/* ==========================================================================
   Imm Telecom - Stealth OLED Minimalist Monochrome Design System
   UI Specification:
   - Palette: Pitch darkroom black (#000000), Stark titanium white (#ffffff), 
     Faint hairline border platinum (#1c1c1f / #e5e5e5)
   - Strictly zero generic AI badges
   - Void-monolith layout: extreme negative space, clinical monospace metrics
   - Photon-pulse micro-interactions, smooth anchor transitions, OLED pure perfection
   ========================================================================== */

:root {
  /* 白天极简纯粹模式 (Light Mode - Swiss Architectural Minimalist) */
  --bg-void: #ffffff;
  --bg-surface: #fafafa;
  --bg-card: #f4f4f5;
  --bg-card-hover: #ececeebb;
  --bg-elevated: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.92);

  --text-pure: #000000;
  --text-secondary: #27272a;
  --text-muted: #71717a;
  --text-faint: #a1a1aa;
  --text-inverse: #ffffff;

  --border-hairline: #e4e4e7;
  --border-subtle: #d4d4d8;
  --border-focus: #000000;

  --mono-accent: #18181b;
  --photon-color: #000000;
  --fiber-color: rgba(0, 0, 0, 0.12);

  --btn-bg: #000000;
  --btn-text: #ffffff;
  --btn-border: #000000;
  --btn-hover-bg: #27272a;

  --btn-secondary-bg: #ffffff;
  --btn-secondary-text: #000000;
  --btn-secondary-border: #d4d4d8;
  --btn-secondary-hover-bg: #f4f4f5;

  --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
  --card-hover-shadow: 0 12px 24px -10px rgba(0, 0, 0, 0.08);

  --toggle-bg: rgba(0, 0, 0, 0.05);
  --toggle-border: rgba(0, 0, 0, 0.12);
  --toggle-icon: #000000;
}

[data-theme="dark"] {
  /* Stealth OLED True-Black Mode */
  --bg-void: #000000;
  --bg-surface: #09090b;
  --bg-card: #0d0d10;
  --bg-card-hover: #141418;
  --bg-elevated: #111115;
  --bg-glass: rgba(0, 0, 0, 0.88);

  --text-pure: #ffffff;
  --text-secondary: #e4e4e7;
  --text-muted: #8e8e93;
  --text-faint: #52525b;
  --text-inverse: #000000;

  --border-hairline: #1c1c1f;
  --border-subtle: #27272a;
  --border-focus: #ffffff;

  --mono-accent: #f4f4f5;
  --photon-color: #ffffff;
  --fiber-color: rgba(255, 255, 255, 0.15);

  --btn-bg: #ffffff;
  --btn-text: #000000;
  --btn-border: #ffffff;
  --btn-hover-bg: #e4e4e7;

  --btn-secondary-bg: transparent;
  --btn-secondary-text: #ffffff;
  --btn-secondary-border: #27272a;
  --btn-secondary-hover-bg: #141418;

  --card-shadow: none;
  --card-hover-shadow: 0 0 30px rgba(255, 255, 255, 0.03);

  --toggle-bg: rgba(255, 255, 255, 0.06);
  --toggle-border: rgba(255, 255, 255, 0.14);
  --toggle-icon: #ffffff;
}

/* 全局重置与平滑滚动 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Inter", "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: var(--bg-void);
  color: var(--text-pure);
  line-height: 1.6;
  overflow-x: hidden;
  letter-spacing: -0.012em;
  transition: background-color 0.35s cubic-bezier(0.16, 1, 0.3, 1),
              color 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

/* 临床式等宽数字与遥测字体 */
.mono-telemetry,
.telemetry-tag,
.server-code,
.transit-badge {
  font-family: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, "Courier New", monospace;
  letter-spacing: 0.02em;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 28px;
}

/* ==========================================================================
   页眉与导航目录 (Sticky Header)
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-hairline);
  transition: border-color 0.3s ease, background-color 0.3s ease;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  color: var(--text-pure);
  user-select: none;
}

.brand-dot {
  width: 8px;
  height: 8px;
  background-color: var(--text-pure);
  border-radius: 50%;
  display: inline-block;
  box-shadow: 0 0 10px var(--text-pure);
}

