/* ==================================================
   悠兔机场 (YouTu Cloud) - 平衡编排系统 (V3)
   成熟商务 · 一主多辅 · 非对称平衡 · 纯净高性能
   ================================================== */

:root {
  /* 品牌色系规范 */
  --bg-main: #FBFAF7;
  --bg-card: #FFFFFF;
  --bg-secondary: #F3F1EC;
  --bg-footer: #F1F0EB;
  
  --text-main: #1F2527;
  --text-body: #5A6366;
  --text-muted: #858D90;
  
  --blue-grey: #465E69;
  --blue-grey-dark: #354A53;
  --green-grey: #5F7067;
  --green-grey-dark: #4B5B53;
  
  --copper: #AA7955;
  --terracotta: #B06D50;
  
  --light-green: #EFF2EF;
  --light-blue: #EEF1F2;
  --light-warm: #F6EFE7;
  
  --border: #E0DED8;
  --border-subtle: #ECEAE4;
  --border-focus: #AA7955;
  
  --shadow-subtle: 0 10px 28px rgba(31, 37, 39, 0.03);
  --shadow-hover: 0 12px 32px rgba(31, 37, 39, 0.06);

  /* 字体族 */
  --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  
  /* 尺寸与间距 */
  --max-width: 1240px;
  --header-height: 70px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 10px;
  
  --transition-fast: 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-normal: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

/* 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-stack);
  background-color: var(--bg-main);
  color: var(--text-main);
  line-height: 1.8;
  font-size: 1rem;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

img, svg {
  display: block;
  max-width: 100%;
}

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

ul, ol {
  list-style: none;
}

/* 辅助与无障碍 */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* 容器定义 */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* 标签与徽章 */
.section-tag {
  display: inline-block;
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--blue-grey);
  margin-bottom: 12px;
  text-transform: uppercase;
}

.badge-priority {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--copper);
  background-color: var(--light-warm);
  border: 1px solid rgba(170, 121, 85, 0.3);
  border-radius: var(--radius-sm);
  margin-left: 8px;
}

.badge-tag {
  display: inline-block;
  font-size: 0.75rem;
  padding: 2px 7px;
  border-radius: var(--radius-sm);
  background-color: var(--light-blue);
  color: var(--blue-grey-dark);
  border: 1px solid var(--border);
}

/* 排版规范 */
h1, h2, h3, h4 {
  color: var(--text-main);
  font-weight: 600;
  line-height: 1.35;
}

h1 {
  font-size: 2.75rem; /* 44px */
  letter-spacing: -0.02em;
}

h2 {
  font-size: 1.875rem; /* 30px */
  letter-spacing: -0.01em;
  margin-bottom: 16px;
}

h3 {
  font-size: 1.375rem; /* 22px */
  margin-bottom: 10px;
}

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

.section-lead {
  font-size: 1.125rem;
  color: var(--text-body);
  margin-bottom: 32px;
  max-width: 820px;
}

/* 按钮规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 11px 22px;
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn-primary {
  background-color: var(--blue-grey-dark);
  color: #FFFFFF;
  border: 1px solid var(--blue-grey-dark);
}

.btn-primary:hover {
  background-color: #26363d;
  color: #FFFFFF;
  transform: translateY(-1px);
}

.btn-copper {
  background-color: var(--copper);
  color: #FFFFFF;
  border: 1px solid var(--copper);
}

.btn-copper:hover {
  background-color: var(--terracotta);
  color: #FFFFFF;
  transform: translateY(-1px);
}

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

.btn-outline:hover {
  border-color: var(--blue-grey);
  color: var(--blue-grey-dark);
  background-color: var(--light-blue);
}

.btn-text {
  display: inline-flex;
  align-items: center;
  color: var(--copper);
  font-weight: 500;
  font-size: 0.9375rem;
  padding: 4px 0;
  border-bottom: 1px solid transparent;
}

.btn-text .arrow {
  margin-left: 6px;
  transition: transform var(--transition-fast);
}

.btn-text:hover {
  color: var(--terracotta);
  border-bottom-color: var(--terracotta);
}

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

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

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

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

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

.brand-meta {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-main);
  line-height: 1.2;
}

.brand-subline {
  font-size: 0.75rem;
  color: var(--text-muted);
  line-height: 1.2;
  margin-top: 2px;
}

