/* ==========================================================================
   网际快车云 (WJK Cloud) - 第二套: 版芯错栏系统 (Grid/Core Offset-Column System)
   定位: 知识理解型内容站 | 先弄懂，再决定
   ========================================================================== */

:root {
  /* 品牌核心色彩体系 (严格比例: 74% 纸米/白, 12% 森林绿, 7% 胡桃棕, 5% 鼠尾草, 2% 旧金) */
  --bg: #FAF7EF;            /* 主背景: 纸米色 */
  --paper: #FFFDF8;         /* 纸白 */
  --surface: #FFFFFF;       /* 纯白 */
  --text: #272B28;          /* 主文字 */
  --body: #61655F;          /* 正文 */
  --muted: #8B8F88;         /* 次级文字 */
  
  --forest: #374A3D;        /* 森林绿 */
  --forest-dark: #29392F;   /* 深森林绿 */
  --forest-mid: #526358;    /* 中森林绿 */
  
  --walnut: #855D41;        /* 胡桃棕 */
  --walnut-dark: #68462F;   /* 深胡桃 */
  --walnut-soft: #F1E7DF;   /* 浅胡桃 */
  
  --sage: #8A927F;          /* 鼠尾草 */
  --sage-dark: #6B7362;     /* 深鼠尾草 */
  --sage-soft: #ECEEE7;     /* 浅鼠尾草 */
  
  --gold: #AE9567;          /* 旧金 */
  --gold-dark: #8B744E;     /* 深旧金 */
  --gold-soft: #F2ECDE;     /* 浅旧金 */
  
  --border: #DBD4C8;        /* 标准版芯边框 */
  --border-dark: #C8BFB1;   /* 深版芯边框 */
  
  /* 字体与字阶 (编辑排版) */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --font-serif: Georgia, "Times New Roman", "Songti SC", "SimSun", serif;
  
  --radius: 2px;
  --header-height: 72px;
  --max-width: 1380px;
}

/* 基础重置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-sans);
  font-size: 16px;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.8;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

/* 可访问性焦点 */
:focus-visible {
  outline: 2px solid var(--forest);
  outline-offset: 3px;
}

/* 排版基础 */
h1, h2, h3, h4, h5, h6 {
  color: var(--text);
  font-weight: 650;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

h1 {
  font-size: clamp(32px, 4vw, 56px);
  font-weight: 700;
}

h2 {
  font-size: clamp(24px, 2.5vw, 36px);
  font-weight: 650;
}

h3 {
  font-size: clamp(18px, 1.8vw, 24px);
  font-weight: 600;
}

p {
  color: var(--body);
  font-size: 1.0625rem; /* 17px */
  margin-bottom: 1.25rem;
  line-height: 1.85;
}

a {
  color: var(--forest);
  text-decoration: none;
  transition: color 0.2s ease, border-color 0.2s ease;
}

a:hover {
  color: var(--walnut);
}

ul, ol {
  list-style: none;
}

/* 版芯容器 */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* 顶部导航 Header */
.site-header {
  height: var(--header-height);
  background-color: var(--bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
}

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

/* 品牌Logo: 竖版芯线结构 */
.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text);
}

.logo-axis {
  width: 3px;
  height: 28px;
  background-color: var(--gold);
  border-radius: 1px;
  transition: height 0.3s ease, background-color 0.3s ease;
}

.brand-logo:hover .logo-axis {
  background-color: var(--walnut);
  height: 32px;
}

.logo-text-group {
  display: flex;
  flex-direction: column;
}

.logo-title {
  font-size: 1.25rem;
  font-weight: 750;
  letter-spacing: 0.02em;
  color: var(--forest-dark);
  line-height: 1.2;
}

.logo-sub {
  font-size: 0.75rem;
  color: var(--muted);
  letter-spacing: 0.05em;
}

/* Header 导航菜单 */
.main-nav {
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-link {
  font-size: 0.9375rem;
  color: var(--body);
  font-weight: 500;
  padding: 6px 0;
  position: relative;
  display: flex;
  align-items: center;
}

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

/* 当前激活项: 森林绿文字 + 侧面旧金竖线 */
.nav-link.active {
  color: var(--forest);
  font-weight: 650;
}

.nav-link.active::before {
  content: "";
  display: inline-block;
  width: 3px;
  height: 12px;
  background-color: var(--gold);
  margin-right: 6px;
}