.nav-links {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 24px;
}

.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.2s ease, opacity 0.2s ease;
  position: relative;
  padding: 6px 0;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-pure);
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: var(--text-pure);
}

.nav-badge-pill {
  font-size: 0.72rem;
  padding: 2px 6px;
  border: 1px solid var(--border-subtle);
  border-radius: 4px;
  margin-left: 4px;
  color: var(--text-pure);
  text-transform: uppercase;
  font-family: ui-monospace, monospace;
}

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

/* 精致透明化专业昼夜模式切换按钮 */
.theme-toggle-btn {
  background: var(--toggle-bg);
  border: 1px solid var(--toggle-border);
  color: var(--toggle-icon);
  width: 38px;
  height: 38px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  position: relative;
  outline: none;
}

.theme-toggle-btn:hover {
  border-color: var(--border-focus);
  transform: scale(1.05);
}

.theme-icon-sun,
.theme-icon-moon {
  width: 18px;
  height: 18px;
  transition: transform 0.35s ease, opacity 0.35s ease;
  position: absolute;
}

[data-theme="light"] .theme-icon-sun,
:root:not([data-theme="dark"]) .theme-icon-sun {
  opacity: 0;
  transform: rotate(90deg) scale(0.4);
  pointer-events: none;
}

[data-theme="light"] .theme-icon-moon,
:root:not([data-theme="dark"]) .theme-icon-moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

[data-theme="dark"] .theme-icon-moon {
  opacity: 0;
  transform: rotate(-90deg) scale(0.4);
  pointer-events: none;
}

[data-theme="dark"] .theme-icon-sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

/* 按钮极简规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 600;
  font-size: 0.88rem;
  padding: 8px 18px;
  border-radius: 8px;
  border: 1px solid transparent;
  cursor: pointer;
  text-align: center;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  white-space: nowrap;
  letter-spacing: -0.01em;
}

.btn-primary {
  background: var(--btn-bg);
  color: var(--btn-text) !important;
  border: 1px solid var(--btn-border);
}

.btn-primary:hover {
  background: var(--btn-hover-bg);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--btn-secondary-bg);
  color: var(--btn-secondary-text);
  border: 1px solid var(--btn-secondary-border);
}

.btn-secondary:hover {
  background: var(--btn-secondary-hover-bg);
  border-color: var(--border-focus);
  transform: translateY(-1px);
}

.btn-lg {
  padding: 12px 28px;
  font-size: 0.95rem;
  border-radius: 10px;
}

.btn-block {
  width: 100%;
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text-pure);
  cursor: pointer;
  padding: 6px;
}

/* ==========================================================================
   主视觉区 (Void-Monolith Hero & Photon-Pulse Micro-Interactions)
   ========================================================================== */
.hero-section {
  padding: 100px 0 80px;
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--border-hairline);
}

.hero-telemetry-strip {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 920px;
  margin: 0 auto 32px;
  padding: 8px 16px;
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: 8px;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.telemetry-status-dot {
  width: 6px;
  height: 6px;
  background: #10b981;
  border-radius: 50%;
  display: inline-block;
  margin-right: 6px;
}

.hero-title {
  font-size: clamp(1.15rem, 3.5vw, 2.85rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
  text-align: center;
  max-width: 100%;
  margin: 0 auto 20px;
  color: var(--text-pure);
  white-space: nowrap;
  text-wrap: nowrap;
}

.hero-subtitle {
  font-size: 1.15rem;
  line-height: 1.65;
  color: var(--text-muted);
  text-align: center;
  max-width: 780px;
  margin: 0 auto 36px;
  font-weight: 400;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 50px;
}

/* 1px 水平光纤矢量与脉冲光子微交互 (Photon-Pulse Fiber Vector) */
.photon-canvas-container {
  max-width: 920px;
  margin: 0 auto 36px;
  position: relative;
  padding: 24px 0;
}

.fiber-track {
  width: 100%;
  height: 1px;
  background: var(--fiber-color);
  position: relative;
}