.nav-desktop {
  display: flex;
  align-items: center;
  gap: 22px;
}

.nav-link {
  font-size: 0.9375rem;
  color: var(--text-body);
  position: relative;
  padding: 6px 0;
  font-weight: 400;
}

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

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

.nav-link.active::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -4px;
  height: 2px;
  background-color: var(--blue-grey-dark);
}

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

.menu-toggle-btn {
  display: none;
  padding: 8px 12px;
  font-size: 0.9375rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-main);
  background: var(--bg-card);
}

/* 移动端菜单抽屉 */
.mobile-nav-panel {
  display: none;
  background-color: var(--bg-main);
  border-bottom: 1px solid var(--border);
  padding: 20px 24px;
}

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

.mobile-nav-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 20px;
}

.mobile-nav-item a {
  font-size: 1.0625rem;
  color: var(--text-main);
  display: block;
  padding: 8px 0;
  border-bottom: 1px solid var(--border-subtle);
}

.mobile-nav-item a.active {
  color: var(--blue-grey-dark);
  font-weight: 600;
}

/* ==================================================
   Hero 平衡编排系统 (Asymmetric Balance)
   ================================================== */
.hero-section {
  padding-top: 40px;
  padding-bottom: 48px;
}

.hero-balance-canvas {
  display: grid;
  grid-template-columns: 1.25fr 0.95fr;
  grid-template-rows: auto auto;
  gap: 20px;
}

/* Hero 主品牌区 (~50% 重量) */
.hero-primary-block {
  grid-column: 1 / 2;
  grid-row: 1 / 2;
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 44px 40px;
  box-shadow: var(--shadow-subtle);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.hero-tag {
  display: inline-block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--copper);
  letter-spacing: 0.05em;
  margin-bottom: 16px;
}

.hero-main-title {
  font-size: 2.25rem;
  line-height: 1.3;
  margin-bottom: 16px;
  color: var(--text-main);
  font-weight: 600;
}

.hero-h1-statement {
  font-size: 1.25rem;
  color: var(--blue-grey-dark);
  font-weight: 600;
  margin-bottom: 18px;
  line-height: 1.45;
  border-left: 3px solid var(--blue-grey);
  padding-left: 14px;
}

.hero-intro-text {
  font-size: 1.0625rem;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 32px;
}

.hero-actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
}

/* Hero 辅区01 & 02 容器 */
.hero-aux-col {
  grid-column: 2 / 3;
  grid-row: 1 / 2;
  display: grid;
  grid-template-rows: 1fr 1fr;
  gap: 20px;
}

.hero-aux-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 26px 28px;
  box-shadow: var(--shadow-subtle);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.hero-aux-card:hover {
  transform: translateY(-2px);
  border-color: var(--blue-grey);
}

.aux-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}

.aux-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-main);
}

.aux-badge {
  font-size: 0.75rem;
  padding: 2px 6px;
  background-color: var(--light-warm);
  color: var(--copper);
  border-radius: var(--radius-sm);
  font-weight: 500;
}

.aux-content-lead {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 6px;
}

.aux-content-lead span {
  font-size: 0.9375rem;
  color: var(--text-muted);
  font-weight: 400;
}

.aux-desc {
  font-size: 0.9375rem;
  color: var(--text-body);
  margin-bottom: 16px;
  line-height: 1.6;
}

.aux-chip-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.chip-item {
  font-size: 0.8125rem;
  padding: 3px 10px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-main);
}

/* Hero 横向平衡补充区 (30% 跨底辅助) */
.hero-horizontal-bar {
  grid-column: 1 / 3;
  grid-row: 2 / 3;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px 32px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.hero-bar-item {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.bar-item-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.bar-item-title {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-main);
}

.bar-item-tokens {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.token-pill {
  font-size: 0.8125rem;
  color: var(--blue-grey-dark);
  background-color: #FFFFFF;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

/* ==================================================
   主次模块网格通用规范 (一主多辅)
   ================================================== */
.section-wrapper {
  padding-top: 64px;
  padding-bottom: 64px;
  border-top: 1px solid var(--border-subtle);
}

