/* ==================================================
   赔钱机场 · 预算 × 用途矩阵 核心样式表
   Set 3 专属：二维矩阵 / 交叉坐标 / 细网格 / 冷白商务技术风
================================================== */

:root {
  /* 基础配色规范 (70% 冷白/纯白, 20% 深蓝灰/墨黑/青绿, 10% 焦橙) */
  --bg-main: #F6F8F8;
  --bg-white: #FFFFFF;
  --bg-alt: #F0F3F3;
  --bg-footer: #EBEFEF;
  
  --text-main: #182126;
  --text-body: #556168;
  --text-sub: #869197;
  --text-footer: #465159;
  
  --color-primary: #355F71;       /* 深蓝灰 */
  --color-primary-dark: #294B59;  /* 深蓝 */
  --color-accent: #48796E;        /* 青绿 */
  --color-accent-orange: #B86F48; /* 焦橙 (重点提亮) */
  
  --color-tag-blue: #EBF1F3;      /* 浅蓝 */
  --color-tag-green: #ECF3F0;     /* 浅绿 (主力高亮) */
  --color-tag-orange: #F6EDE7;    /* 浅橙 */
  
  --border-color: #DDE3E4;
  --border-strong: #355F71;
  --border-accent: #48796E;
  
  /* 字体族 */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  
  /* 容器宽度与间距 */
  --container-max: 1220px;
  --article-max: 820px;
  --header-height: 70px;
  
  /* 阴影与转场 (极克制) */
  --shadow-sm: 0 1px 3px rgba(24, 33, 38, 0.05);
  --shadow-md: 0 4px 12px rgba(24, 33, 38, 0.06);
  --transition-fast: 0.15s ease-in-out;
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-body);
  line-height: 1.8;
  font-size: 1rem;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* 标题样式规范 */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

h1 {
  font-size: clamp(2.2rem, 4vw, 3.2rem); /* 44px - 58px 范围内 */
  font-weight: 800;
}

h2 {
  font-size: clamp(1.6rem, 2.8vw, 2.1rem); /* 28px - 36px 范围内 */
  margin-bottom: 0.75rem;
}

h3 {
  font-size: clamp(1.2rem, 2vw, 1.5rem); /* 20px - 26px 范围内 */
  margin-bottom: 0.5rem;
}

p {
  margin-bottom: 1.25rem;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-accent-orange);
}

/* 通用容器 */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.25rem;
  padding-right: 1.25rem;
}

.article-container {
  width: 100%;
  max-width: var(--article-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.25rem;
  padding-right: 1.25rem;
}

/* 标签与小徽章 */
.section-badge {
  display: inline-flex;
  align-items: center;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-primary);
  background-color: var(--color-tag-blue);
  border: 1px solid var(--border-color);
  padding: 0.2rem 0.65rem;
  border-radius: 2px;
  text-transform: none;
  letter-spacing: 0.04em;
  margin-bottom: 0.75rem;
}

.tag-highlight {
  display: inline-block;
  background-color: var(--color-accent-orange);
  color: #FFFFFF;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.15rem 0.5rem;
  border-radius: 2px;
  line-height: 1.2;
}

.tag-neutral {
  display: inline-block;
  background-color: var(--bg-alt);
  color: var(--text-body);
  font-size: 0.75rem;
  padding: 0.15rem 0.5rem;
  border: 1px solid var(--border-color);
  border-radius: 2px;
}

.tag-teal {
  display: inline-block;
  background-color: var(--color-tag-green);
  color: var(--color-accent);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.15rem 0.5rem;
  border: 1px solid rgba(72, 121, 110, 0.3);
  border-radius: 2px;
}

/* 顶部导航栏 Header (66px-72px, 纯白, 1px底边框) */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
}

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

/* Logo: 四格矩阵 + 一个高亮网络节点 */
.brand-logo-wrap {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
}