/* 商业 CTA 按钮 */
.cta-button-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 22px;
  background-color: var(--forest);
  color: #FFFFFF !important;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius);
  border: 1px solid var(--forest-dark);
  transition: all 0.25s ease;
  cursor: pointer;
  white-space: nowrap;
}

.cta-button-primary:hover {
  background-color: var(--forest-dark);
  color: #FFFFFF !important;
  transform: translateY(-1px);
}

.cta-link-secondary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--walnut);
  font-weight: 600;
  font-size: 0.9375rem;
  padding: 8px 16px;
  border: 1px solid var(--border);
  background-color: var(--paper);
  border-radius: var(--radius);
  transition: all 0.2s ease;
}

.cta-link-secondary:hover {
  border-color: var(--walnut);
  background-color: var(--surface);
  color: var(--walnut-dark);
}

/* 移动端菜单按钮 */
.mobile-menu-btn {
  display: none;
  background: none;
  border: 1px solid var(--border);
  padding: 8px 12px;
  font-size: 0.9rem;
  color: var(--text);
  border-radius: var(--radius);
  cursor: pointer;
}

/* ==========================================================================
   00. HERO: 版芯错栏Hero (Asymmetric Core Grid)
   ========================================================================== */
.hero-section {
  padding: 48px 0 64px 0;
  border-bottom: 1px solid var(--border);
  background-color: var(--bg);
}

.hero-offset-grid {
  display: grid;
  grid-template-columns: 34fr 18fr 48fr;
  gap: 32px;
  position: relative;
}

.hero-axis-line {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 1px;
  background-color: var(--border);
}

.hero-axis-line.line-1 { left: 34%; }
.hero-axis-line.line-2 { left: 52%; }

/* Hero 第一栏: 概念引导 */
.hero-col-1 {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.hero-kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--walnut);
  font-weight: 650;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero-kicker::before {
  content: "";
  width: 12px;
  height: 2px;
  background-color: var(--gold);
}

.hero-headline {
  font-size: clamp(38px, 4.5vw, 54px);
  color: var(--forest-dark);
  font-weight: 750;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.hero-concept-preview {
  margin-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-left: 16px;
  border-left: 2px solid var(--sage);
}

.hero-concept-item {
  font-size: 1.0625rem;
  color: var(--text);
  font-weight: 600;
}

/* Hero 第二栏: 窄索引栏 */
.hero-col-2 {
  display: flex;
  flex-direction: column;
  padding: 0 12px;
  border-left: 1px dashed var(--border-dark);
  border-right: 1px dashed var(--border-dark);
}

.index-label {
  font-size: 0.8125rem;
  color: var(--muted);
  letter-spacing: 0.1em;
  margin-bottom: 16px;
  font-weight: 600;
}

.hero-index-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.hero-index-item {
  font-size: 0.9375rem;
  color: var(--body);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.hero-index-item span:first-child {
  font-weight: 600;
  color: var(--forest);
}

/* Hero 第三栏: 核心H1与主说明 */
.hero-col-3 {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.hero-h1-title {
  font-size: clamp(22px, 2.2vw, 30px);
  color: var(--text);
  font-weight: 700;
  margin-bottom: 20px;
  line-height: 1.4;
  border-bottom: 2px solid var(--gold);
  padding-bottom: 16px;
}

.hero-body-text {
  font-size: 1.0625rem;
  color: var(--body);
  line-height: 1.9;
  margin-bottom: 28px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  margin-top: 16px;
}

/* ==========================================================================
   通用Section 布局规则 (错栏差异化)
   ========================================================================== */
.section-block {
  padding: 72px 0;
  border-bottom: 1px solid var(--border);
  position: relative;
}

.section-block:nth-child(even) {
  background-color: var(--paper);
}

/* 编号标题线 */
.section-header-wrap {
  margin-bottom: 40px;
}

.section-num {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--gold-dark);
  font-family: var(--font-sans);
  letter-spacing: 0.05em;
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}

.section-num::after {
  content: "";
  flex: 1;
  max-width: 80px;
  height: 1px;
  background-color: var(--gold);
}

.section-title {
  font-size: clamp(26px, 2.8vw, 36px);
  color: var(--forest-dark);
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--muted);
  margin-top: 6px;
  font-weight: 400;
}

/* 规则回答突显框 (GEO / AI 理解型) */
.direct-answer-box {
  background-color: var(--sage-soft);
  border-left: 4px solid var(--forest);
  padding: 20px 24px;
  margin-bottom: 32px;
  border-radius: var(--radius);
}