.section-head {
  margin-bottom: 36px;
}

/* 一主四辅布局 (套餐与需求) */
.balance-grid-1-4 {
  display: grid;
  grid-template-columns: 1.35fr 1fr;
  gap: 24px;
  align-items: stretch;
}

.primary-plan-panel {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 38px 36px;
  box-shadow: var(--shadow-subtle);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.plan-head-tag {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.plan-price-hero {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin-bottom: 14px;
}

.plan-price-val {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1;
}

.plan-price-period {
  font-size: 1.125rem;
  color: var(--text-muted);
}

.plan-traffic-pill {
  display: inline-block;
  background-color: var(--light-warm);
  color: var(--copper);
  font-weight: 600;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  margin-bottom: 20px;
  font-size: 1rem;
}

.plan-points-list {
  margin-top: 20px;
  margin-bottom: 32px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.plan-point-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.9375rem;
  color: var(--text-body);
}

.plan-point-item::before {
  content: "—";
  color: var(--copper);
  font-weight: 700;
}

/* 辅区 2x2 共享分隔线面板 */
.aux-grid-2x2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 1fr 1fr;
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-subtle);
  overflow: hidden;
}

.aux-demand-cell {
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
  border-right: 1px solid var(--border);
  transition: background-color var(--transition-fast);
}

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

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

.aux-demand-cell:hover {
  background-color: var(--bg-main);
}

.cell-title-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.cell-title {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-main);
}

.cell-desc {
  font-size: 0.875rem;
  color: var(--text-body);
  line-height: 1.6;
  margin-bottom: 14px;
}

/* 一主三辅网格 (线路、节点、网络排障等) */
.balance-grid-1-3 {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 24px;
}

.main-column-panel {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 36px 34px;
  box-shadow: var(--shadow-subtle);
}

.side-aux-stack {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.aux-box {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 22px 24px;
  box-shadow: var(--shadow-subtle);
  transition: border-color var(--transition-fast), transform var(--transition-fast);
}

.aux-box:hover {
  border-color: var(--blue-grey);
  transform: translateY(-2px);
}

.aux-box-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.aux-box-title {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-main);
}

/* 一主二辅网格 (AI、流媒体、客户端、动态倍率等) */
.balance-grid-1-2 {
  display: grid;
  grid-template-columns: 1.25fr 1fr;
  gap: 24px;
}

.side-aux-double {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* ==================================================
   精简表格规范 (横线、高留白、非Excel)
   ================================================== */
.tech-table-container {
  margin-top: 32px;
  overflow-x: auto;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  background: var(--bg-card);
}

.tech-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9375rem;
}

.tech-table th {
  padding: 16px 20px;
  font-weight: 600;
  color: var(--blue-grey-dark);
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}

.tech-table td {
  padding: 18px 20px;
  color: var(--text-body);
  border-bottom: 1px solid var(--border-subtle);
  line-height: 1.7;
}

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

.tech-table tr:hover td {
  background-color: var(--bg-main);
}

.table-tech-name {
  font-weight: 600;
  color: var(--text-main);
  white-space: nowrap;
}

/* ==================================================
   评测与教程模块
   ================================================== */
.review-highlight-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 36px 36px;
  box-shadow: var(--shadow-subtle);
  margin-bottom: 24px;
}

.quick-conclusion-box {
  background-color: var(--light-green);
  border-left: 4px solid var(--green-grey);
  padding: 18px 22px;
  border-radius: var(--radius-sm);
  margin-top: 20px;
  margin-bottom: 24px;
}

.quick-conclusion-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--green-grey-dark);
  margin-bottom: 6px;
}

.quick-conclusion-text {
  font-size: 0.9375rem;
  color: var(--text-main);
  line-height: 1.75;
}

/* 教程专题展示目录 */
.tutorial-layout {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 24px;
}

.featured-tutorial-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 32px 30px;
  box-shadow: var(--shadow-subtle);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.tutorial-topic-col {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.topic-group-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px 22px;
  box-shadow: var(--shadow-subtle);
}

.topic-group-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--blue-grey-dark);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.topic-link-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.topic-link-item a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.9375rem;
  color: var(--text-body);
  padding: 6px 0;
  border-bottom: 1px dashed var(--border-subtle);
}