.logo-svg {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

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

.brand-title {
  font-size: 1.125rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.brand-sub {
  font-size: 0.6875rem;
  color: var(--text-sub);
  letter-spacing: 0.02em;
  margin-top: 1px;
}

/* 桌面导航链接 */
.desktop-nav {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.nav-link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-body);
  position: relative;
  padding: 0.5rem 0;
  transition: color var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary-dark);
}

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

/* 商业 CTA 按钮规范 */
.btn-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  background-color: var(--color-primary);
  color: #FFFFFF;
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.55rem 1.15rem;
  border-radius: 2px;
  border: 1px solid var(--color-primary-dark);
  transition: background-color var(--transition-fast), transform var(--transition-fast);
  white-space: nowrap;
}

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

.btn-cta:hover .btn-arrow {
  transform: translateX(3px);
}

.btn-arrow {
  transition: transform var(--transition-fast);
}

.btn-cta-orange {
  background-color: var(--color-accent-orange);
  border-color: #9c5c3b;
}

.btn-cta-orange:hover {
  background-color: #a45f3a;
  color: #FFFFFF;
}

.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border: 1px solid var(--border-color);
}

.btn-outline:hover {
  background-color: var(--bg-alt);
  color: var(--color-primary-dark);
  border-color: var(--color-primary);
}

/* 移动端菜单按钮与抽屉 */
.mobile-menu-btn {
  display: none;
  background: none;
  border: 1px solid var(--border-color);
  padding: 0.45rem 0.75rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-main);
  border-radius: 2px;
  cursor: pointer;
}

.mobile-nav-drawer {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--bg-white);
  padding: 1.5rem;
  z-index: 999;
  overflow-y: auto;
  border-top: 1px solid var(--border-color);
}

.mobile-nav-drawer.open {
  display: block;
}

.mobile-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.mobile-nav-list a {
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-main);
  display: block;
  padding: 0.4rem 0;
  border-bottom: 1px dashed var(--border-color);
}

.mobile-nav-cta {
  margin-top: 1.5rem;
  display: block;
  text-align: center;
}

/* ==================================================
   Hero 决策区域 (预算 × 用途决策矩阵)
================================================== */
.hero-section {
  padding: 2.5rem 0 3.5rem;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-main);
}

.hero-meta-top {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.hero-h1-sr {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.hero-headline {
  font-size: clamp(2rem, 3.8vw, 3rem);
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.25;
  margin-bottom: 0.6rem;
  white-space: pre-line;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--color-primary);
  font-weight: 600;
  margin-bottom: 1rem;
}

.hero-body-text {
  font-size: 1.025rem;
  color: var(--text-body);
  max-width: 920px;
  line-height: 1.85;
  margin-bottom: 1.5rem;
}

.hero-action-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.85rem;
  margin-bottom: 2.25rem;
}

/* 核心：Hero 二维矩阵 (5 × 4 交叉表) */
.hero-matrix-wrapper {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 2px;
  box-shadow: var(--shadow-sm);
  overflow-x: auto;
}

.matrix-caption-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.65rem 1rem;
  background-color: var(--bg-alt);
  border-bottom: 1px solid var(--border-color);
  font-size: 0.8125rem;
  color: var(--text-sub);
}

.matrix-caption-bar .caption-label {
  font-weight: 600;
  color: var(--color-primary);
}

.matrix-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.875rem;
}

.matrix-table th,
.matrix-table td {
  border: 1px solid var(--border-color);
  padding: 0.85rem 1rem;
  vertical-align: middle;
}

/* 表头：左上角交叉角格 */
.matrix-corner-th {
  background-color: var(--bg-alt);
  width: 130px;
  color: var(--text-main);
  font-weight: 700;
  font-size: 0.8125rem;
}

/* 表头：列标题 (强度) */
.matrix-col-th {
  background-color: var(--bg-alt);
  color: var(--text-main);
  font-weight: 700;
  text-align: center;
  width: 21.75%;
}