.direct-answer-box p {
  color: var(--forest-dark);
  font-weight: 500;
  font-size: 1.0625rem;
  margin-bottom: 0;
}

/* ==========================================================================
   01 / 基础概念Section (22% / 48% / 30% 错栏)
   ========================================================================== */
.concepts-offset-grid {
  display: grid;
  grid-template-columns: 22fr 48fr 30fr;
  gap: 36px;
}

.concepts-col-left h3 {
  font-size: 1.5rem;
  color: var(--forest-dark);
  line-height: 1.4;
  position: sticky;
  top: 100px;
}

.concept-entry-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.concept-entry-item {
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
}

.concept-term {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--walnut-dark);
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.concept-term::before {
  content: "■";
  font-size: 0.6rem;
  color: var(--gold);
}

.concept-desc {
  font-size: 1rem;
  color: var(--body);
  margin-bottom: 0;
}

.concepts-col-right {
  background-color: var(--bg);
  padding: 24px;
  border: 1px solid var(--border);
  height: fit-content;
}

.concepts-col-right h4 {
  font-size: 1.125rem;
  color: var(--forest-dark);
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--gold);
}

/* ==========================================================================
   02 / 知识关系表 <table>
   ========================================================================== */
.table-editorial-wrapper {
  overflow-x: auto;
  margin-top: 24px;
  border-top: 2px solid var(--forest);
  border-bottom: 2px solid var(--forest);
}

.table-editorial {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.98rem;
}

.table-editorial th {
  background-color: var(--forest-dark);
  color: #FFFFFF;
  padding: 16px 20px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.table-editorial td {
  padding: 18px 20px;
  border-bottom: 1px solid var(--border);
  color: var(--body);
  vertical-align: top;
}

.table-editorial tr:nth-child(even) td {
  background-color: rgba(236, 238, 231, 0.4);
}

.table-editorial .concept-tag {
  font-weight: 700;
  color: var(--forest-dark);
  font-size: 1.0625rem;
}

.table-editorial .misconception-text {
  color: var(--walnut);
}

/* ==========================================================================
   03 / 节点地区知识 (28% / 44% / 28% 错栏)
   ========================================================================== */
.region-offset-grid {
  display: grid;
  grid-template-columns: 28fr 44fr 28fr;
  gap: 32px;
}

.region-col-side {
  border-right: 1px solid var(--border);
  padding-right: 24px;
}

.region-col-right-misconception {
  border-left: 1px solid var(--border);
  padding-left: 24px;
  background-color: var(--gold-soft);
  padding: 24px;
}

.region-col-right-misconception h4 {
  color: var(--walnut-dark);
  margin-bottom: 12px;
  font-size: 1.125rem;
}

/* ==========================================================================
   04 / 地区词条 (错栏词条版)
   ========================================================================== */
.region-entry-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.region-dictionary-card {
  padding: 28px;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--forest);
  transition: transform 0.2s ease;
}

.region-dictionary-card:hover {
  transform: translateY(-2px);
}

.region-card-title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.region-card-title h3 {
  font-size: 1.625rem;
  color: var(--forest-dark);
}

.region-card-badge {
  font-size: 0.8125rem;
  color: var(--walnut);
  background-color: var(--walnut-soft);
  padding: 4px 10px;
  font-weight: 600;
}

/* ==========================================================================
   05 / 线路知识 (直连, 中转, IEPL, IPLC)
   ========================================================================== */
.line-types-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-bottom: 36px;
}

.line-type-col {
  background-color: var(--paper);
  border: 1px solid var(--border);
  padding: 24px 20px;
  position: relative;
}

.line-type-col::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background-color: var(--gold);
}

.line-type-name {
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--forest-dark);
  margin-bottom: 8px;
}

.line-type-sub {
  font-size: 0.875rem;
  color: var(--muted);
  margin-bottom: 16px;
}

/* ==========================================================================
   06 / 客户端, 订阅, 配置, 节点关系 (编号01-04逻辑)
   ========================================================================== */
.relationship-flow-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.flow-step-item {
  background-color: var(--surface);
  border: 1px solid var(--border);
  padding: 24px;
  display: flex;
  flex-direction: column;
}

.flow-step-num {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--gold);
  line-height: 1;
  margin-bottom: 12px;
  font-family: var(--font-sans);
}

.flow-step-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--forest-dark);
  margin-bottom: 10px;
}

