-zone-traffic {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.2;
  margin-bottom: 4px;
}

.plan-zone-name {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 20px;
  font-weight: 500;
}

.plan-zone-fit-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--color-slate);
  margin-bottom: 8px;
}

.plan-zone-tags {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 24px;
  font-size: 13px;
  color: var(--text-body);
}

.plan-traffic-footnote {
  padding: 16px 24px;
  border-top: 1px solid var(--border-light);
  font-size: 13px;
  color: var(--text-muted);
  background-color: var(--bg-alt);
}

/* 02 / 节点地区 (大外框，内部 2x2 细线划分，非卡片) */
.node-outer-canvas {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.node-zone-cell {
  padding: 36px 32px;
  border-right: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 220px;
}

.node-zone-cell:nth-child(2n) {
  border-right: none;
}

.node-zone-cell:nth-child(3),
.node-zone-cell:nth-child(4) {
  border-bottom: none;
}

.node-cell-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

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

.node-cell-desc {
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 20px;
}

.node-factor-label {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.node-factor-text {
  font-size: 13px;
  color: var(--color-slate-dark);
  font-weight: 500;
  margin-bottom: 20px;
}

/* 03 / 线路知识 (左侧解释 + 右侧 HTML Table 快速比较 + 扩展问答) */
.lines-outer-canvas {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
}

.lines-top-split {
  display: grid;
  grid-template-columns: 360px 1fr;
  border-bottom: 1px solid var(--border-light);
}

.lines-left-explain {
  padding: 36px 32px;
  border-right: 1px solid var(--border-light);
  background-color: var(--bg-main);
}

.lines-table-wrap {
  padding: 36px 32px;
  overflow-x: auto;
}

.lines-compare-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 14px;
}

.lines-compare-table th {
  padding: 12px 16px;
  border-bottom: 1px solid var(--text-main);
  font-weight: 700;
  color: var(--text-main);
  background-color: transparent;
  white-space: nowrap;
}

.lines-compare-table td {
  padding: 16px 16px;
  border-bottom: 1px solid var(--border-light);
  color: var(--text-body);
  vertical-align: top;
}

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

.lines-deep-qa-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  padding: 32px;
  gap: 24px;
  background-color: var(--bg-pure);
}

.lines-qa-item {
  padding: 20px 24px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-main);
}

.lines-qa-question {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 10px;
}

.lines-qa-answer {
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.8;
}

/* 04 / AI与流媒体 (60% / 40% 分割) */
.ai-stream-canvas {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  display: grid;
  grid-template-columns: 6fr 4fr;
}

.ai-zone-col {
  padding: 36px 32px;
  border-right: 1px solid var(--border-light);
}

.stream-zone-col {
  padding: 36px 32px;
}

.ai-zone-header, .stream-zone-header {
  margin-bottom: 20px;
}

.zone-col-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 8px;
}

.zone-col-desc {
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.8;
}

.ai-two-col-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 24px;
}

.ai-item-row {
  padding: 16px 18px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-main);
}

.ai-item-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 6px;
}

.ai-item-factor {
  font-size: 13px;
  color: var(--text-body);
  line-height: 1.6;
  margin-bottom: 12px;
}

.stream-vertical-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-top: 24px;
}

.stream-item-row {
  padding: 14px 18px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-main);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.stream-item-info {
  display: flex;
  flex-direction: column;
}

.stream-item-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
}

.stream-item-factor {
  font-size: 12px;
  color: var(--text-muted);
}

/* 05 / 客户端 (4 分区：细线划分) */
.client-outer-canvas {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.client-quadrant {
  padding: 36px 32px;
  border-right: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.client-quadrant:nth-child(2n) {
  border-right: none;
}

.client-quadrant:nth-child(3),
.client-quadrant:nth-child(4) {
  border-bottom: none;
}

.client-platform-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.client-steps-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 24px;
}

.client-step-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 14px;
  color: var(--text-body);
}