.matrix-col-th.col-featured {
  background-color: var(--color-tag-green);
  border-top: 3px solid var(--color-accent);
  color: var(--color-accent);
}

/* 行标题 (用途) */
.matrix-row-th {
  background-color: var(--bg-alt);
  color: var(--text-main);
  font-weight: 700;
  font-size: 0.875rem;
}

/* 单元格内容布局 */
.matrix-cell {
  background-color: var(--bg-white);
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
  cursor: default;
}

.matrix-cell:hover {
  background-color: #F8FAF9;
}

/* 主力列高亮格 */
.matrix-cell.cell-featured {
  background-color: var(--color-tag-green);
}

.matrix-cell.cell-featured:hover {
  background-color: #E2ECE8;
}

.cell-inner {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.cell-traffic {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-main);
  font-family: var(--font-mono);
  letter-spacing: -0.02em;
}

.cell-featured .cell-traffic {
  color: var(--color-accent);
}

.cell-price {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-primary);
}

.cell-tag {
  font-size: 0.725rem;
  color: var(--text-sub);
}

/* 矩阵底部说明 */
.matrix-footnote {
  padding: 0.65rem 1rem;
  background-color: var(--bg-alt);
  border-top: 1px solid var(--border-color);
  font-size: 0.775rem;
  color: var(--text-sub);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

/* 移动端 Hero 矩阵专用分组容器 (桌面隐藏) */
.hero-matrix-mobile {
  display: none;
}

/* ==================================================
   通用模块规范
================================================== */
.page-section {
  padding: 3.5rem 0;
  border-bottom: 1px solid var(--border-color);
}

.page-section:nth-child(even) {
  background-color: var(--bg-alt);
}

.section-header {
  margin-bottom: 2rem;
}

.section-desc {
  font-size: 1.025rem;
  color: var(--text-body);
  max-width: 860px;
}

/* ==================================================
   01 / 使用强度横轴
================================================== */
.intensity-axis {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 2px;
  padding: 2rem 1.5rem;
  position: relative;
}

.axis-track {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  position: relative;
  gap: 1.5rem;
}

/* 强度轴连接线 */
.axis-track::before {
  content: "";
  position: absolute;
  top: 18px;
  left: 12.5%;
  right: 12.5%;
  height: 2px;
  background-color: var(--border-color);
  z-index: 1;
}

.axis-node {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  position: relative;
  z-index: 2;
}

.node-dot {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background-color: var(--bg-white);
  border: 2px solid var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.8125rem;
  color: var(--color-primary);
  margin-bottom: 0.75rem;
  transition: all var(--transition-fast);
}

.axis-node.active .node-dot {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: #FFFFFF;
}

.axis-node-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 0.4rem;
}

.axis-node-desc {
  font-size: 0.85rem;
  color: var(--text-body);
  line-height: 1.6;
}

/* ==================================================
   数据对比表格 / 矩阵 Table 通用样式
================================================== */
.matrix-table-wrap {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 2px;
  overflow-x: auto;
  box-shadow: var(--shadow-sm);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

.data-table th,
.data-table td {
  padding: 0.9rem 1.1rem;
  border: 1px solid var(--border-color);
  vertical-align: middle;
}

.data-table th {
  background-color: var(--bg-alt);
  color: var(--text-main);
  font-weight: 700;
  white-space: nowrap;
}

.data-table tr:hover td {
  background-color: #FAFCFC;
}

.col-strong {
  font-weight: 700;
  color: var(--text-main);
}

.col-mono {
  font-family: var(--font-mono);
  font-weight: 700;
}

/* ==================================================
   08 / 套餐方案矩阵 (核心商业区)
================================================== */
.plans-matrix-container {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 2px;
  overflow-x: auto;
  box-shadow: var(--shadow-sm);
  margin-bottom: 1.5rem;
}