.photon-bead {
  position: absolute;
  top: -2px;
  left: 0;
  width: 5px;
  height: 5px;
  background-color: var(--photon-color);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--photon-color), 0 0 4px var(--photon-color);
  animation: photonPulse 4.5s cubic-bezier(0.4, 0, 0.2, 1) infinite;
}

@keyframes photonPulse {
  0% { left: 0%; opacity: 0; transform: scale(0.6); }
  5% { opacity: 1; transform: scale(1.2); }
  95% { opacity: 1; transform: scale(1); }
  100% { left: 100%; opacity: 0; transform: scale(0.6); }
}

.fiber-endpoints {
  display: flex;
  justify-content: space-between;
  margin-top: 10px;
  font-size: 0.76rem;
  color: var(--text-muted);
}

.endpoint-ingress,
.endpoint-egress {
  display: flex;
  flex-direction: column;
}

.endpoint-name {
  color: var(--text-pure);
  font-weight: 600;
}

/* 临床式网络参数统计条 */
.hero-specs-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  max-width: 920px;
  margin: 0 auto;
}

.spec-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: 10px;
  padding: 16px 20px;
  position: relative;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.spec-card:hover {
  border-color: var(--border-focus);
}

.spec-label {
  font-size: 0.76rem;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.spec-value {
  font-size: 1.55rem;
  font-weight: 700;
  color: var(--text-pure);
  letter-spacing: -0.03em;
  line-height: 1.1;
}

/* 呼吸式遥测数据：悬停时从 20% 平滑呼吸至 100% */
.spec-telemetry-reveal {
  font-size: 0.72rem;
  color: var(--text-muted);
  margin-top: 8px;
  opacity: 0.25;
  transition: opacity 0.3s cubic-bezier(0.16, 1, 0.3, 1), color 0.3s ease;
}

.spec-card:hover .spec-telemetry-reveal {
  opacity: 1;
  color: var(--text-pure);
}

/* ==========================================================================
   通用区块排版 (Void-Monolith Layout)
   ========================================================================== */
.section {
  padding: 90px 0;
  border-bottom: 1px solid var(--border-hairline);
  position: relative;
}

.section-header {
  max-width: 800px;
  margin: 0 auto 55px;
  text-align: center;
}

.section-tag {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 12px;
}

.section-title {
  font-size: 2.3rem;
  font-weight: 800;
  color: var(--text-pure);
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 14px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ==========================================================================
   产品核心优势介绍 (3个图文卡片)
   ========================================================================== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-hairline);
  border-radius: 14px;
  padding: 32px 28px;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  display: flex;
  flex-direction: column;
  position: relative;
}

.feature-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-focus);
  transform: translateY(-3px);
}

.feature-serial {
  font-size: 0.76rem;
  color: var(--text-faint);
  margin-bottom: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.feature-icon-monochrome {
  width: 32px;
  height: 32px;
  color: var(--text-pure);
  margin-bottom: 20px;
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-pure);
  letter-spacing: -0.02em;
  margin-bottom: 10px;
}

.feature-desc {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 20px;
  flex-grow: 1;
}

.feature-telemetry-box {
  padding-top: 16px;
  border-top: 1px solid var(--border-hairline);
  font-size: 0.78rem;
  color: var(--text-faint);
  display: flex;
  flex-direction: column;
  gap: 6px;
  transition: color 0.25s ease;
}

.feature-card:hover .feature-telemetry-box {
  color: var(--text-secondary);
}

.telemetry-row {
  display: flex;
  justify-content: space-between;
}

/* ==========================================================================
   流媒体图卡 & AI 支持图卡 (严苛纯黑白极简 · 坚决拒绝通用彩标)
   ========================================================================== */
.showcase-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.showcase-card {
  background: var(--bg-card);
  border: 1px solid var(--border-hairline);
  border-radius: 14px;
  padding: 36px 32px;
  transition: border-color 0.25s ease, background 0.25s ease;
  display: flex;
  flex-direction: column;
}

.showcase-card:hover {
  border-color: var(--border-focus);
  background: var(--bg-card-hover);
}

