/* ===================================================================
   冲上云霄云机场 (chongshangyunxiao.sbs) 官方样式库
   主题：破界遨游 · 霄汉穿梭 (Modern Crisp White & Ocean Blue Theme 清新白蓝科技风)
   设计风格：清新白蓝渐变背景 + 晶莹白玉卡片 + 蔚蓝流光按钮 + 移动端极致响应
   =================================================================== */

:root {
  --primary: #0284c7;
  --primary-light: rgba(2, 132, 199, 0.08);
  --primary-grad: linear-gradient(135deg, #0284c7 0%, #2563eb 50%, #3b82f6 100%);
  --primary-hover: linear-gradient(135deg, #0369a1 0%, #1d4ed8 50%, #2563eb 100%);
  --blue-grad: linear-gradient(135deg, #0284c7 0%, #3b82f6 100%);
  --cyan-grad: linear-gradient(135deg, #06b6d4 0%, #0284c7 100%);
  --amber-grad: linear-gradient(135deg, #f59e0b 0%, #ef4444 100%);

  --bg-page: #f8fafc;
  --bg-page-alt: #f0f7ff;
  --bg-card: rgba(255, 255, 255, 0.94);
  --bg-card-hover: rgba(240, 249, 255, 0.98);
  --bg-soft: rgba(224, 242, 254, 0.55);
  --bg-item: rgba(241, 245, 249, 0.85);

  --accent-purple: #6366f1;
  --accent-indigo: #4f46e5;
  --accent-cyan: #0284c7;
  --accent-teal: #0d9488;
  --accent-amber: #f59e0b;
  --accent-pink: #ec4899;

  --text-heading: #0f172a;
  --text-main: #1e293b;
  --text-body: #334155;
  --text-muted: #64748b;
  --text-dimmer: #94a3b8;

  --border-light: rgba(226, 232, 240, 0.9);
  --border-accent: rgba(2, 132, 199, 0.35);
  --border-subtle: rgba(226, 232, 240, 0.7);
  --border-bright: rgba(2, 132, 199, 0.65);

  --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.04);
  --shadow-card: 0 10px 28px -6px rgba(15, 23, 42, 0.07), 0 0 1px rgba(15, 23, 42, 0.06);
  --shadow-hover: 0 16px 36px -8px rgba(2, 132, 199, 0.18), 0 0 20px rgba(2, 132, 199, 0.1);
  --shadow-btn: 0 6px 20px rgba(2, 132, 199, 0.28);
  --shadow-glow: 0 0 28px rgba(2, 132, 199, 0.2);

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 8px;
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-page);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.65;
}

body {
  overflow-x: hidden;
  position: relative;
  min-height: 100vh;
  background-color: #f8fafc;
  background: 
    radial-gradient(circle at 15% 10%, rgba(186, 230, 253, 0.5) 0%, transparent 45%),
    radial-gradient(circle at 85% 20%, rgba(199, 210, 254, 0.4) 0%, transparent 50%),
    radial-gradient(circle at 50% 75%, rgba(224, 242, 254, 0.5) 0%, transparent 60%),
    #f8fafc;
  background-attachment: fixed;
  color: var(--text-body);
}

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition-smooth);
}

ul, ol {
  list-style: none;
}

img, svg {
  vertical-align: middle;
  max-width: 100%;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 文字渐变与标签 */
.text-gradient {
  background: var(--primary-grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

.badge-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  border-radius: 999px;
  font-size: 0.86rem;
  font-weight: 700;
  background: rgba(2, 132, 199, 0.08);
  border: 1px solid var(--border-accent);
  color: #0284c7;
  box-shadow: 0 0 16px rgba(2, 132, 199, 0.1);
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #0284c7;
  box-shadow: 0 0 10px #0284c7;
  animation: pulseAnim 2s infinite;
}