.plan-table {
  width: 100%;
  border-collapse: collapse;
  table-layout: fixed;
}

.plan-table th,
.plan-table td {
  padding: 1rem 1.15rem;
  border: 1px solid var(--border-color);
  vertical-align: middle;
}

.plan-param-th {
  width: 130px;
  background-color: var(--bg-alt);
  color: var(--text-main);
  font-weight: 700;
  font-size: 0.875rem;
}

.plan-col-th {
  background-color: var(--bg-alt);
  text-align: center;
  padding: 1.25rem 1rem;
}

.plan-col-th.col-mainstream {
  background-color: var(--color-tag-green);
  border-top: 4px solid var(--color-accent);
}

.plan-title-lg {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 0.35rem;
}

.plan-col-th.col-mainstream .plan-title-lg {
  color: var(--color-accent);
}

.plan-price-num {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--text-main);
  font-family: var(--font-mono);
  letter-spacing: -0.02em;
}

.plan-col-th.col-mainstream .plan-price-num {
  color: var(--color-primary-dark);
}

.plan-table td.col-mainstream {
  background-color: var(--color-tag-green);
}

.plan-table td {
  text-align: center;
}

.cell-plan-data {
  font-weight: 600;
  color: var(--text-main);
}

.cell-plan-cta {
  padding: 1.25rem 1rem !important;
}

/* 独立长期备用方案 */
.backup-plan-banner {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--color-primary);
  border-radius: 2px;
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  box-shadow: var(--shadow-sm);
}

.backup-info-group {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.backup-title {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-main);
}

.backup-price {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--color-primary-dark);
  font-family: var(--font-mono);
}

.backup-traffic {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-main);
  background-color: var(--bg-alt);
  padding: 0.2rem 0.6rem;
  border: 1px solid var(--border-color);
  border-radius: 2px;
}

.backup-desc {
  font-size: 0.875rem;
  color: var(--text-sub);
}

/* 移动端方案堆叠布局 (桌面隐藏) */
.mobile-plans-list {
  display: none;
}

/* ==================================================
   10 / 内容匹配矩阵 (6 行 × 4 列)
================================================== */
.content-matrix-table {
  width: 100%;
  border-collapse: collapse;
}

.content-matrix-table th,
.content-matrix-table td {
  border: 1px solid var(--border-color);
  padding: 0.85rem 1rem;
  vertical-align: top;
}

.content-category-th {
  background-color: var(--bg-alt);
  width: 120px;
  font-weight: 700;
  color: var(--text-main);
  font-size: 0.875rem;
}

.content-col-th {
  background-color: var(--bg-alt);
  font-weight: 700;
  color: var(--text-main);
  text-align: center;
  font-size: 0.875rem;
}

.content-matrix-cell {
  background-color: var(--bg-white);
  transition: background-color var(--transition-fast);
}

.content-matrix-cell:hover {
  background-color: #F8FAFA;
}

.article-matrix-link {
  display: block;
  text-decoration: none;
}

.article-matrix-title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 0.35rem;
  line-height: 1.45;
  transition: color var(--transition-fast);
}

.article-matrix-link:hover .article-matrix-title {
  color: var(--color-accent-orange);
}

.article-matrix-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-sub);
}

.article-read-text {
  color: var(--color-primary);
  font-weight: 600;
}

/* ==================================================
   11 / 网络排障步骤指示
================================================== */
.troubleshoot-steps {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.step-card {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  padding: 0.75rem 0.5rem;
  text-align: center;
  border-radius: 2px;
}

.step-num {
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--color-primary);
  font-family: var(--font-mono);
  margin-bottom: 0.2rem;
}

.step-name {
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--text-main);
}

/* ==================================================
   12 / 常见问题 (FAQ 矩阵问答)
================================================== */
.faq-matrix-wrap {
  border: 1px solid var(--border-color);
  background-color: var(--bg-white);
  border-radius: 2px;
}

