/* ==========================================================================
   IPLC.APP - 瑞士理性主义极简工程学样式表 (Swiss-Rationalist Minimalist UI)
   设计理念：Pure Functionalist Palette · 1px Datum Lines · Architectural Grid
   ========================================================================== */

:root {
  /* 瑞士理性主义调色板 (白天模式 Stark Optical White & Pure Carbon Ink) */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f8fb;
  --bg-card: #ffffff;
  --bg-card-subtle: #f5f5f9;
  --bg-glass: rgba(255, 255, 255, 0.92);
  --bg-hover: #f0f0f5;
  
  --text-primary: #111118;
  --text-secondary: #4a4a58;
  --text-muted: #78788a;
  
  --border-color: #e4e4ed;
  --border-darker: #c8c8d8;
  --border-focus: #0051ff;
  
  /* 单一纯净签名色：外科级传输蓝 (Surgical Transit Blue) */
  --accent-primary: #0051ff;
  --accent-hover: #003ece;
  --accent-light: #edf2ff;
  --accent-glow: rgba(0, 81, 255, 0.16);
  
  --tag-bg: #f0f2f8;
  --tag-text: #1a1a24;
  
  --datum-line: rgba(17, 17, 24, 0.08);
  --grid-line: rgba(17, 17, 24, 0.04);
  
  --mono-font: ui-monospace, "SF Mono", "Roboto Mono", "Cascadia Code", Menlo, Consolas, monospace;
  --sans-font: -apple-system, BlinkMacSystemFont, "Helvetica Neue", "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  
  --radius-xs: 2px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-full: 9999px;
  
  --transition-fast: 0.18s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-smooth: 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

[data-theme="dark"] {
  /* 瑞士理性主义调色板 (暗黑模式 Stark Carbon & Engineering Blue) */
  --bg-primary: #08080c;
  --bg-secondary: #0e0e14;
  --bg-card: #111118;
  --bg-card-subtle: #161622;
  --bg-glass: rgba(8, 8, 12, 0.92);
  --bg-hover: #1a1a26;
  
  --text-primary: #f4f4f8;
  --text-secondary: #a2a2b4;
  --text-muted: #6a6a7c;
  
  --border-color: #1e1e2c;
  --border-darker: #2d2d40;
  --border-focus: #0051ff;
  
  --accent-primary: #2968ff;
  --accent-hover: #4d82ff;
  --accent-light: rgba(41, 104, 255, 0.12);
  --accent-glow: rgba(41, 104, 255, 0.28);
  
  --tag-bg: #181824;
  --tag-text: #d8d8e6;
  
  --datum-line: rgba(255, 255, 255, 0.08);
  --grid-line: rgba(255, 255, 255, 0.03);
}

/* 基础重置与排版规范 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-family: var(--sans-font);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color 0.3s ease, color 0.3s ease;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  background-image: 
    linear-gradient(to right, var(--grid-line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--grid-line) 1px, transparent 1px);
  background-size: 80px 80px;
}

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

ul {
  list-style: none;
}

/* 容器与基准线系统 */
.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 32px;
  position: relative;
}

.datum-line {
  width: 100%;
  height: 1px;
  background: var(--datum-line);
  margin: 0;
}

/* 顶部导航栏 (Swiss Minimalist Header) */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition-fast);
}

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

/* LOGO 持续平滑转动动效 */
@keyframes logoSpin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

.brand-logo-img {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  object-fit: contain;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.12);
  display: block;
  transform-origin: 50% 50%;
  animation: logoSpin 8s linear infinite;
  will-change: transform;
  transition: box-shadow 0.3s ease, filter 0.3s ease;
}

.brand-logo:hover .brand-logo-img {
  animation-duration: 2.2s;
  box-shadow: 0 0 16px var(--accent-glow);
}

@media (prefers-reduced-motion: reduce) {
  .brand-logo-img {
    animation: none;
  }
}

.brand-logo-text {
  font-size: 1.32rem;
  font-weight: 800;
  letter-spacing: 0.8px;
  color: var(--text-primary);
  font-family: var(--sans-font);
  transition: color 0.3s ease;
}