@keyframes pulseAnim {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

/* 按钮规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: 0.96rem;
  font-weight: 700;
  border-radius: 30px;
  cursor: pointer;
  border: none;
  outline: none;
  transition: var(--transition-smooth);
  text-align: center;
}

.btn-primary {
  background: var(--primary-grad);
  color: #ffffff !important;
  box-shadow: var(--shadow-btn);
}

.btn-primary:hover {
  background: var(--primary-hover);
  color: #ffffff !important;
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(2, 132, 199, 0.45);
}

.btn-secondary {
  background: #ffffff;
  color: #0284c7;
  border: 1px solid var(--border-bright);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(12px);
}

.btn-secondary:hover {
  background: #f0f9ff;
  border-color: #0284c7;
  color: #0369a1;
  transform: translateY(-2px);
  box-shadow: 0 0 20px rgba(2, 132, 199, 0.2);
}

.btn-lg {
  padding: 15px 36px;
  font-size: 1.05rem;
}

/* 卡片基类 */
.glass-panel {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: var(--transition-smooth);
}

.glass-panel:hover {
  border-color: var(--border-accent);
  box-shadow: var(--shadow-hover);
  transform: translateY(-3px);
}

/* 章节通用标题区 */
.section-padding {
  padding: 85px 0;
}

.section-header {
  text-align: center;
  max-width: 780px;
  margin: 0 auto 50px;
}

.section-tag {
  display: inline-block;
  font-size: 0.84rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.8px;
  color: #0284c7;
  margin-bottom: 10px;
}

.section-title {
  font-size: 2.3rem;
  font-weight: 900;
  line-height: 1.25;
  margin-bottom: 16px;
  color: var(--text-heading);
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.75;
}

/* -------------------------------------------------------------
   头部导航栏 (Floating Navigation Dock)
   ------------------------------------------------------------- */
.header-nav {
  position: sticky;
  top: 0;
  z-index: 999;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-light);
  box-shadow: 0 4px 20px rgba(15, 23, 42, 0.05);
  transition: var(--transition-smooth);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 74px;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.3rem;
  font-weight: 900;
  color: var(--text-heading);
}

.brand-logo img {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  box-shadow: 0 0 16px rgba(2, 132, 199, 0.25);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-body);
  position: relative;
  padding: 6px 0;
}

.nav-link:hover {
  color: #0284c7;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background: var(--primary-grad);
  transition: width 0.3s ease;
  border-radius: 2px;
}

.nav-link:hover::after {
  width: 100%;
}

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

.mobile-toggle {
  display: none;
  background: transparent;
  border: none;
  color: var(--text-heading);
  font-size: 1.6rem;
  cursor: pointer;
}

/* -------------------------------------------------------------
   Hero 核心首屏
   ------------------------------------------------------------- */
.hero-section {
  padding: 70px 0 60px;
  position: relative;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 50px;
  align-items: center;
}

.hero-title {
  font-size: 3.2rem;
  font-weight: 900;
  line-height: 1.2;
  margin: 22px 0 20px;
  color: var(--text-heading);
  letter-spacing: -0.5px;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-body);
  line-height: 1.85;
  margin-bottom: 34px;
}

.hero-cta-box {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

.hero-stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  padding-top: 24px;
  border-top: 1px solid var(--border-subtle);
}

.stat-item h4 {
  font-size: 1.75rem;
  font-weight: 900;
  color: #0284c7;
  margin-bottom: 4px;
  text-shadow: 0 0 12px rgba(2, 132, 199, 0.25);
}

.stat-item p {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* -------------------------------------------------------------
   Hero 右侧全新模式：全场景专线拓扑中枢与控制台 (Transit Topology Console)
   ------------------------------------------------------------- */
.hero-transit-console {
  padding: 26px;
  background: rgba(255, 255, 255, 0.94);
  border: 1px solid rgba(2, 132, 199, 0.22);
  border-radius: var(--radius-lg);
  box-shadow: 0 16px 40px -10px rgba(15, 23, 42, 0.08), 0 0 30px rgba(2, 132, 199, 0.12);
  position: relative;
  overflow: hidden;
}