/* ==========================================================================
   07 / 设备系统 (错栏大标题词条: 56% / 44%)
   ========================================================================== */
.devices-offset-layout {
  display: grid;
  grid-template-columns: 56fr 44fr;
  gap: 32px;
}

.device-box {
  padding: 28px;
  background-color: var(--paper);
  border: 1px solid var(--border);
}

.device-box.windows-box {
  border-top: 4px solid var(--forest);
}

.device-box.mac-box {
  border-top: 4px solid var(--walnut);
}

.device-box.android-box {
  border-top: 4px solid var(--sage-dark);
}

.device-box.iphone-box {
  border-top: 4px solid var(--gold);
}

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

.device-name {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
}

.device-tag {
  font-size: 0.8125rem;
  color: var(--muted);
  border: 1px solid var(--border);
  padding: 2px 8px;
}

/* ==========================================================================
   08 / AI与流媒体 (平台知识双版芯)
   ========================================================================== */
.platform-dual-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 36px;
}

.platform-block {
  padding: 32px;
  background-color: var(--surface);
  border: 1px solid var(--border);
}

.platform-block h3 {
  font-size: 1.5rem;
  color: var(--forest-dark);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--gold);
}

.platform-tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 20px;
}

.platform-tag {
  font-size: 0.875rem;
  background-color: var(--bg);
  color: var(--forest);
  padding: 4px 12px;
  border: 1px solid var(--border);
  font-weight: 600;
}

/* ==========================================================================
   09 / 常见概念误区 (概念注释边栏: ≠ 关系)
   ========================================================================== */
.mistakes-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.mistake-item {
  background-color: var(--paper);
  border: 1px solid var(--border);
  padding: 24px;
  position: relative;
}

.mistake-equation {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.125rem;
  font-weight: 750;
  color: var(--walnut-dark);
  margin-bottom: 12px;
  background-color: var(--walnut-soft);
  padding: 8px 12px;
  border-radius: var(--radius);
}

.mistake-not-equal {
  color: #C0392B;
  font-size: 1.3rem;
  font-weight: 900;
}

/* ==========================================================================
   10 / 知识型深度评测 (百科版芯摘要)
   ========================================================================== */
.review-summary-block {
  background-color: var(--paper);
  border: 2px solid var(--forest);
  padding: 40px;
  display: grid;
  grid-template-columns: 24fr 48fr 28fr;
  gap: 32px;
}

.review-summary-col-1 h4 {
  font-size: 1.125rem;
  color: var(--gold-dark);
  margin-bottom: 16px;
}

.review-summary-col-2 h3 {
  font-size: 1.75rem;
  color: var(--forest-dark);
  margin-bottom: 16px;
  line-height: 1.35;
}

.review-summary-col-3 {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background-color: var(--sage-soft);
  padding: 24px;
  border: 1px solid var(--border);
}

/* ==========================================================================
   11 / 编辑价目页 (5档方案 - 错栏横向编辑段落)
   ========================================================================== */
.pricing-editorial-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-top: 32px;
}

.pricing-row-item {
  display: grid;
  grid-template-columns: 80px 180px 1fr 140px 160px 160px;
  align-items: center;
  padding: 24px 28px;
  background-color: var(--surface);
  border: 1px solid var(--border);
  gap: 20px;
  transition: all 0.2s ease;
}

.pricing-row-item:hover {
  border-color: var(--forest);
}

/* 主力推荐方案: 浅鼠尾草背景 #ECEEE7 + 旧金短线 + 胡桃棕标签 */
.pricing-row-item.featured {
  background-color: var(--sage-soft);
  border: 2px solid var(--forest);
  position: relative;
}

.pricing-row-item.featured::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 6px;
  background-color: var(--gold);
}

.pricing-num {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--muted);
  font-family: var(--font-sans);
}

.pricing-title-wrap {
  display: flex;
  flex-direction: column;
}

.pricing-title {
  font-size: 1.25rem;
  font-weight: 750;
  color: var(--forest-dark);
}

.pricing-badge-recommend {
  display: inline-block;
  font-size: 0.75rem;
  background-color: var(--walnut);
  color: #FFFFFF;
  padding: 2px 8px;
  border-radius: var(--radius);
  margin-top: 4px;
  width: fit-content;
  font-weight: 600;
}

.pricing-desc {
  font-size: 0.9375rem;
  color: var(--body);
  margin-bottom: 0;
}

.pricing-data {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text);
}

.pricing-price {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--forest-dark);
  font-family: var(--font-sans);
}

.pricing-price span {
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--muted);
}