[data-theme="dark"] .brand-logo-text {
  color: #ffffff;
  text-shadow: 0 0 12px rgba(41, 104, 255, 0.4);
}

/* 导航链接 */
.nav-links {
  display: flex;
  align-items: center;
  gap: 22px;
}

.nav-item {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-secondary);
  padding: 6px 4px;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-item:hover, .nav-item.active {
  color: var(--accent-primary);
}

.nav-item-badge {
  font-family: var(--mono-font);
  font-size: 0.72rem;
  padding: 2px 6px;
  background: var(--accent-light);
  color: var(--accent-primary);
  border-radius: var(--radius-xs);
  margin-left: 4px;
  vertical-align: 1px;
}

/* 右侧操作区 */
.header-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

/* 瑞士工学昼夜模式切换按钮 (精致透明质感，无粗糙emoji) */
.theme-toggle-btn {
  position: relative;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-fast);
  outline: none;
}

.theme-toggle-btn:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.theme-icon {
  width: 18px;
  height: 18px;
  position: absolute;
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.25s ease;
}

.theme-icon-sun {
  opacity: 1;
  transform: rotate(0) scale(1);
}

.theme-icon-moon {
  opacity: 0;
  transform: rotate(90deg) scale(0.5);
}

[data-theme="dark"] .theme-icon-sun {
  opacity: 0;
  transform: rotate(-90deg) scale(0.5);
}

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

.mobile-menu-btn {
  display: none;
  background: none;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  cursor: pointer;
  padding: 6px;
}

/* 工学按钮规范 (CTA Buttons) */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 9px 20px;
  font-size: 0.92rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  white-space: nowrap;
  transition: var(--transition-fast);
  text-decoration: none;
  font-family: var(--sans-font);
}

.btn-primary {
  background: var(--accent-primary);
  color: #ffffff !important;
  border-color: var(--accent-primary);
}

.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  box-shadow: 0 4px 16px var(--accent-glow);
}

.btn-secondary {
  background: transparent;
  border-color: var(--border-color);
  color: var(--text-primary);
}

.btn-secondary:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  background: var(--bg-hover);
}

.btn-lg {
  padding: 13px 28px;
  font-size: 1rem;
}

.btn-block {
  width: 100%;
}

/* 瑞士工学标签 */
.swiss-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  font-family: var(--mono-font);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  background: var(--tag-bg);
  color: var(--tag-text);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xs);
}

.swiss-tag-accent {
  background: var(--accent-light);
  color: var(--accent-primary);
  border-color: rgba(0, 81, 255, 0.25);
}

/* ==========================================================================
   主视觉区 (Hero Section) - 纯粹理性建筑式结构
   ========================================================================== */
.hero-section {
  padding: 80px 0 60px;
  position: relative;
}

.hero-meta-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
  font-family: var(--mono-font);
  font-size: 0.8rem;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 12px;
}

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

.status-pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #10b981;
  box-shadow: 0 0 8px #10b981;
}

.hero-title {
  font-size: 3.6rem;
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -1.8px;
  margin-bottom: 24px;
  color: var(--text-primary);
  max-width: 1000px;
}

.hero-title .brand-name-highlight {
  color: var(--accent-primary);
  display: inline-block;
}

.hero-title-en {
  display: block;
  font-family: var(--mono-font);
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  color: var(--text-muted);
  margin-top: 10px;
  text-transform: uppercase;
}

.hero-desc {
  font-size: 1.2rem;
  line-height: 1.7;
  color: var(--text-secondary);
  max-width: 760px;
  margin-bottom: 36px;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

/* 精密卡尺微交互：点对点专线仪表盘 (Point-to-Point Caliper Readout) */
.route-caliper-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  margin-top: 20px;
}

.caliper-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-color);
}

.caliper-title {
  font-size: 0.92rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.caliper-nav {
  display: flex;
  gap: 8px;
}

.route-tab-btn {
  font-family: var(--mono-font);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 5px 12px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xs);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition-fast);
}

.route-tab-btn.active, .route-tab-btn:hover {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
}

.caliper-display {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 20px;
  padding: 18px 0 10px;
}

.node-endpoint {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.endpoint-code {
  font-family: var(--mono-font);
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
}

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

.transit-hairline {
  position: relative;
  height: 2px;
  background: var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 220px;
}