.hero-transit-console::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, #0284c7, #38bdf8, #2563eb, transparent);
}

.console-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border-subtle);
}

.console-title {
  display: flex;
  align-items: center;
  gap: 12px;
}

.console-icon {
  font-size: 1.4rem;
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(2, 132, 199, 0.08);
  border: 1px solid rgba(2, 132, 199, 0.25);
  border-radius: 10px;
}

.console-main-name {
  font-size: 0.98rem;
  font-weight: 800;
  color: var(--text-heading);
  letter-spacing: 0.2px;
}

.console-sub-name {
  font-size: 0.72rem;
  color: var(--text-dimmer);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 5px 12px;
  border-radius: 999px;
  font-size: 0.76rem;
  font-weight: 700;
  background: rgba(34, 197, 94, 0.12);
  color: #16a34a;
  border: 1px solid rgba(34, 197, 94, 0.3);
  box-shadow: 0 0 12px rgba(34, 197, 94, 0.15);
}

/* 智能分流路线图 (Workflow Route Card) */
.workflow-route-card {
  background: rgba(240, 249, 255, 0.9);
  border: 1px solid rgba(2, 132, 199, 0.2);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  margin-bottom: 18px;
}

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

.wf-title {
  font-size: 0.82rem;
  font-weight: 700;
  color: #0284c7;
  display: flex;
  align-items: center;
  gap: 6px;
}

.wf-badge {
  font-size: 0.7rem;
  color: #0284c7;
  background: rgba(2, 132, 199, 0.1);
  padding: 2px 8px;
  border-radius: 4px;
  border: 1px solid rgba(2, 132, 199, 0.25);
}

.workflow-pipeline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
}

.pipe-node {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 8px 6px;
  background: #ffffff;
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  transition: var(--transition-smooth);
}

.pipe-node.active-pipe {
  background: rgba(2, 132, 199, 0.08);
  border-color: rgba(2, 132, 199, 0.45);
  box-shadow: 0 0 16px rgba(2, 132, 199, 0.15);
}

.pipe-icon {
  font-size: 1.15rem;
  margin-bottom: 3px;
}

.p-title {
  font-size: 0.78rem;
  font-weight: 800;
  color: var(--text-heading);
  display: block;
}

.p-desc {
  font-size: 0.68rem;
  color: var(--text-muted);
  display: block;
  margin-top: 1px;
}

.pipe-connector {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  min-width: 32px;
}

.pipe-line {
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, rgba(2, 132, 199, 0.3), rgba(37, 99, 235, 0.8), rgba(2, 132, 199, 0.3));
  border-radius: 2px;
  position: relative;
}

.pipe-speed {
  font-size: 0.64rem;
  font-weight: 700;
  color: #0284c7;
}

/* 4 大骨干专线节点卡片列表 */
.console-nodes-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 18px;
}

.console-node-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  background: #ffffff;
  border: 1px solid rgba(226, 232, 240, 0.9);
  border-radius: var(--radius-sm);
  transition: var(--transition-smooth);
}

.console-node-card:hover {
  background: #f0f9ff;
  border-color: rgba(2, 132, 199, 0.4);
  transform: translateX(3px);
}

.c-node-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.c-flag {
  font-size: 1.35rem;
}

.c-node-name {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text-heading);
}

.c-node-tag {
  font-size: 0.74rem;
  color: var(--text-muted);
  margin-top: 1px;
}

.c-node-right {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 3px;
}

.ping-val {
  font-size: 0.84rem;
  font-weight: 800;
  color: #0284c7;
  font-family: monospace;
}

.c-node-status {
  font-size: 0.68rem;
  color: #16a34a;
  background: rgba(34, 197, 94, 0.1);
  padding: 1px 6px;
  border-radius: 3px;
}

