/* ==========================================================================
   尔湾云 (erwanyun-jc.homes) - 奢华极简设计系统 (Luxury Minimalist)
   设计主张：黑曜石沉稳暗调、香槟金雅致点缀、奶油白柔和字韵、经典中文衬线、粗圆品牌标题、精致间距
   ========================================================================== */

:root {
  /* 奢华基调配色 (黑色、奶油白、香槟金) */
  --bg-primary: #09090b;       /* 黑曜石深邃底色 */
  --bg-secondary: #121216;     /* 炭黑丝绒层 */
  --bg-surface: #181820;       /* 雅致深灰表面 */
  --bg-surface-hover: #22222c; /* 悬浮深灰 */
  --bg-glass: rgba(15, 15, 19, 0.88);
  
  --bg-cream: #faf7f2;         /* 纯正奶油白 */
  --text-primary: #fcfaf6;     /* 柔和奶油白主字色 */
  --text-secondary: #b5b0a7;   /* 雅致砂岩浅褐副字色 */
  --text-muted: #78736a;       /* 沉稳古铜灰辅字色 */
  
  /* 奢华点缀金与柔和雅色 */
  --accent-gold: #c5a472;       /* 核心香槟金 */
  --accent-gold-light: #e5cf9e; /* 明亮香槟金 */
  --accent-gold-dark: #997843;  /* 沉稳古铜金 */
  --accent-cream: #f4f0e6;      /* 暖奶油色 */
  --accent-emerald: #52a472;    /* 典雅翡翠绿 (状态指示) */

  /* 精致发丝边框与高光 */
  --border-dim: rgba(197, 164, 114, 0.15);
  --border-bright: rgba(197, 164, 114, 0.32);
  --border-highlight: #c5a472;
  
  /* 字体系统：粗圆品牌风格 + 经典衬线标题 + 精致正文 */
  --font-rounded: ui-rounded, "SF Pro Rounded", "Hiragino Maru Gothic ProN", "Microsoft YaHei UI", "Microsoft YaHei", sans-serif;
  --font-serif: "Songti SC", "Source Han Serif SC", "Noto Serif SC", "STSong", "SimSun", Georgia, "Times New Roman", serif;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  /* 精致间距与倒角系统 */
  --header-height: 76px;
  --container-max: 1200px;
  --radius-xs: 4px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-pill: 9999px;
  --transition: 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.8;
  overflow-x: hidden;
  position: relative;
  min-height: 100vh;
  letter-spacing: 0.01em;
  background-image: 
    radial-gradient(ellipse 70% 38% at 50% 0%, rgba(197, 164, 114, 0.08), transparent 70%),
    radial-gradient(ellipse 50% 30% at 85% 60%, rgba(197, 164, 114, 0.04), transparent 60%);
  background-attachment: fixed;
}

/* 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;
  }
}

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

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

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

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 28px;
  padding-right: 28px;
}

/* Typography Helpers */
.mono {
  font-family: var(--font-mono);
}

/* 奢华极简标签：优雅衬线大写、精致字间距与金线轮廓 */
.sec-tag {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-serif);
  font-size: 0.78125rem;
  letter-spacing: 0.2em;
  color: var(--accent-gold);
  background: rgba(197, 164, 114, 0.06);
  border: 1px solid rgba(197, 164, 114, 0.24);
  padding: 6px 18px;
  border-radius: var(--radius-pill);
  margin-bottom: 20px;
  text-transform: uppercase;
  font-weight: 500;
}

.sec-tag::before {
  content: "✦";
  display: inline-block;
  font-size: 0.6875rem;
  color: var(--accent-gold-light);
}

/* 章节主标题：沉稳大气的中文经典衬线 */
.sec-title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 3.8vw, 2.75rem);
  font-weight: 600;
  line-height: 1.35;
  color: var(--text-primary);
  margin-bottom: 16px;
  letter-spacing: 0.02em;
}