.client-step-index {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-slate);
  padding-top: 2px;
  min-width: 16px;
}

/* ==========================================================================
   06 / 完整套餐：套中套价格框 (Nested In-Frame Pricing)
   主力方案占据最大面积 + 下方四条横向细栏
   ========================================================================== */

.pricing-outer-canvas {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  padding: 40px;
  position: relative;
}

.pricing-canvas-header {
  margin-bottom: 32px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
}

.pricing-canvas-title {
  font-size: 26px;
  font-weight: 700;
  color: var(--text-main);
}

.pricing-canvas-sub {
  font-size: 14px;
  color: var(--text-muted);
}

/* 主力方案嵌套大框 */
.primary-plan-nested-frame {
  background-color: var(--bg-tint-green);
  border: 1px solid var(--border-dark);
  border-top: 3px solid var(--color-green);
  padding: 36px 40px;
  margin-bottom: 32px;
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 32px;
  align-items: center;
  position: relative;
}

.primary-plan-badge-line {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}

.primary-plan-name {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-main);
}

.primary-plan-features {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
  margin-top: 16px;
  font-size: 14px;
  color: var(--color-green-dark);
}

.primary-plan-price-block {
  text-align: right;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  justify-content: center;
}

.plan-price-num {
  font-size: 38px;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1;
  letter-spacing: -0.02em;
}

.plan-price-period {
  font-size: 14px;
  color: var(--text-muted);
  margin-top: 4px;
  margin-bottom: 18px;
}

/* 其他四档横向细栏 */
.other-plans-list {
  display: flex;
  flex-direction: column;
  border-top: 1px solid var(--border-light);
}

.plan-row-item {
  display: grid;
  grid-template-columns: 180px 140px 140px 1fr 140px;
  align-items: center;
  padding: 20px 16px;
  border-bottom: 1px solid var(--border-light);
  transition: background-color 0.15s ease;
}

.plan-row-item:hover {
  background-color: var(--bg-alt);
}

.plan-row-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
}

.plan-row-traffic {
  font-size: 14px;
  color: var(--text-body);
  font-weight: 600;
}

.plan-row-price {
  font-size: 16px;
  font-weight: 700;
  color: var(--color-slate-dark);
}

.plan-row-usage {
  font-size: 13px;
  color: var(--text-muted);
}

.plan-row-action {
  text-align: right;
}

/* 快速选择指导条 */
.quick-selection-bar {
  margin-top: 24px;
  padding: 16px 20px;
  background-color: var(--bg-alt);
  border: 1px solid var(--border-light);
  display: flex;
  flex-wrap: wrap;
  gap: 16px 32px;
  font-size: 13px;
  color: var(--text-body);
}

.quick-selection-bar span strong {
  color: var(--text-main);
}

/* ==========================================================================
   07 / 隐云机场评测入口框
   ========================================================================== */

.review-preview-canvas {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  padding: 40px;
}

.review-preview-content {
  max-width: 860px;
}

.review-preview-h2 {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 16px;
}

.review-preview-desc {
  font-size: 15px;
  color: var(--text-body);
  line-height: 1.85;
  margin-bottom: 24px;
}

.review-preview-highlights {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 28px;
}

.review-highlight-box {
  padding: 16px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-main);
}

.review-highlight-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--color-slate);
  margin-bottom: 6px;
}

.review-highlight-desc {
  font-size: 13px;
  color: var(--text-muted);
}

/* ==========================================================================
   08 / 内容中心：大外框 + 嵌套子框 (非Card，非九宫格)
   ========================================================================== */

.content-hub-canvas {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
}

.content-hub-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  border-bottom: 1px solid var(--border-light);
}

.hub-sub-box {
  padding: 36px 32px;
  border-right: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.hub-sub-box:nth-child(2n) {
  border-right: none;
}

.hub-sub-box.full-width {
  grid-column: 1 / -1;
  border-right: none;
  border-bottom: none;
}