.hairline-fill {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 100%;
  background: var(--accent-primary);
}

.hairline-beacon {
  position: absolute;
  width: 8px;
  height: 8px;
  background: var(--accent-primary);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--accent-primary);
  animation: beaconSlide 2.5s ease-in-out infinite;
}

@keyframes beaconSlide {
  0% { left: 0%; opacity: 0.4; }
  50% { left: 50%; opacity: 1; transform: scale(1.2); }
  100% { left: 100%; opacity: 0.4; }
}

.caliper-readout-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px dashed var(--border-color);
}

.caliper-metric {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.metric-label {
  font-family: var(--mono-font);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
}

.metric-value {
  font-family: var(--mono-font);
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--accent-primary);
}

/* ==========================================================================
   通用章节结构
   ========================================================================== */
.section {
  padding: 80px 0;
  border-top: 1px solid var(--border-color);
}

.section-header {
  margin-bottom: 48px;
}

.section-label {
  font-family: var(--mono-font);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--accent-primary);
  margin-bottom: 8px;
  display: block;
}

.section-title {
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.8px;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 680px;
  line-height: 1.6;
}

/* 产品核心优势 (3个图文卡片) - 瑞士理性工学卡片 */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  transition: var(--transition-fast);
  display: flex;
  flex-direction: column;
}

.feature-card:hover {
  border-color: var(--accent-primary);
  box-shadow: 0 4px 20px var(--accent-glow);
}

.feature-num {
  font-family: var(--mono-font);
  font-size: 0.85rem;
  font-weight: 800;
  color: var(--accent-primary);
  margin-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 8px;
}

.feature-card-title {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.feature-card-text {
  font-size: 0.94rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* 流媒体与 AI 支持图卡专区 */
.media-ai-container {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.showcase-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 36px 32px;
  transition: var(--transition-fast);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.showcase-card:hover {
  border-color: var(--accent-primary);
}

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

.showcase-top-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.showcase-title {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.showcase-desc {
  font-size: 0.96rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

.service-tags-wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 24px 0;
}

.service-chip {
  padding: 6px 12px;
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xs);
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text-secondary);
  font-family: var(--sans-font);
}

.feature-bullets {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.feature-bullet-item {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  font-size: 0.92rem;
  color: var(--text-secondary);
}

.bullet-check-icon {
  color: var(--accent-primary);
  flex-shrink: 0;
  margin-top: 3px;
}

/* ==========================================================================
   套餐价格对比表 (真实参考价 + 零延迟机械周期填充切换)
   ========================================================================== */
.pricing-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 40px;
}

.duration-selector {
  display: inline-flex;
  padding: 4px;
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  gap: 4px;
}

.duration-btn {
  font-family: var(--mono-font);
  font-size: 0.85rem;
  font-weight: 700;
  padding: 8px 18px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: var(--radius-xs);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.duration-btn.active {
  background: var(--accent-primary);
  color: #ffffff;
}

.discount-pill {
  font-size: 0.72rem;
  padding: 1px 6px;
  background: rgba(255, 255, 255, 0.25);
  border-radius: var(--radius-xs);
  margin-left: 4px;
}

.duration-btn:not(.active) .discount-pill {
  background: var(--accent-light);
  color: var(--accent-primary);
}

.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-color);
  border-radius: var(--radius-md);
  padding: 36px 30px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition-fast);
}

.pricing-card:hover {
  border-color: var(--border-darker);
}

.pricing-card-featured {
  border: 2px solid var(--accent-primary);
}

.featured-ribbon {
  position: absolute;
  top: -12px;
  left: 24px;
  background: var(--accent-primary);
  color: #ffffff;
  font-family: var(--mono-font);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  padding: 2px 10px;
  border-radius: var(--radius-xs);
}

.pricing-card-header {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 20px;
  margin-bottom: 24px;
}

.pricing-plan-name {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 4px;
}

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

.pricing-cost-row {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-top: 16px;
}

.pricing-currency {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent-primary);
}

.pricing-amount {
  font-family: var(--mono-font);
  font-size: 2.8rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1;
}

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

.pricing-features-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 32px;
  flex-grow: 1;
}