/* 底部交互区 */
.console-footer {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.console-test-btn {
  width: 100%;
  padding: 10px 20px;
  font-size: 0.88rem;
  font-weight: 700;
  text-align: center;
  border-radius: var(--radius-sm);
}

.supported-protocol-pills {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px;
}

.proto-tag {
  font-size: 0.72rem;
  font-weight: 600;
  color: #0284c7;
  background: rgba(2, 132, 199, 0.08);
  border: 1px solid rgba(2, 132, 199, 0.2);
  padding: 3px 9px;
  border-radius: 999px;
  letter-spacing: 0.3px;
}

/* -------------------------------------------------------------
   核心优势 Bento 网格 (Core Advantages)
   ------------------------------------------------------------- */
.bento-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.bento-card {
  padding: 36px 30px;
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
}

.bento-card.span-2 {
  grid-column: span 2;
}

.bento-icon {
  font-size: 2.2rem;
  margin-bottom: 20px;
  display: inline-block;
  padding: 12px 14px;
  border-radius: var(--radius-md);
  background: rgba(2, 132, 199, 0.08);
  border: 1px solid rgba(2, 132, 199, 0.25);
  box-shadow: 0 0 16px rgba(2, 132, 199, 0.1);
}

.bento-card h3 {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-heading);
  margin-bottom: 12px;
  line-height: 1.35;
}

.bento-card p {
  font-size: 0.96rem;
  color: var(--text-body);
  line-height: 1.75;
}

/* -------------------------------------------------------------
   套餐价格矩阵 (Pricing Section)
   ------------------------------------------------------------- */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  padding: 36px 26px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
}

.pricing-card.popular {
  border: 2px solid #0284c7;
  box-shadow: 0 16px 40px -10px rgba(2, 132, 199, 0.2), 0 0 30px rgba(2, 132, 199, 0.15);
  transform: translateY(-8px);
}

.popular-ribbon {
  position: absolute;
  top: 14px;
  right: 14px;
  font-size: 0.74rem;
  font-weight: 800;
  color: #ffffff;
  background: var(--amber-grad);
  padding: 5px 12px;
  border-radius: 999px;
  letter-spacing: 0.5px;
  box-shadow: 0 0 12px rgba(245, 158, 11, 0.4);
}

.plan-title {
  font-size: 1.35rem;
  font-weight: 900;
  color: var(--text-heading);
  margin-bottom: 6px;
}

.plan-sub {
  font-size: 0.84rem;
  color: var(--text-muted);
  min-height: 40px;
  line-height: 1.45;
  margin-bottom: 20px;
}

.plan-price-box {
  display: flex;
  align-items: baseline;
  gap: 2px;
  margin-bottom: 24px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border-subtle);
}

.price-currency {
  font-size: 1.3rem;
  font-weight: 800;
  color: #0284c7;
}

.price-num {
  font-size: 2.6rem;
  font-weight: 900;
  color: var(--text-heading);
  line-height: 1;
}

.price-period {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-left: 4px;
}

.feature-list {
  display: flex;
  flex-direction: column;
  gap: 13px;
  margin-bottom: 30px;
}

.feature-item {
  font-size: 0.9rem;
  color: var(--text-body);
  display: flex;
  align-items: center;
  gap: 10px;
}

.feature-item .icon {
  color: #0284c7;
  font-size: 1rem;
  font-weight: 900;
}

/* -------------------------------------------------------------
   客户端下载向导 (Cross-Platform Clients)
   ------------------------------------------------------------- */
.client-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
}

.client-card {
  padding: 30px 20px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
}

.client-icon {
  font-size: 2.5rem;
  margin-bottom: 6px;
}

.client-card h4 {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text-heading);
}

.client-card p {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 10px;
}

/* -------------------------------------------------------------
   文章矩阵卡片 (SEO Articles Section)
   ------------------------------------------------------------- */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.article-card {
  padding: 30px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
}