.sec-desc {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  max-width: 720px;
  line-height: 1.85;
  letter-spacing: 0.01em;
}

/* 键盘焦点可访问性 */
:focus-visible {
  outline: 2px solid var(--accent-gold);
  outline-offset: 3px;
}

/* ==========================================================================
   页眉 Header & Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-dim);
}

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

/* 品牌标题：采用明确指定的粗圆字体风格 */
.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-rounded);
  font-weight: 800;
  font-size: 1.375rem;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.brand-logo img {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  filter: drop-shadow(0 2px 8px rgba(197, 164, 114, 0.25));
}

.brand-badge {
  font-family: var(--font-serif);
  font-size: 0.6875rem;
  padding: 3px 8px;
  border: 1px solid var(--border-bright);
  border-radius: var(--radius-pill);
  color: var(--accent-gold);
  background: rgba(197, 164, 114, 0.08);
  letter-spacing: 0.08em;
  font-weight: 500;
}

.nav-desktop {
  display: flex;
  align-items: center;
  gap: 36px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-link {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  font-weight: 500;
  letter-spacing: 0.02em;
  position: relative;
  padding: 8px 0;
}

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

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

.nav-link.highlight {
  color: var(--accent-gold-light);
  font-family: var(--font-serif);
  letter-spacing: 0.06em;
  font-size: 0.9375rem;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* 奢华质感按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 0.9375rem;
  font-weight: 600;
  padding: 11px 24px;
  border-radius: var(--radius-pill);
  transition: all var(--transition);
  text-align: center;
  white-space: nowrap;
  letter-spacing: 0.02em;
}

/* 主按钮：香槟金柔滑渐变、深邃暗黑文字、典雅微光 */
.btn-primary {
  background: linear-gradient(135deg, #e4cd9f 0%, #c5a472 50%, #ac874e 100%);
  color: #0d0c0a;
  border: 1px solid #ebd7b3;
  box-shadow: 0 4px 18px rgba(197, 164, 114, 0.22);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #eee0b8 0%, #d4b484 50%, #bb965d 100%);
  box-shadow: 0 6px 26px rgba(197, 164, 114, 0.38);
  transform: translateY(-2px);
}

/* 次按钮：黑曜石半透底色、精致发丝金边 */
.btn-secondary {
  background: rgba(24, 24, 32, 0.6);
  color: var(--text-primary);
  border: 1px solid rgba(197, 164, 114, 0.3);
  backdrop-filter: blur(8px);
}

.btn-secondary:hover {
  background: rgba(36, 36, 46, 0.9);
  border-color: var(--accent-gold);
  color: #ffffff;
  transform: translateY(-2px);
}

.btn-sm {
  padding: 7px 16px;
  font-size: 0.8125rem;
}

/* Mobile Toggle */
.mobile-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--border-dim);
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  color: var(--text-primary);
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

/* Mobile Nav Drawer */
.mobile-nav-panel {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-dim);
  padding: 24px;
  z-index: 99;
}

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

.mobile-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 24px;
}

.mobile-nav-list a {
  display: block;
  font-size: 1.0625rem;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-dim);
}

/* ==========================================================================
   主视觉 Hero Section
   ========================================================================== */
.sec-hero {
  padding: clamp(64px, 10vw, 112px) 0 clamp(48px, 7vw, 96px);
  position: relative;
  border-bottom: 1px solid var(--border-dim);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 56px;
  align-items: center;
}

.hero-content {
  display: flex;
  flex-direction: column;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2.4rem, 4.8vw, 3.6rem);
  font-weight: 700;
  line-height: 1.22;
  letter-spacing: 0.02em;
  color: var(--text-primary);
  margin-bottom: 24px;
}

.hero-title .text-gradient {
  background: linear-gradient(135deg, #fefdfb 0%, #e2cc9f 50%, #c5a472 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  font-size: 1.125rem;
  color: var(--text-secondary);
  line-height: 1.85;
  margin-bottom: 36px;
  letter-spacing: 0.01em;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 44px;
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  padding-top: 32px;
  border-top: 1px solid var(--border-dim);
}