/* ==========================================================================
   12 / 知识文章中心 (编辑目录索引)
   ========================================================================== */
.articles-index-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 40px;
}

.articles-category-nav {
  display: flex;
  flex-direction: column;
  gap: 12px;
  position: sticky;
  top: 100px;
}

.category-nav-item {
  padding: 10px 16px;
  background-color: var(--paper);
  border: 1px solid var(--border);
  color: var(--body);
  font-weight: 600;
  font-size: 0.9375rem;
  border-radius: var(--radius);
  transition: all 0.2s ease;
}

.category-nav-item:hover, .category-nav-item.active {
  background-color: var(--forest);
  color: #FFFFFF;
  border-color: var(--forest-dark);
}

.articles-list-container {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.article-row-card {
  padding: 24px;
  background-color: var(--surface);
  border: 1px solid var(--border);
  display: grid;
  grid-template-columns: 60px 1fr 140px;
  gap: 20px;
  align-items: flex-start;
}

.article-row-card:hover {
  border-color: var(--forest);
}

.article-row-num {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--gold-dark);
}

.article-row-content h3 {
  font-size: 1.25rem;
  color: var(--forest-dark);
  margin-bottom: 8px;
}

.article-row-content p {
  font-size: 0.9375rem;
  margin-bottom: 12px;
}

.article-meta {
  display: flex;
  gap: 16px;
  font-size: 0.8125rem;
  color: var(--muted);
}

/* ==========================================================================
   13 / 常见问题 FAQ (词条问答索引 accordion)
   ========================================================================== */
.faq-accordion-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 24px;
}

.faq-item {
  border: 1px solid var(--border);
  background-color: var(--surface);
  border-radius: var(--radius);
  overflow: hidden;
}

.faq-question-btn {
  width: 100%;
  padding: 20px 24px;
  background: none;
  border: none;
  text-align: left;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 1.125rem;
  font-weight: 650;
  color: var(--text);
  cursor: pointer;
  transition: background-color 0.2s ease;
}

.faq-question-btn:hover {
  background-color: var(--bg);
  color: var(--forest);
}

.faq-icon-toggle {
  font-size: 1.5rem;
  color: var(--gold-dark);
  font-weight: 300;
  transition: transform 0.3s ease;
}

.faq-item.open .faq-icon-toggle {
  transform: rotate(45deg);
}

.faq-answer-panel {
  display: none;
  padding: 0 24px 20px 24px;
  color: var(--body);
  font-size: 1rem;
  line-height: 1.8;
  border-top: 1px dashed var(--border);
  margin-top: 4px;
  padding-top: 16px;
}

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

/* ==========================================================================
   文章详情页 (Single Article Layout)
   ========================================================================== */
.article-page-wrap {
  padding: 48px 0 80px 0;
}

.article-header {
  max-width: 820px;
  margin: 0 auto 40px auto;
}

.breadcrumb-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--muted);
  margin-bottom: 20px;
}

.breadcrumb-nav a {
  color: var(--muted);
}

.breadcrumb-nav a:hover {
  color: var(--forest);
}

.article-main-h1 {
  font-size: clamp(28px, 3.2vw, 44px);
  color: var(--forest-dark);
  margin-bottom: 16px;
  line-height: 1.3;
}

.article-summary-lead {
  font-size: 1.1875rem;
  color: var(--body);
  line-height: 1.85;
  margin-bottom: 24px;
  font-weight: 450;
}

.article-meta-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 20px;
  padding: 14px 20px;
  background-color: var(--paper);
  border: 1px solid var(--border);
  font-size: 0.875rem;
  color: var(--muted);
}

.article-layout-grid {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 48px;
  max-width: 1160px;
  margin: 0 auto;
}

.article-content-body {
  max-width: 800px;
  background-color: var(--paper);
  padding: 40px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.article-content-body h2 {
  font-size: 1.75rem;
  color: var(--forest-dark);
  margin: 40px 0 20px 0;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--gold);
}

.article-content-body h3 {
  font-size: 1.375rem;
  color: var(--text);
  margin: 28px 0 16px 0;
}

.article-content-body ul, .article-content-body ol {
  margin: 16px 0 24px 24px;
}

.article-content-body ul { list-style: disc; }
.article-content-body ol { list-style: decimal; }

.article-content-body li {
  margin-bottom: 8px;
  color: var(--body);
}

/* 文章右侧目录 (TOC Sidebar) */
.article-toc-sidebar {
  position: sticky;
  top: 100px;
  height: fit-content;
  background-color: var(--paper);
  border: 1px solid var(--border);
  padding: 24px;
}