.article-category {
  font-size: 0.76rem;
  font-weight: 800;
  color: #0284c7;
  text-transform: uppercase;
  margin-bottom: 12px;
  display: inline-block;
  background: rgba(2, 132, 199, 0.08);
  padding: 3px 10px;
  border-radius: 999px;
  border: 1px solid rgba(2, 132, 199, 0.2);
}

.article-title {
  font-size: 1.15rem;
  font-weight: 800;
  line-height: 1.45;
  margin-bottom: 12px;
  color: var(--text-heading);
}

.article-title a:hover {
  color: #0284c7;
}

.article-excerpt {
  font-size: 0.88rem;
  color: var(--text-body);
  line-height: 1.65;
  margin-bottom: 22px;
}

.article-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  color: var(--text-muted);
  padding-top: 16px;
  border-top: 1px solid var(--border-subtle);
}

.read-more {
  color: #0284c7;
  font-weight: 700;
}

.read-more:hover {
  color: #0369a1;
  text-decoration: underline;
}

/* -------------------------------------------------------------
   用户口碑评价 (Testimonials)
   ------------------------------------------------------------- */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  padding: 32px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
}

.review-stars {
  color: #f59e0b;
  font-size: 1.2rem;
  margin-bottom: 14px;
  text-shadow: 0 0 10px rgba(245, 158, 11, 0.3);
}

.review-text {
  font-size: 0.98rem;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 22px;
  font-style: italic;
}

.reviewer-meta {
  display: flex;
  align-items: center;
  gap: 12px;
}

.reviewer-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--primary-grad);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  color: #ffffff;
  font-size: 1.1rem;
  box-shadow: 0 0 16px rgba(2, 132, 199, 0.3);
}

.reviewer-name {
  font-size: 0.96rem;
  font-weight: 800;
  color: var(--text-heading);
}

.reviewer-role {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* -------------------------------------------------------------
   常见问题手风琴 (FAQ Section)
   ------------------------------------------------------------- */
.faq-wrap {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-light);
  background: var(--bg-card);
  box-shadow: var(--shadow-sm);
  transition: var(--transition-smooth);
}

.faq-question {
  padding: 22px 26px;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-heading);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
}

.faq-question:hover {
  color: #0284c7;
}

.faq-toggle-icon {
  font-size: 1.2rem;
  color: #0284c7;
  transition: transform 0.3s ease;
}

.faq-item.active .faq-toggle-icon {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  padding: 0 26px;
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.8;
}

.faq-item.active .faq-answer {
  padding: 0 26px 24px;
  max-height: 400px;
}

/* -------------------------------------------------------------
   页脚规范与友情链接 (Footer & Core Task 2 PBN Pipeline)
   ------------------------------------------------------------- */
footer {
  background: #f1f5f9;
  border-top: 1px solid var(--border-light);
  padding: 60px 0 35px;
  margin-top: 80px;
  position: relative;
  z-index: 10;
}

.footer-top {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand p {
  font-size: 0.9rem;
  color: var(--text-body);
  line-height: 1.75;
  margin-top: 14px;
  max-width: 320px;
}

.footer-col h5 {
  font-size: 0.98rem;
  font-weight: 800;
  color: var(--text-heading);
  margin-bottom: 18px;
  letter-spacing: 0.5px;
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: 11px;
}

.footer-col a {
  font-size: 0.88rem;
  color: var(--text-body);
}

.footer-col a:hover {
  color: #0284c7;
  padding-left: 3px;
}

.footer-bottom {
  padding-top: 30px;
  border-top: 1px solid var(--border-subtle);
  text-align: center;
  font-size: 0.86rem;
  color: var(--text-muted);
}

.footer-bottom p {
  margin-bottom: 14px;
}

/* 【核心任务 2：页脚 PBN 权重精准输血管道样式】 */
.footer-friend-links {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 8px;
  padding: 7px 20px;
  border-radius: 999px;
  background: #ffffff;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
}