.metric-item {
  display: flex;
  flex-direction: column;
}

.metric-val {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--accent-gold-light);
  line-height: 1.2;
}

.metric-val.green { color: var(--accent-gold-light); }
.metric-val.cyan { color: var(--accent-gold); }
.metric-val.blue { color: var(--accent-cream); }

.metric-label {
  font-size: 0.8125rem;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  margin-top: 6px;
}

/* 奢华监控面板 (Hero Dynamic Card) */
.hero-card-wrapper {
  position: relative;
}

.hero-tech-card {
  background: linear-gradient(180deg, rgba(26, 26, 34, 0.9) 0%, rgba(17, 17, 23, 0.95) 100%);
  border: 1px solid var(--border-bright);
  border-radius: var(--radius-md);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.6), inset 0 1px 0 rgba(255, 255, 255, 0.06);
  overflow: hidden;
  position: relative;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  background: rgba(14, 14, 18, 0.95);
  border-bottom: 1px solid var(--border-dim);
}

.card-dots {
  display: flex;
  gap: 8px;
}

.dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  opacity: 0.75;
}
.dot-red { background: #964848; }
.dot-yellow { background: #ab8b54; }
.dot-green { background: #528c68; }

.card-terminal-title {
  font-family: var(--font-serif);
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.card-body {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.circuit-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 18px;
  background: var(--bg-primary);
  border: 1px solid var(--border-dim);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  transition: border-color var(--transition);
}

.circuit-row:hover {
  border-color: var(--border-bright);
}

.circuit-name {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-primary);
  font-weight: 500;
}

.status-indicator {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent-gold);
  box-shadow: 0 0 10px var(--accent-gold);
}

.circuit-ping {
  color: var(--accent-gold-light);
  font-family: var(--font-serif);
  font-weight: 600;
}

.circuit-tag {
  font-size: 0.75rem;
  color: var(--text-muted);
  background: rgba(197, 164, 114, 0.08);
  padding: 3px 8px;
  border-radius: var(--radius-xs);
  border: 1px solid var(--border-dim);
}

.card-foot-notice {
  font-size: 0.78125rem;
  color: var(--text-muted);
  line-height: 1.6;
  border-top: 1px solid var(--border-dim);
  padding-top: 14px;
}

/* ==========================================================================
   核心优势 Advantages Section
   ========================================================================== */
.sec-advantages {
  padding: clamp(64px, 8vw, 100px) 0;
  border-bottom: 1px solid var(--border-dim);
}

.adv-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
  margin-top: 56px;
}

.adv-card {
  background: linear-gradient(180deg, rgba(24, 24, 32, 0.8) 0%, rgba(18, 18, 24, 0.95) 100%);
  border: 1px solid var(--border-dim);
  border-radius: var(--radius-md);
  padding: 40px 32px;
  position: relative;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.35);
}

.adv-card:hover {
  border-color: var(--border-bright);
  background: linear-gradient(180deg, rgba(30, 30, 40, 0.9) 0%, rgba(22, 22, 30, 0.98) 100%);
  transform: translateY(-3px);
  box-shadow: 0 20px 48px rgba(0, 0, 0, 0.55), 0 0 24px rgba(197, 164, 114, 0.08);
}

.adv-num {
  font-family: var(--font-serif);
  font-size: 0.875rem;
  color: var(--accent-gold);
  letter-spacing: 0.15em;
  margin-bottom: 20px;
  font-weight: 500;
}

.adv-icon-wrap {
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(197, 164, 114, 0.08);
  border: 1px solid rgba(197, 164, 114, 0.22);
  border-radius: var(--radius-sm);
  color: var(--accent-gold);
  margin-bottom: 24px;
}

.adv-title {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 14px;
  letter-spacing: 0.02em;
}

.adv-text {
  font-size: 0.96875rem;
  color: var(--text-secondary);
  line-height: 1.8;
}