.toc-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--forest-dark);
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-size: 0.875rem;
}

.toc-list a {
  color: var(--body);
  line-height: 1.4;
}

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

/* 文章相关阅读 box */
.related-articles-box {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 2px solid var(--forest);
}

.related-articles-box h4 {
  font-size: 1.25rem;
  color: var(--forest-dark);
  margin-bottom: 16px;
}

/* ==========================================================================
   Footer: 森林绿知识目录Footer (#29392F background, #FBF9F2 text)
   ========================================================================== */
.site-footer {
  background-color: var(--forest-dark);
  color: #FBF9F2;
  padding: 64px 0 32px 0;
  margin-top: auto;
  border-top: 3px solid var(--gold);
}

.footer-grid {
  display: grid;
  grid-template-columns: 320px repeat(4, 1fr);
  gap: 40px;
  margin-bottom: 48px;
}

.footer-brand-col {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  color: #FFFFFF;
  text-decoration: none;
}

.footer-axis {
  width: 3px;
  height: 28px;
  background-color: var(--gold);
}

.footer-brand-name {
  font-size: 1.375rem;
  font-weight: 800;
  color: #FFFFFF;
}

.footer-tagline {
  font-size: 0.875rem;
  color: #CCD2C8;
  line-height: 1.6;
}

.footer-col h4 {
  color: #FFFFFF;
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 20px;
  position: relative;
  padding-bottom: 8px;
}

.footer-col h4::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 20px;
  height: 2px;
  background-color: var(--gold);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-links a {
  color: #CCD2C8;
  font-size: 0.9375rem;
  transition: color 0.2s ease;
}

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

/* 友情链接区 */
.friendship-links-wrap {
  padding-top: 24px;
  border-top: 1px solid rgba(219, 212, 200, 0.2);
  margin-bottom: 24px;
}

.friendship-links-title {
  font-size: 0.875rem;
  color: var(--gold);
  font-weight: 600;
  margin-bottom: 12px;
}

.friendship-links-list {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
}

.friendship-links-list a {
  color: #CCD2C8;
  font-size: 0.875rem;
}

.friendship-links-list a:hover {
  color: #FFFFFF;
}

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid rgba(219, 212, 200, 0.15);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.875rem;
  color: #9AA096;
}

/* ==========================================================================
   响应式调整 (Responsive Breakpoints: 1440, 1024, 768, 430, 390, 375)
   ========================================================================== */
@media (max-width: 1200px) {
  .pricing-row-item {
    grid-template-columns: 60px 160px 1fr 120px 140px 140px;
  }
}

@media (max-width: 1024px) {
  .hero-offset-grid {
    grid-template-columns: 1fr 1fr;
  }
  .hero-col-2 {
    display: none; /* 平板端缩减第二栏 */
  }
  .concepts-offset-grid, .region-offset-grid {
    grid-template-columns: 1fr 1fr;
  }
  .region-col-right-misconception {
    grid-column: span 2;
  }
  .line-types-grid, .relationship-flow-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .mistakes-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-row-item {
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    padding: 20px;
  }
  .pricing-num { display: none; }
  .articles-index-layout {
    grid-template-columns: 1fr;
  }
  .articles-category-nav {
    flex-direction: row;
    position: static;
    overflow-x: auto;
  }
  .article-layout-grid {
    grid-template-columns: 1fr;
  }
  .article-toc-sidebar {
    display: none; /* 移动端隐藏侧栏目录 */
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .main-nav {
    display: none; /* 移动端下拉 */
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 20px;
    gap: 14px;
    align-items: flex-start;
  }
  .main-nav.show {
    display: flex;
  }
  .mobile-menu-btn {
    display: block;
  }
  .hero-offset-grid {
    grid-template-columns: 1fr;
  }
  .concepts-offset-grid, .region-offset-grid, .devices-offset-layout, .platform-dual-grid {
    grid-template-columns: 1fr;
  }
  .region-entry-grid {
    grid-template-columns: 1fr;
  }
  .line-types-grid, .relationship-flow-grid, .mistakes-grid {
    grid-template-columns: 1fr;
  }
  .review-summary-block {
    grid-template-columns: 1fr;
    padding: 24px;
  }
  .pricing-row-item {
    grid-template-columns: 1fr;
  }
  .article-row-card {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

/* Preferences Reduced Motion */
@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;
  }
}