.showcase-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
}

.showcase-badge {
  font-size: 0.75rem;
  text-transform: uppercase;
  color: var(--text-muted);
  border: 1px solid var(--border-subtle);
  padding: 3px 8px;
  border-radius: 4px;
}

.showcase-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-pure);
  margin-bottom: 10px;
  letter-spacing: -0.02em;
}

.showcase-desc {
  font-size: 0.94rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 24px;
}

/* 纯单色极简平台清单 (Minimalist Monochrome Matrix) */
.monochrome-matrix {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-bottom: 28px;
}

.matrix-item {
  border: 1px solid var(--border-hairline);
  border-radius: 8px;
  padding: 10px 14px;
  background: var(--bg-surface);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.86rem;
  transition: border-color 0.2s ease;
}

.matrix-item:hover {
  border-color: var(--border-focus);
}

.matrix-name {
  font-weight: 600;
  color: var(--text-pure);
}

.matrix-tag {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.showcase-footer {
  margin-top: auto;
  padding-top: 18px;
  border-top: 1px solid var(--border-hairline);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* ==========================================================================
   套餐价格对比表 (参考网上真实机场/加速器主流套餐行情)
   ========================================================================== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-hairline);
  border-radius: 14px;
  padding: 36px 30px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.pricing-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-4px);
}

/* 主推款高光 */
.pricing-card.flagship {
  border: 1px solid var(--border-focus);
  background: var(--bg-elevated);
}

.flagship-label {
  position: absolute;
  top: -12px;
  left: 28px;
  background: var(--text-pure);
  color: var(--text-inverse);
  font-size: 0.72rem;
  font-weight: 700;
  padding: 2px 10px;
  border-radius: 4px;
  text-transform: uppercase;
}

.plan-header {
  margin-bottom: 20px;
}

.plan-name {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-pure);
  letter-spacing: -0.02em;
  margin-bottom: 6px;
}

.plan-desc {
  font-size: 0.86rem;
  color: var(--text-muted);
}

.plan-price-box {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin: 18px 0;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-hairline);
}

.plan-currency {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-pure);
}

.plan-number {
  font-size: 2.8rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1;
  color: var(--text-pure);
}

.plan-cycle {
  font-size: 0.88rem;
  color: var(--text-muted);
}

.plan-features-list {
  list-style: none;
  margin-bottom: 30px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  flex-grow: 1;
}

.plan-features-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.feature-check-mono {
  font-size: 0.85rem;
  color: var(--text-pure);
  font-weight: 700;
  width: 14px;
  text-align: center;
}

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

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-hairline);
  border-radius: 12px;
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  transition: border-color 0.2s ease;
}

.review-card:hover {
  border-color: var(--border-focus);
}

.review-score {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.review-content {
  font-size: 0.94rem;
  line-height: 1.65;
  color: var(--text-secondary);
  margin-bottom: 20px;
  flex-grow: 1;
}

.review-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-top: 14px;
  border-top: 1px solid var(--border-hairline);
}

.reviewer-symbol {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text-pure);
}

.reviewer-name {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-pure);
}

.reviewer-role {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* ==========================================================================
   常见问题解答 (FAQ)
   ========================================================================== */
.faq-wrap {
  max-width: 860px;
  margin: 0 auto;
  border-top: 1px solid var(--border-hairline);
}

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

.faq-question {
  width: 100%;
  padding: 22px 4px;
  text-align: left;
  background: none;
  border: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  cursor: pointer;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-pure);
  outline: none;
}

.faq-indicator {
  font-size: 1.2rem;
  font-family: ui-monospace, monospace;
  color: var(--text-muted);
  transition: transform 0.25s ease;
}

.faq-item.active .faq-indicator {
  transform: rotate(45deg);
  color: var(--text-pure);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0, 1, 0, 1), padding 0.3s ease;
  padding: 0 4px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 400px;
  padding: 0 4px 22px;
}

/* ==========================================================================
   推荐资讯 (News / Insights) 专用卡片
   ========================================================================== */
.insights-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.insight-card {
  background: var(--bg-card);
  border: 1px solid var(--border-hairline);
  border-radius: 12px;
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  transition: all 0.2s ease;
}

.insight-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-2px);
}

.insight-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

.insight-title {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-pure);
  margin-bottom: 12px;
  line-height: 1.35;
}