/* ==========================================================================
   流媒体与 AI 支持 Section
   ========================================================================== */
.sec-media-ai {
  padding: clamp(64px, 8vw, 100px) 0;
  border-bottom: 1px solid var(--border-dim);
  background: var(--bg-secondary);
}

.media-ai-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  margin-top: 56px;
}

.media-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-dim);
  border-radius: var(--radius-md);
  padding: 30px 24px;
  transition: all var(--transition);
}

.media-item:hover {
  border-color: var(--border-bright);
  transform: translateY(-2px);
}

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

.media-title {
  font-family: var(--font-serif);
  font-size: 1.1875rem;
  font-weight: 600;
  color: var(--text-primary);
}

.media-badge {
  font-size: 0.71875rem;
  padding: 3px 9px;
  border-radius: var(--radius-pill);
  background: rgba(197, 164, 114, 0.1);
  color: var(--accent-gold-light);
  border: 1px solid rgba(197, 164, 114, 0.25);
  letter-spacing: 0.04em;
}

.media-desc {
  font-size: 0.90625rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 20px;
}

.media-condition {
  font-size: 0.78125rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-dim);
  padding-top: 12px;
  line-height: 1.6;
}

.media-disclaimer {
  margin-top: 36px;
  padding: 18px 24px;
  border-radius: var(--radius-sm);
  background: rgba(197, 164, 114, 0.05);
  border: 1px solid rgba(197, 164, 114, 0.22);
  font-size: 0.90625rem;
  color: #dfc8a0;
  line-height: 1.75;
}

/* ==========================================================================
   套餐资费对比 Pricing Section
   ========================================================================== */
.sec-pricing {
  padding: clamp(64px, 8vw, 100px) 0;
  border-bottom: 1px solid var(--border-dim);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 28px;
  margin-top: 56px;
}

.price-card {
  background: linear-gradient(180deg, rgba(24, 24, 32, 0.8) 0%, rgba(18, 18, 24, 0.95) 100%);
  border: 1px solid var(--border-dim);
  border-radius: var(--radius-md);
  padding: 40px 28px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.35);
}

.price-card:hover {
  border-color: var(--border-bright);
  transform: translateY(-3px);
  box-shadow: 0 20px 48px rgba(0, 0, 0, 0.55);
}

.price-card.featured {
  border-color: var(--accent-gold);
  background: linear-gradient(180deg, rgba(32, 30, 38, 0.95) 0%, rgba(20, 19, 25, 0.98) 100%);
  box-shadow: 0 0 0 1px var(--accent-gold), 0 24px 56px rgba(0, 0, 0, 0.7), 0 0 32px rgba(197, 164, 114, 0.12);
}

.featured-flag {
  position: absolute;
  top: -12px;
  right: 24px;
  background: linear-gradient(135deg, #e4cd9f 0%, #c5a472 100%);
  color: #0c0b09;
  font-family: var(--font-serif);
  font-size: 0.6875rem;
  font-weight: 700;
  padding: 3px 12px;
  border-radius: var(--radius-pill);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.price-name {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.price-cycle {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-bottom: 22px;
}

.price-figure {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 22px;
}

.price-currency {
  font-size: 1.375rem;
  font-weight: 600;
  color: var(--accent-gold);
}

.price-amount {
  font-family: var(--font-serif);
  font-size: 2.75rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1;
}

.price-period {
  font-size: 0.90625rem;
  color: var(--text-secondary);
}

.price-traffic {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(197, 164, 114, 0.08);
  border: 1px solid rgba(197, 164, 114, 0.22);
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--accent-gold-light);
  margin-bottom: 28px;
}

.price-features {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 36px;
  flex-grow: 1;
}

.price-feature-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.90625rem;
  color: var(--text-secondary);
}

.price-feature-item::before {
  content: "✦";
  font-size: 0.75rem;
  color: var(--accent-gold);
}