.hub-box-category-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.hub-article-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.hub-article-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.hub-article-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-main);
  line-height: 1.5;
  transition: color 0.15s ease;
}

.hub-article-title:hover {
  color: var(--color-slate);
}

.hub-article-meta {
  font-size: 12px;
  color: var(--text-muted);
  display: flex;
  gap: 12px;
}

/* ==========================================================================
   09 / 网络排障：问题嵌套框 (4个不同大小的排障大类)
   ========================================================================== */

.trouble-outer-canvas {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.trouble-box {
  padding: 32px;
  border-right: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.trouble-box.large {
  grid-column: 1 / 2;
  grid-row: 1 / 3;
  background-color: var(--bg-tint-blue);
}

.trouble-box.full-width {
  grid-column: 1 / -1;
  border-right: none;
  border-bottom: none;
}

.trouble-box:nth-child(3) {
  border-right: none;
}

.trouble-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 12px;
}

.trouble-desc {
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 18px;
}

.trouble-check-steps {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 13px;
  color: var(--text-body);
}

.trouble-step-point {
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.trouble-step-point::before {
  content: "—";
  color: var(--color-slate);
}

/* ==========================================================================
   10 / FAQ 常见问题 (大外框 + 1px 横线手风琴)
   ========================================================================== */

.faq-outer-canvas {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
}

.faq-item {
  border-bottom: 1px solid var(--border-light);
}

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

.faq-trigger {
  width: 100%;
  padding: 22px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  text-align: left;
  background: none;
  font-size: 16px;
  font-weight: 600;
  color: var(--text-main);
  transition: background-color 0.15s ease;
}

.faq-trigger:hover {
  background-color: var(--bg-alt);
}

.faq-q-number {
  font-size: 13px;
  font-weight: 700;
  color: var(--color-slate);
  margin-right: 14px;
  font-family: var(--font-mono);
}

.faq-icon-cross {
  font-size: 18px;
  font-weight: 400;
  color: var(--text-muted);
  transition: transform 0.2s ease;
  flex-shrink: 0;
  margin-left: 12px;
}

.faq-item.open .faq-icon-cross {
  transform: rotate(45deg);
  color: var(--color-slate);
}

.faq-answer-panel {
  padding: 0 28px 24px 56px;
  font-size: 15px;
  color: var(--text-body);
  line-height: 1.85;
  display: none;
}

.faq-item.open .faq-answer-panel {
  display: block;
}

/* ==========================================================================
   文章详情页排版 (建筑型阅读风，最大宽度 800px)
   ========================================================================== */

.article-page-layout {
  padding-top: 40px;
  padding-bottom: 80px;
}

.article-header-frame {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  padding: 40px;
  margin-bottom: 36px;
}

.article-breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 18px;
}

.article-breadcrumbs a:hover {
  color: var(--text-main);
}

.article-h1 {
  font-size: 36px;
  line-height: 1.35;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.01em;
  margin-bottom: 16px;
}

.article-summary-lead {
  font-size: 16px;
  color: var(--text-body);
  line-height: 1.85;
  margin-bottom: 24px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border-light);
}

.article-meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  font-size: 13px;
  color: var(--text-muted);
}

.article-body-container {
  display: grid;
  grid-template-columns: 1fr 240px;
  gap: 48px;
  align-items: start;
}

.article-content-main {
  max-width: var(--article-max-width);
  background-color: var(--bg-pure);
  border: 1px solid var(--border-light);
  padding: 48px 40px;
}

/* 快速结论细边框框 */
.quick-conclusion-frame {
  border: 1px solid var(--color-slate);
  background-color: var(--bg-tint-blue);
  padding: 24px;
  margin-bottom: 36px;
  position: relative;
}

.quick-conclusion-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-slate-dark);
  margin-bottom: 8px;
}

.quick-conclusion-text {
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.85;
}

/* 正文标题与段落样式 */
.article-content-main h2 {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-main);
  margin-top: 40px;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-light);
}