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

.footer-friend-links a {
  color: #0284c7;
  font-weight: 700;
  transition: var(--transition-smooth);
}

.footer-friend-links a:hover {
  color: #0369a1;
  text-decoration: underline;
}

/* -------------------------------------------------------------
   文章详情页排版 (Article Layout)
   ------------------------------------------------------------- */
.article-page {
  padding: 50px 0 80px;
}

.article-container {
  max-width: 880px;
  margin: 0 auto;
  padding: 48px 52px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
}

.breadcrumb {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.breadcrumb a {
  color: #0284c7;
  font-weight: 600;
}

.breadcrumb a:hover {
  color: #0369a1;
  text-decoration: underline;
}

.article-header-title {
  font-size: 2.2rem;
  font-weight: 900;
  line-height: 1.35;
  color: var(--text-heading);
  margin-bottom: 20px;
}

.article-header-meta {
  display: flex;
  align-items: center;
  gap: 20px;
  font-size: 0.86rem;
  color: var(--text-muted);
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 34px;
  flex-wrap: wrap;
}

.article-body {
  font-size: 1.05rem;
  color: var(--text-body);
  line-height: 1.85;
}

.article-body p {
  margin-bottom: 22px;
}

.article-body h2 {
  font-size: 1.55rem;
  font-weight: 800;
  color: var(--text-heading);
  margin: 40px 0 18px;
  padding-left: 14px;
  border-left: 4px solid var(--primary);
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-heading);
  margin: 28px 0 12px;
}

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

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

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

.article-body li {
  margin-bottom: 10px;
}

.article-body blockquote {
  margin: 26px 0;
  padding: 20px 24px;
  background: var(--bg-soft);
  border-left: 4px solid var(--primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-style: italic;
  color: var(--text-main);
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 30px 0;
  font-size: 0.94rem;
  background: var(--bg-item);
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-light);
}

.article-body th, .article-body td {
  padding: 14px 18px;
  border: 1px solid var(--border-subtle);
  text-align: left;
}

.article-body th {
  background: var(--bg-soft);
  color: var(--text-heading);
  font-weight: 700;
}

/* -------------------------------------------------------------
   响应式媒体查询 (Mobile & Tablet Responsiveness)
   ------------------------------------------------------------- */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .bento-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .bento-card.span-2 {
    grid-column: span 2;
  }
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-card.popular {
    transform: none;
  }
  .footer-top {
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
  }
  .articles-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: 74px;
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.98);
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 30px 20px;
    gap: 20px;
    border-bottom: 1px solid var(--border-light);
    transform: translateY(-150%);
    transition: transform 0.3s ease-in-out;
  }

  .nav-menu.active {
    transform: translateY(0);
  }

  .mobile-toggle {
    display: block;
  }

  .nav-cta-group .btn-secondary {
    display: none;
  }

  .hero-title {
    font-size: 2.2rem;
  }

  .hero-stats-row {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
  }

  .workflow-pipeline {
    flex-direction: column;
    gap: 8px;
  }

  .pipe-node {
    width: 100%;
  }

  .pipe-connector {
    width: 100%;
    transform: none;
    flex-direction: row;
    justify-content: center;
    gap: 8px;
  }

  .pipe-line {
    width: 40px;
    height: 2px;
  }

  .bento-grid {
    grid-template-columns: 1fr;
  }
  .bento-card.span-2 {
    grid-column: span 1;
  }

  .pricing-grid {
    grid-template-columns: 1fr;
  }

  .client-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .articles-grid {
    grid-template-columns: 1fr;
  }

  .reviews-grid {
    grid-template-columns: 1fr;
  }

  .article-container {
    padding: 26px 20px;
  }

  .article-header-title {
    font-size: 1.65rem;
  }

  .footer-top {
    grid-template-columns: 1fr;
  }
}