.price-btn {
  width: 100%;
}

.pricing-note {
  margin-top: 36px;
  text-align: center;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ==========================================================================
   品牌架构全景技术综述 Section
   ========================================================================== */
.sec-overview {
  padding: clamp(64px, 8vw, 100px) 0;
  border-bottom: 1px solid var(--border-dim);
  background: var(--bg-secondary);
}

.overview-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-dim);
  border-radius: var(--radius-md);
  padding: clamp(28px, 6vw, 56px);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.4);
}

.overview-content {
  color: var(--text-secondary);
  font-size: 1.03125rem;
  line-height: 1.9;
}

.overview-content h3 {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  color: var(--text-primary);
  margin-top: 36px;
  margin-bottom: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.overview-content h3:first-child {
  margin-top: 0;
}

.overview-content p {
  margin-bottom: 18px;
}

/* ==========================================================================
   常见问题答疑 FAQ Section
   ========================================================================== */
.sec-faq {
  padding: clamp(64px, 8vw, 100px) 0;
  border-bottom: 1px solid var(--border-dim);
}

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: 56px;
  max-width: 920px;
}

.faq-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-dim);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: all var(--transition);
}

.faq-item:hover {
  border-color: var(--border-bright);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 22px 28px;
  text-align: left;
  font-family: var(--font-serif);
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  background: transparent;
  letter-spacing: 0.01em;
}

.faq-icon {
  font-size: 1.25rem;
  color: var(--accent-gold);
  transition: transform var(--transition);
}

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

.faq-answer {
  display: none;
  padding: 0 28px 24px 28px;
  font-size: 0.96875rem;
  color: var(--text-secondary);
  line-height: 1.8;
  border-top: 1px solid var(--border-dim);
  padding-top: 18px;
}

.faq-item.active .faq-answer {
  display: block;
}

/* ==========================================================================
   知识科普预览入口 Section
   ========================================================================== */
.sec-knowledge-preview {
  padding: clamp(64px, 8vw, 100px) 0;
  border-bottom: 1px solid var(--border-dim);
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 28px;
  margin-top: 56px;
}

.preview-card {
  background: linear-gradient(180deg, rgba(24, 24, 32, 0.8) 0%, rgba(18, 18, 24, 0.95) 100%);
  border: 1px solid var(--border-dim);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  transition: all var(--transition);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.35);
}

.preview-card:hover {
  border-color: var(--border-bright);
  transform: translateY(-2px);
  box-shadow: 0 18px 44px rgba(0, 0, 0, 0.5);
}

.preview-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.78125rem;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.preview-title {
  font-family: var(--font-serif);
  font-size: 1.1875rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 12px;
  line-height: 1.45;
}

.preview-title a:hover {
  color: var(--accent-gold-light);
}

.preview-excerpt {
  font-size: 0.90625rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 24px;
  flex-grow: 1;
}

.preview-link {
  font-size: 0.875rem;
  color: var(--accent-gold);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-weight: 600;
}

.preview-link:hover {
  color: var(--accent-gold-light);
}

.preview-more-box {
  margin-top: 48px;
  text-align: center;
}

/* ==========================================================================
   隐藏用户评价模块 (按真实资料核实要求)
   ========================================================================== */
.sec-reviews {
  display: none !important;
}

/* ==========================================================================
   右侧章节悬浮控制器 (上一章节 / 下一章节)
   ========================================================================== */
.side-nav-controller {
  position: fixed;
  right: 24px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 90;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-bright);
  padding: 10px 6px;
  border-radius: var(--radius-pill);
  box-shadow: 0 12px 36px rgba(0, 0, 0, 0.6);
}

.side-btn {
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--bg-surface);
  border: 1px solid var(--border-dim);
  color: var(--accent-gold);
  transition: all var(--transition);
}

.side-btn:hover:not(:disabled) {
  background: rgba(197, 164, 114, 0.15);
  border-color: var(--accent-gold);
  color: #ffffff;
}