.faq-item {
  border-bottom: 1px solid var(--border-color);
  transition: background-color var(--transition-fast);
}

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

.faq-summary {
  display: grid;
  grid-template-columns: 50px 1fr 30px;
  align-items: center;
  padding: 1rem 1.25rem;
  cursor: pointer;
  list-style: none;
  user-select: none;
}

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

.faq-id {
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--color-primary);
  font-family: var(--font-mono);
}

.faq-question {
  font-size: 1.025rem;
  font-weight: 700;
  color: var(--text-main);
}

.faq-icon {
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--text-sub);
  text-align: right;
  transition: transform var(--transition-fast);
}

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

.faq-answer {
  padding: 0 1.25rem 1.25rem 50px;
  color: var(--text-body);
  font-size: 0.95rem;
  line-height: 1.8;
  border-top: 1px dashed var(--border-color);
  margin-top: 0.5rem;
  padding-top: 1rem;
}

/* ==================================================
   文章页面规范 (Article Pages)
================================================== */
.article-header {
  padding: 2.5rem 0 1.75rem;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-white);
}

.breadcrumb-nav {
  font-size: 0.8125rem;
  color: var(--text-sub);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.4rem;
}

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

.breadcrumb-separator {
  color: var(--text-sub);
}

.article-title {
  font-size: clamp(1.8rem, 3.2vw, 2.6rem);
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.3;
  margin-bottom: 1rem;
}

.article-summary-lead {
  font-size: 1.1rem;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 1.25rem;
}

.article-meta-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.25rem;
  font-size: 0.8125rem;
  color: var(--text-sub);
}

/* GEO 快速结论框 (Quick Conclusion Alert) */
.geo-conclusion-box {
  background-color: var(--color-tag-green);
  border: 1px solid var(--color-accent);
  border-left: 4px solid var(--color-accent);
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
  border-radius: 2px;
}

.geo-title {
  font-size: 0.9rem;
  font-weight: 800;
  color: var(--color-accent);
  margin-bottom: 0.4rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.geo-text {
  font-size: 0.95rem;
  color: var(--text-main);
  margin-bottom: 0;
  line-height: 1.75;
}

/* 文章目录 */
.toc-box {
  background-color: var(--bg-alt);
  border: 1px solid var(--border-color);
  padding: 1.25rem 1.5rem;
  margin-bottom: 2.5rem;
  border-radius: 2px;
}

.toc-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 0.75rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border-color);
}

.toc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  font-size: 0.875rem;
}

.toc-list a {
  color: var(--color-primary);
  display: block;
  padding: 0.15rem 0;
}

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

/* 正文样式 */
.article-content {
  padding: 2.5rem 0;
  font-size: 1.05rem;
  line-height: 1.9;
  color: var(--text-main);
}

.article-content h2 {
  margin-top: 2.75rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
}

.article-content h3 {
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
}

.article-content ul,
.article-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.article-content li {
  margin-bottom: 0.5rem;
}

/* 文章底部关联导航与返回 */
.article-footer-nav {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.related-reading-box {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  padding: 1.5rem;
  margin-bottom: 2rem;
  border-radius: 2px;
}

.related-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 1rem;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

.related-item {
  border-left: 2px solid var(--color-primary);
  padding-left: 0.75rem;
}

.prev-next-bar {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

/* ==================================================
   分类页规范 (Category Pages)
================================================== */
.category-header {
  padding: 2.5rem 0 2rem;
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
}

.category-intro-box {
  background-color: var(--bg-alt);
  border: 1px solid var(--border-color);
  padding: 1.25rem 1.5rem;
  margin-top: 1rem;
  border-radius: 2px;
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.8;
}

.category-article-list {
  padding: 2.5rem 0;
}

/* ==================================================
   页脚 Footer (浅冷灰 #EBEFEF, 文字 #465159)
================================================== */
.site-footer {
  background-color: var(--bg-footer);
  color: var(--text-footer);
  border-top: 1px solid var(--border-color);
  padding: 3rem 0 1.5rem;
  font-size: 0.875rem;
}