.topic-link-item a:hover {
  color: var(--copper);
}

/* ==================================================
   常见问题 FAQ 折叠栏
   ================================================== */
.faq-groups-wrap {
  display: flex;
  flex-direction: column;
  gap: 36px;
}

.faq-group-box {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-subtle);
  padding: 28px 32px;
}

.faq-group-header {
  font-size: 1.1875rem;
  font-weight: 600;
  color: var(--blue-grey-dark);
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--light-blue);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

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

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

.faq-summary {
  list-style: none;
  cursor: pointer;
  padding: 16px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 1.0625rem;
  font-weight: 500;
  color: var(--text-main);
  user-select: none;
}

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

.faq-q-num {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--blue-grey);
  margin-right: 12px;
}

.faq-q-text {
  flex-grow: 1;
}

.faq-icon-toggle {
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--text-muted);
  transition: transform var(--transition-fast);
  margin-left: 12px;
}

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

.faq-answer {
  padding-bottom: 18px;
  padding-left: 36px;
  color: var(--text-body);
  font-size: 0.9688rem;
  line-height: 1.8;
}

/* ==================================================
   Footer 底部规范 (浅暖灰绿, 紧凑 250-320px)
   ================================================== */
.site-footer {
  background-color: var(--bg-footer);
  border-top: 1px solid var(--border);
  padding-top: 48px;
  padding-bottom: 32px;
  color: #4A5457;
  font-size: 0.875rem;
}

.footer-nav-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr 1fr;
  gap: 32px;
  margin-bottom: 40px;
}

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

.footer-brand-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 6px;
}

.footer-brand-desc {
  font-size: 0.875rem;
  color: #6C777A;
  line-height: 1.6;
  margin-bottom: 16px;
}

.footer-col-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 14px;
}

.footer-links-list {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.footer-links-list a {
  color: #556164;
  transition: color var(--transition-fast);
}

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

.footer-bottom-bar {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.8125rem;
  color: #727D80;
}

.friend-links-wrap {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.friend-links-wrap a {
  color: #556164;
}

.friend-links-wrap a:hover {
  color: var(--copper);
}

/* ==================================================
   文章页面规范 (Article Pages)
   ================================================== */
.article-header {
  padding-top: 36px;
  padding-bottom: 24px;
}

.breadcrumb-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

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

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

.breadcrumb-sep {
  color: var(--text-muted);
}

.article-hero-box {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 40px;
  box-shadow: var(--shadow-subtle);
  margin-bottom: 32px;
}

.article-meta-row {
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
  font-size: 0.8438rem;
  color: var(--text-muted);
  margin-top: 14px;
  margin-bottom: 20px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border-subtle);
}

.article-meta-row span {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.article-summary-lead {
  font-size: 1.125rem;
  color: var(--text-body);
  line-height: 1.85;
}

/* 文章主体分栏：正文 (760-820px) + 右侧轻量目录 (~220px) */
.article-content-layout {
  display: grid;
  grid-template-columns: minmax(0, 820px) 240px;
  gap: 40px;
  align-items: start;
  padding-bottom: 64px;
}

.article-body {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 44px 48px;
  box-shadow: var(--shadow-subtle);
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--text-body);
}

.article-body h2 {
  font-size: 1.625rem;
  color: var(--text-main);
  margin-top: 40px;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-subtle);
}

.article-body h2:first-of-type {
  margin-top: 0;
}

.article-body h3 {
  font-size: 1.25rem;
  color: var(--text-main);
  margin-top: 28px;
  margin-bottom: 12px;
}

.article-body p {
  margin-bottom: 20px;
}

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

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

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

.article-body li {
  margin-bottom: 8px;
}

.article-body blockquote {
  border-left: 3px solid var(--blue-grey);
  padding: 14px 20px;
  background-color: var(--bg-secondary);
  margin: 24px 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-main);
}

/* 侧边目录 */
.article-toc-aside {
  position: sticky;
  top: 90px;
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--shadow-subtle);
}

.toc-heading {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--blue-grey-dark);
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-subtle);
}

.toc-nav-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-height: 70vh;
  overflow-y: auto;
}

.toc-nav-link {
  font-size: 0.8438rem;
  color: var(--text-body);
  line-height: 1.4;
  padding: 4px 0;
  transition: color var(--transition-fast);
}