.side-btn:disabled {
  opacity: 0.25;
  cursor: not-allowed;
  border-color: var(--border-dim);
}

.side-btn img, .side-btn svg {
  width: 18px;
  height: 18px;
}

.side-indicator {
  font-family: var(--font-serif);
  font-size: 0.6875rem;
  color: var(--accent-gold);
  padding: 4px 0;
  text-align: center;
  font-weight: 600;
  user-select: none;
  letter-spacing: 0.05em;
}

/* ==========================================================================
   页脚 Footer
   ========================================================================== */
.site-footer {
  background: var(--bg-primary);
  border-top: 1px solid var(--border-dim);
  padding: 68px 0 44px;
}

.footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 28px;
  padding-bottom: 36px;
  border-bottom: 1px solid var(--border-dim);
}

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

.footer-nav {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
  flex-wrap: wrap;
}

.footer-nav a {
  font-size: 0.9375rem;
  color: var(--text-secondary);
}

.footer-nav a:hover {
  color: var(--accent-gold);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  padding-top: 32px;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ==========================================================================
   知识科普专栏文章通用排版
   ========================================================================== */
.article-header {
  padding: 56px 0 36px;
  border-bottom: 1px solid var(--border-dim);
  margin-bottom: 44px;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-bottom: 18px;
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--accent-gold);
}

.article-title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 3.8vw, 2.65rem);
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.35;
  margin-bottom: 22px;
  letter-spacing: 0.02em;
}

.article-meta-bar {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 0.8125rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}

.article-meta-bar span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.article-body {
  max-width: 860px;
  margin: 0 auto;
  font-size: 1.0625rem;
  line-height: 1.95;
  color: #dcd8d0;
  letter-spacing: 0.01em;
}

.article-body h2 {
  font-family: var(--font-serif);
  font-size: 1.625rem;
  color: var(--text-primary);
  margin-top: 54px;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-dim);
  font-weight: 600;
  letter-spacing: 0.02em;
}

.article-body h3 {
  font-family: var(--font-serif);
  font-size: 1.3125rem;
  color: var(--text-primary);
  margin-top: 36px;
  margin-bottom: 16px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

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

.article-body ul, .article-body ol {
  margin-bottom: 28px;
  padding-left: 28px;
}

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

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

.article-body blockquote {
  border-left: 3px solid var(--accent-gold);
  padding: 18px 24px;
  background: var(--bg-surface);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 28px 0;
  color: var(--text-secondary);
  font-size: 0.96875rem;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 32px 0;
  font-size: 0.90625rem;
  background: var(--bg-surface);
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--border-dim);
}

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

.article-body th {
  background: var(--bg-secondary);
  color: var(--accent-gold-light);
  font-family: var(--font-serif);
  font-weight: 600;
}

.article-callout {
  margin: 44px 0;
  padding: 32px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(36, 32, 28, 0.7) 0%, rgba(24, 22, 20, 0.85) 100%);
  border: 1px solid var(--border-bright);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.4);
}

.article-callout h4 {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  color: var(--text-primary);
  margin-bottom: 12px;
  letter-spacing: 0.02em;
}

.article-callout p {
  margin-bottom: 20px;
  font-size: 0.96875rem;
  color: var(--text-secondary);
  line-height: 1.8;
}

/* ==========================================================================
   响应式设计与断点优化 (Mobile First & Tablet)
   ========================================================================== */
@media (max-width: 992px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

@media (max-width: 768px) {
  .nav-desktop {
    display: none;
  }
  .mobile-toggle {
    display: flex;
  }
  .hero-metrics {
    grid-template-columns: 1fr;
    gap: 18px;
  }
  .side-nav-controller {
    right: 12px;
    bottom: 20px;
    top: auto;
    transform: none;
    flex-direction: row;
    padding: 6px 12px;
  }
  .side-indicator {
    padding: 0 8px;
  }
  .footer-top {
    flex-direction: column;
    align-items: flex-start;
  }
  .footer-nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }
}