.footer-top-grid {
  display: grid;
  grid-template-columns: 2fr 1.2fr 1.2fr 1.2fr 1.2fr;
  gap: 2rem;
  margin-bottom: 2.5rem;
}

.footer-brand-col {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.footer-brand-title {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text-main);
}

.footer-brand-desc {
  font-size: 0.8125rem;
  color: var(--text-footer);
  line-height: 1.7;
}

.footer-col-title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 0.85rem;
  letter-spacing: 0.02em;
}

.footer-link-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-link-list a {
  color: var(--text-footer);
  transition: color var(--transition-fast);
}

.footer-link-list a:hover {
  color: var(--color-primary-dark);
}

/* 页脚最底部行 (严格固定) */
.footer-bottom-bar {
  border-top: 1px solid #D8DFE0;
  padding-top: 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.8125rem;
}

.footer-copyright {
  color: var(--text-footer);
}

.footer-friend-links {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.85rem;
}

.friend-label {
  font-weight: 700;
  color: var(--text-main);
}

.footer-friend-links a {
  color: var(--text-footer);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

/* ==================================================
   响应式断点适配 (1024, 768, 430, 390, 375)
================================================== */
@media (max-width: 1024px) {
  .desktop-nav {
    display: none;
  }
  
  .mobile-menu-btn {
    display: inline-block;
  }
  
  .footer-top-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .troubleshoot-steps {
    grid-template-columns: repeat(4, 1fr);
  }
  
  .axis-track {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }
  
  .axis-track::before {
    display: none;
  }
  
  .axis-node {
    flex-direction: row;
    text-align: left;
    gap: 1rem;
  }
  
  .node-dot {
    margin-bottom: 0;
    flex-shrink: 0;
  }
  
  /* 隐藏桌面端方案矩阵，显示移动端专用参数列表 */
  .plans-matrix-container {
    display: none;
  }
  
  .mobile-plans-list {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
  }
  
  .mobile-plan-card {
    background-color: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: 2px;
    padding: 1.25rem;
  }
  
  .mobile-plan-card.featured {
    border-top: 4px solid var(--color-accent);
    background-color: var(--color-tag-green);
  }
  
  .mobile-plan-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 0.75rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
  }
  
  .mobile-plan-param-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem;
    font-size: 0.85rem;
    margin-bottom: 1rem;
  }
  
  .param-item {
    display: flex;
    flex-direction: column;
  }
  
  .param-k {
    font-size: 0.75rem;
    color: var(--text-sub);
  }
  
  .param-v {
    font-weight: 700;
    color: var(--text-main);
  }
  
  /* 隐藏桌面端 5x4 Hero 矩阵，显示用途分组折叠/卡片 */
  .hero-matrix-wrapper {
    display: none;
  }
  
  .hero-matrix-mobile {
    display: flex;
    flex-direction: column;
    gap: 0.85rem;
  }
  
  .mobile-matrix-group {
    background-color: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: 2px;
    padding: 0.85rem 1rem;
  }
  
  .mobile-group-title {
    font-size: 0.9rem;
    font-weight: 800;
    color: var(--color-primary);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
  }
  
  .mobile-tier-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.85rem;
    padding: 0.35rem 0;
    border-bottom: 1px dashed var(--border-color);
  }
  
  .mobile-tier-row:last-child {
    border-bottom: none;
  }
  
  .footer-top-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
  
  .footer-bottom-bar {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 430px) {
  .troubleshoot-steps {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .hero-headline {
    font-size: 1.85rem;
  }
  
  .btn-cta {
    width: 100%;
  }
  
  .backup-info-group {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
}

/* ==================================================
   prefers-reduced-motion 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;
  }
  
  .btn-cta:hover .btn-arrow {
    transform: none !important;
  }
}