.insight-excerpt {
  font-size: 0.94rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 24px;
  flex-grow: 1;
}

/* ==========================================================================
   二级合规页面通用样式 (About, Terms, Privacy, Sitemap)
   ========================================================================== */
.page-container {
  padding: 70px 0 100px;
}

.page-header {
  max-width: 840px;
  margin: 0 auto 50px;
  text-align: center;
}

.page-title {
  font-size: clamp(1.6rem, 3.5vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-pure);
  margin-bottom: 14px;
}

.page-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
}

.monolith-card {
  background: var(--bg-card);
  border: 1px solid var(--border-hairline);
  border-radius: 14px;
  padding: 44px 40px;
  max-width: 900px;
  margin: 0 auto;
}

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

.monolith-section:last-child {
  margin-bottom: 0;
}

.monolith-section h2 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-pure);
  margin-bottom: 14px;
  letter-spacing: -0.02em;
}

.monolith-section p {
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 12px;
  font-size: 0.96rem;
}

.monolith-section ul {
  padding-left: 20px;
  color: var(--text-secondary);
  line-height: 1.75;
  font-size: 0.96rem;
}

.monolith-section ul li {
  margin-bottom: 8px;
}

.monolith-quote {
  border-left: 2px solid var(--text-pure);
  padding: 14px 18px;
  background: var(--bg-surface);
  border-radius: 0 8px 8px 0;
  margin: 18px 0;
  font-size: 0.92rem;
  color: var(--text-secondary);
}

/* ==========================================================================
   深度科普 SEO 文章排版规范 (Articles, TOC, FAQ, Related Reading)
   ========================================================================== */
.article-wrap {
  max-width: 880px;
  margin: 0 auto;
}

.article-header {
  margin-bottom: 36px;
  border-bottom: 1px solid var(--border-hairline);
  padding-bottom: 28px;
}

.article-meta-bar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

.article-headline {
  font-size: clamp(1.8rem, 3.5vw, 2.5rem);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.03em;
  color: var(--text-pure);
  margin-bottom: 18px;
}

.article-lead {
  font-size: 1.08rem;
  line-height: 1.7;
  color: var(--text-secondary);
  font-weight: 400;
}

/* 目录 (Table of Contents) */
.toc-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: 12px;
  padding: 24px 28px;
  margin: 32px 0 40px;
}

.toc-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-pure);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.toc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-left: 0;
}

.toc-list li a {
  font-size: 0.92rem;
  color: var(--text-muted);
  transition: color 0.2s ease, transform 0.2s ease;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.toc-list li a:hover {
  color: var(--text-pure);
  transform: translateX(3px);
}

.toc-sublist {
  list-style: none;
  padding-left: 20px;
  margin-top: 6px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

/* 文章正文正规化排版 */
.article-body {
  color: var(--text-secondary);
  font-size: 1.02rem;
  line-height: 1.85;
}

.article-body h2 {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text-pure);
  margin: 48px 0 18px;
  letter-spacing: -0.02em;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-hairline);
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-pure);
  margin: 28px 0 12px;
  letter-spacing: -0.01em;
}

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

.article-body ul, .article-body ol {
  margin: 16px 0 24px 24px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.article-body li strong {
  color: var(--text-pure);
}

.article-body blockquote {
  border-left: 3px solid var(--text-pure);
  padding: 16px 22px;
  background: var(--bg-surface);
  border-radius: 0 10px 10px 0;
  margin: 24px 0;
  color: var(--text-secondary);
  font-style: normal;
}

.article-body a {
  color: var(--text-pure);
  text-decoration: underline;
  text-underline-offset: 3px;
  font-weight: 600;
  transition: opacity 0.2s ease;
}

.article-body a:hover {
  opacity: 0.8;
}

/* 规范化表格 */
.table-scroll {
  overflow-x: auto;
  margin: 28px 0;
  border: 1px solid var(--border-hairline);
  border-radius: 10px;
}

.article-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9rem;
}

.article-table th {
  background: var(--bg-surface);
  padding: 14px 18px;
  color: var(--text-pure);
  font-weight: 700;
  border-bottom: 1px solid var(--border-hairline);
  white-space: nowrap;
}