.article-content-main h3 {
  font-size: 19px;
  font-weight: 600;
  color: var(--text-main);
  margin-top: 28px;
  margin-bottom: 12px;
}

.article-content-main p {
  font-size: 16px;
  color: var(--text-body);
  line-height: 1.9;
  margin-bottom: 20px;
}

.article-content-main ul, .article-content-main ol {
  margin-bottom: 24px;
  padding-left: 20px;
}

.article-content-main ul li {
  list-style: square;
  font-size: 15px;
  color: var(--text-body);
  line-height: 1.85;
  margin-bottom: 8px;
}

.article-content-main ol li {
  list-style: decimal;
  font-size: 15px;
  color: var(--text-body);
  line-height: 1.85;
  margin-bottom: 8px;
}

/* 侧边轻量目录 (TOC) */
.article-toc-sticky {
  position: sticky;
  top: 90px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  padding: 24px;
}

.toc-heading {
  font-size: 14px;
  font-weight: 700;
  color: var(--color-slate);
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-light);
}

.toc-nav-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.toc-link {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.5;
  transition: color 0.15s ease;
}

.toc-link:hover, .toc-link.active {
  color: var(--color-slate);
  font-weight: 600;
}

/* 文章底部关联阅读与返回 */
.article-footer-links {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--border-light);
}

.related-reading-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 16px;
}

.related-links-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 28px;
}

.related-link-card {
  padding: 16px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-main);
  transition: border-color 0.15s ease;
}

.related-link-card:hover {
  border-color: var(--color-slate);
}

.related-link-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 4px;
}

.related-link-desc {
  font-size: 12px;
  color: var(--text-muted);
}

/* ==========================================================================
   分类页架构
   ========================================================================== */

.category-page-header {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
  padding: 40px;
  margin-bottom: 36px;
}

.category-h1 {
  font-size: 32px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 14px;
}

.category-desc {
  font-size: 15px;
  color: var(--text-body);
  line-height: 1.85;
  max-width: 820px;
}

.category-articles-wrap {
  border: 1px solid var(--border-light);
  background-color: var(--bg-pure);
}

.category-article-row {
  padding: 28px 32px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  transition: background-color 0.15s ease;
}

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

.category-article-row:hover {
  background-color: var(--bg-alt);
}

.category-article-main {
  max-width: 860px;
}

.cat-article-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 8px;
}

.cat-article-desc {
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.75;
  margin-bottom: 10px;
}

/* ==========================================================================
   Footer (高度 250px-320px，浅色，1px顶部边框)
   ========================================================================== */

.site-footer {
  margin-top: auto;
  background-color: var(--bg-alt);
  border-top: 1px solid var(--border-light);
  padding-top: 48px;
  padding-bottom: 32px;
}

.footer-top-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
  gap: 32px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--border-light);
  margin-bottom: 24px;
}

.footer-brand-col {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.footer-brand-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 6px;
}

.footer-brand-sub {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.footer-col-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 14px;
  letter-spacing: 0.02em;
}

.footer-link-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-link {
  font-size: 13px;
  color: var(--text-body);
  transition: color 0.15s ease;
}

.footer-link:hover {
  color: var(--color-slate);
}

.footer-bottom-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 12px;
  color: var(--text-muted);
}

.footer-friendly-links {
  display: flex;
  align-items: center;
  gap: 16px;
}

.friendly-link {
  color: var(--text-body);
  transition: color 0.15s ease;
}

.friendly-link:hover {
  color: var(--color-slate);
}

/* ==========================================================================
   页面内辅助：信息框与通告
   ========================================================================== */

.notice-box {
  padding: 16px 20px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-alt);
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.75;
  margin-bottom: 24px;
}

/* ==========================================================================
   无障碍与动效支持
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ==========================================================================
   响应式断点体系：1024, 768, 430, 390, 375
   移动端优先消除横向复杂嵌套，确保无横向滚动条
   ========================================================================== */