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

/* 内链闭环与推荐阅读 */
.article-footer-nav {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}

.related-articles-box {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  margin-top: 24px;
}

.related-articles-title {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 14px;
}

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

.related-item a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9375rem;
  color: var(--blue-grey-dark);
}

.related-item a:hover {
  color: var(--copper);
  text-decoration: underline;
}

/* ==================================================
   分类页面规范 (Category Pages)
   ================================================== */
.category-hero {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 38px 40px;
  margin-bottom: 36px;
  box-shadow: var(--shadow-subtle);
}

.category-article-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-bottom: 48px;
}

.category-article-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 26px 30px;
  box-shadow: var(--shadow-subtle);
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.category-article-card:hover {
  transform: translateY(-2px);
  border-color: var(--blue-grey);
}

.cat-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}

.cat-card-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-main);
}

.cat-card-title a:hover {
  color: var(--copper);
}

.cat-card-excerpt {
  font-size: 0.9688rem;
  color: var(--text-body);
  margin-bottom: 14px;
  line-height: 1.7;
}

/* 404 与 Legal 页面规范 */
.legal-page-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 44px 48px;
  margin: 40px auto;
  max-width: 880px;
  box-shadow: var(--shadow-subtle);
}

.legal-page-card h1 {
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}

.notfound-container {
  text-align: center;
  padding: 80px 24px;
  max-width: 640px;
  margin: 0 auto;
}

.notfound-code {
  font-size: 4.5rem;
  font-weight: 700;
  color: var(--copper);
  line-height: 1;
  margin-bottom: 12px;
}

/* ==================================================
   响应式断点适配 (1024px, 768px, 430px, 390px, 375px)
   ================================================== */
@media (max-width: 1024px) {
  .hero-balance-canvas {
    grid-template-columns: 1fr;
  }
  
  .hero-aux-col {
    grid-column: 1 / 2;
    grid-template-columns: 1fr 1fr;
    grid-template-rows: auto;
  }
  
  .hero-horizontal-bar {
    grid-column: 1 / 2;
  }
  
  .balance-grid-1-4,
  .balance-grid-1-3,
  .balance-grid-1-2,
  .tutorial-layout {
    grid-template-columns: 1fr;
  }
  
  .article-content-layout {
    grid-template-columns: 1fr;
  }
  
  .article-toc-aside {
    display: none; /* 移动端可隐藏或改为折叠，正文先行 */
  }
  
  .footer-nav-grid {
    grid-template-columns: 1fr 1fr 1fr;
  }
  
  .footer-brand-col {
    grid-column: 1 / -1;
  }
}

@media (max-width: 768px) {
  .nav-desktop {
    display: none;
  }
  
  .menu-toggle-btn {
    display: block;
  }
  
  .hero-primary-block {
    padding: 30px 24px;
  }
  
  .hero-main-title {
    font-size: 1.75rem;
  }
  
  .hero-h1-statement {
    font-size: 1.125rem;
  }
  
  .hero-aux-col {
    grid-template-columns: 1fr;
  }
  
  .hero-horizontal-bar {
    grid-template-columns: 1fr;
    padding: 20px 24px;
    gap: 20px;
  }
  
  .aux-grid-2x2 {
    grid-template-columns: 1fr;
    grid-template-rows: auto;
  }
  
  .aux-demand-cell {
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  
  .aux-demand-cell:last-child {
    border-bottom: none;
  }
  
  .primary-plan-panel {
    padding: 28px 24px;
  }
  
  .main-column-panel {
    padding: 28px 24px;
  }
  
  .article-body {
    padding: 28px 20px;
  }
  
  .article-hero-box {
    padding: 28px 20px;
  }
  
  .footer-nav-grid {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }
  
  .footer-bottom-bar {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 430px) {
  .container {
    padding-left: 16px;
    padding-right: 16px;
  }
  
  .hero-main-title {
    font-size: 1.5rem;
  }
  
  .plan-price-val {
    font-size: 2.125rem;
  }
  
  .footer-nav-grid {
    grid-template-columns: 1fr;
  }
  
  .header-cta-wrap .btn-primary {
    display: none; /* 移动端顶部保留菜单入口，避免空间挤压 */
  }
}

/* ==================================================
   减少动画适配 (prefers-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;
  }
}