.article-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-hairline);
  color: var(--text-secondary);
}

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

.article-table tr:hover td {
  background: var(--bg-surface);
}

/* 代码高亮块 */
.code-block {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: 10px;
  padding: 18px 22px;
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.88rem;
  line-height: 1.6;
  margin: 24px 0;
  overflow-x: auto;
  color: var(--text-pure);
}

/* FAQ 模块规范 */
.article-faq {
  margin: 50px 0;
  padding: 36px 30px;
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: 14px;
}

.article-faq h2 {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-pure);
  margin-bottom: 24px;
  padding-bottom: 0;
  border-bottom: none;
}

.faq-qa-item {
  margin-bottom: 22px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--border-hairline);
}

.faq-qa-item:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.faq-qa-q {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-pure);
  margin-bottom: 8px;
}

.faq-qa-a {
  font-size: 0.94rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* 相关阅读 (Related Reading) */
.related-reading-box {
  margin: 50px 0 30px;
  padding-top: 36px;
  border-top: 1px solid var(--border-hairline);
}

.related-reading-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-pure);
  margin-bottom: 20px;
}

.related-links-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.related-link-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: 10px;
  padding: 18px 20px;
  display: flex;
  flex-direction: column;
  transition: all 0.2s ease;
  text-decoration: none !important;
}

.related-link-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-2px);
}

.related-link-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-pure);
  line-height: 1.4;
  margin-bottom: 6px;
}

.related-link-meta {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* 文章末尾专属转化呼吁 */
.article-cta-box {
  background: var(--bg-card);
  border: 1px solid var(--border-hairline);
  border-radius: 14px;
  padding: 36px 30px;
  margin: 40px 0;
  text-align: center;
}

.article-cta-box h3 {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-pure);
  margin-bottom: 10px;
}

.article-cta-box p {
  color: var(--text-muted);
  font-size: 0.95rem;
  max-width: 620px;
  margin: 0 auto 22px;
}

/* ==========================================================================
   页脚 (Footer) - 严格只保留四个独立页面标题
   ========================================================================== */
.site-footer {
  background: var(--bg-void);
  border-top: 1px solid var(--border-hairline);
  padding: 44px 0 36px;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 36px;
  margin-bottom: 26px;
}

.footer-link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.2s ease;
}

.footer-link:hover {
  color: var(--text-pure);
}

.footer-copyright {
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-faint);
  border-top: 1px solid var(--border-hairline);
  padding-top: 22px;
}

/* ==========================================================================
   移动端响应式适配 (@media queries)
   ========================================================================== */
@media (max-width: 1024px) {
  .features-grid,
  .pricing-grid,
  .reviews-grid,
  .insights-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-container {
    height: 60px;
  }

  .mobile-menu-btn {
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .nav-links {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--bg-void);
    flex-direction: column;
    padding: 24px;
    gap: 16px;
    border-bottom: 1px solid var(--border-hairline);
    transform: translateY(-150%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.3s ease;
    z-index: 999;
  }

  .nav-links.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-links a {
    font-size: 1rem;
    width: 100%;
    text-align: center;
    padding: 8px 0;
  }

  .nav-actions .btn {
    display: none;
  }

  .hero-section {
    padding: 60px 0 50px;
  }

  .hero-title {
    font-size: clamp(0.9rem, 4.2vw, 1.85rem);
    white-space: nowrap;
    text-wrap: nowrap;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .hero-specs-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }

  .hero-actions {
    flex-direction: column;
    width: 100%;
  }

  .hero-actions .btn {
    width: 100%;
    min-height: 48px;
  }

  .features-grid,
  .showcase-grid,
  .pricing-grid,
  .reviews-grid,
  .insights-grid,
  .monochrome-matrix {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .feature-card,
  .showcase-card,
  .pricing-card,
  .monolith-card {
    padding: 24px 20px;
  }

  .section {
    padding: 65px 0;
  }

  .section-title {
    font-size: 1.85rem;
  }

  .footer-nav {
    flex-direction: column;
    gap: 16px;
  }
}