@media (max-width: 1024px) {
  .hero-nested-grid {
    grid-template-columns: 1fr;
  }
  .plan-select-canvas {
    grid-template-columns: repeat(2, 1fr);
  }
  .plan-sub-zone:nth-child(2) {
    border-right: none;
  }
  .plan-sub-zone:nth-child(1),
  .plan-sub-zone:nth-child(2) {
    border-bottom: 1px solid var(--border-light);
  }
  .lines-top-split {
    grid-template-columns: 1fr;
  }
  .lines-left-explain {
    border-right: none;
    border-bottom: 1px solid var(--border-light);
  }
  .ai-stream-canvas {
    grid-template-columns: 1fr;
  }
  .ai-zone-col {
    border-right: none;
    border-bottom: 1px solid var(--border-light);
  }
  .primary-plan-nested-frame {
    grid-template-columns: 1fr;
  }
  .primary-plan-price-block {
    text-align: left;
    align-items: flex-start;
  }
  .plan-row-item {
    grid-template-columns: 1fr 1fr;
    gap: 12px;
  }
  .plan-row-action {
    text-align: left;
  }
  .footer-top-grid {
    grid-template-columns: 1fr 1fr;
  }
  .footer-brand-col {
    grid-column: 1 / -1;
  }
  .article-body-container {
    grid-template-columns: 1fr;
  }
  .article-toc-sticky {
    position: static;
    margin-bottom: 32px;
  }
}

@media (max-width: 768px) {
  .header-nav, .header-cta-group {
    display: none;
  }
  .mobile-menu-btn {
    display: flex;
  }
  .hero-outer-canvas {
    padding: 28px 20px;
    min-height: auto;
  }
  .hero-h1 {
    font-size: 32px;
  }
  .section-h2 {
    font-size: 24px;
  }
  .plan-select-canvas {
    grid-template-columns: 1fr;
  }
  .plan-sub-zone {
    border-right: none !important;
    border-bottom: 1px solid var(--border-light);
  }
  .node-outer-canvas {
    grid-template-columns: 1fr;
  }
  .node-zone-cell {
    border-right: none !important;
    border-bottom: 1px solid var(--border-light) !important;
  }
  .lines-deep-qa-grid {
    grid-template-columns: 1fr;
  }
  .ai-two-col-list {
    grid-template-columns: 1fr;
  }
  .client-outer-canvas {
    grid-template-columns: 1fr;
  }
  .client-quadrant {
    border-right: none !important;
    border-bottom: 1px solid var(--border-light) !important;
  }
  .pricing-outer-canvas {
    padding: 24px 16px;
  }
  .primary-plan-nested-frame {
    padding: 24px 20px;
  }
  .plan-row-item {
    grid-template-columns: 1fr;
    gap: 8px;
    padding: 16px 0;
  }
  .review-preview-highlights {
    grid-template-columns: 1fr;
  }
  .content-hub-grid {
    grid-template-columns: 1fr;
  }
  .hub-sub-box {
    border-right: none !important;
  }
  .trouble-outer-canvas {
    grid-template-columns: 1fr;
  }
  .trouble-box.large {
    grid-row: auto;
  }
  .trouble-box {
    border-right: none !important;
  }
  .faq-trigger {
    padding: 18px 20px;
    font-size: 15px;
  }
  .faq-answer-panel {
    padding: 0 20px 20px 20px;
  }
  .category-article-row {
    flex-direction: column;
    align-items: flex-start;
    padding: 20px;
  }
  .footer-top-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }
  .footer-bottom-bar {
    flex-direction: column;
    align-items: flex-start;
  }
  .footer-friendly-links {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
}

@media (max-width: 430px) {
  .canvas-wrapper {
    padding-left: 16px;
    padding-right: 16px;
  }
  .hero-h1 {
    font-size: 28px;
  }
  .hero-desc {
    font-size: 15px;
  }
  .article-content-main {
    padding: 28px 18px;
  }
  .article-header-frame {
    padding: 24px 18px;
  }
  .article-h1 {
    font-size: 26px;
  }
}