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

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

.testimonial-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 30px 26px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.testimonial-meta {
  font-family: var(--mono-font);
  font-size: 0.78rem;
  color: var(--accent-primary);
  margin-bottom: 14px;
}

.testimonial-text {
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.testimonial-user {
  display: flex;
  align-items: center;
  gap: 12px;
  border-top: 1px solid var(--border-color);
  padding-top: 16px;
}

.user-avatar-char {
  width: 36px;
  height: 36px;
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-family: var(--mono-font);
  font-weight: 800;
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-primary);
}

.user-name {
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--text-primary);
}

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

/* 常见问题解答 (FAQ) */
.faq-container {
  max-width: 840px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: var(--transition-fast);
}

.faq-item.active {
  border-color: var(--border-darker);
}

.faq-question-btn {
  width: 100%;
  padding: 20px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: none;
  border: none;
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--text-primary);
  cursor: pointer;
  text-align: left;
  transition: color var(--transition-fast);
}

.faq-question-btn:hover {
  color: var(--accent-primary);
}

.faq-icon-arrow {
  width: 18px;
  height: 18px;
  transition: transform 0.3s ease;
  flex-shrink: 0;
  color: var(--text-muted);
}

.faq-item.active .faq-icon-arrow {
  transform: rotate(180deg);
  color: var(--accent-primary);
}

.faq-answer-panel {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0, 1, 0, 1);
  padding: 0 24px;
}

.faq-item.active .faq-answer-panel {
  max-height: 600px;
  padding-bottom: 20px;
  transition: max-height 0.35s ease-in-out;
}

.faq-answer-content {
  font-size: 0.94rem;
  line-height: 1.75;
  color: var(--text-secondary);
}

/* 页脚 (Footer) - 严格保留四个标题 */
.footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border-color);
  padding: 48px 0 32px;
  margin-top: auto;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 36px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.footer-link {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.footer-link:hover {
  color: var(--accent-primary);
}

.footer-bottom {
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  padding-top: 24px;
}

/* 资讯与独立子页专属样式 (Articles & Insights) */
.page-hero {
  padding: 60px 0 36px;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-card-subtle);
}

.page-title {
  font-size: 2.3rem;
  font-weight: 800;
  letter-spacing: -0.6px;
  margin-top: 8px;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.page-lead {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 720px;
}

.content-article {
  max-width: 860px;
  margin: 48px auto 80px;
  padding: 0 24px;
}

.content-block {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px 30px;
  margin-bottom: 24px;
}

.content-block h2 {
  font-size: 1.35rem;
  font-weight: 800;
  margin-bottom: 14px;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
}

.content-block p {
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 14px;
}

.content-block p:last-child {
  margin-bottom: 0;
}

.content-block ul {
  list-style: square;
  padding-left: 22px;
  margin-bottom: 14px;
  color: var(--text-secondary);
  line-height: 1.8;
}

/* 资讯文章列表卡片 (Insights / Articles) */
.insights-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin: 40px 0;
}

.insight-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 30px;
  transition: var(--transition-fast);
  display: flex;
  flex-direction: column;
}

.insight-card:hover {
  border-color: var(--accent-primary);
}

.insight-date {
  font-family: var(--mono-font);
  font-size: 0.78rem;
  color: var(--accent-primary);
  margin-bottom: 8px;
}

.insight-title {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.insight-summary {
  font-size: 0.94rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ==========================================================================
   深度科普 SEO 文章专属排版样式 (In-Depth Technical SEO Article Layout)
   ========================================================================== */
.article-wrapper {
  max-width: 900px;
  margin: 40px auto 80px;
  padding: 0 24px;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--mono-font);
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.breadcrumb a:hover {
  color: var(--accent-primary);
  text-decoration: underline;
}

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

.article-title-main {
  font-size: 2.4rem;
  font-weight: 900;
  line-height: 1.25;
  letter-spacing: -0.8px;
  color: var(--text-primary);
  margin: 16px 0;
}

.article-meta-bar {
  display: flex;
  align-items: center;
  gap: 18px;
  font-family: var(--mono-font);
  font-size: 0.82rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}

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

/* 目录框 (Table of Contents) */
.toc-box {
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--accent-primary);
  border-radius: var(--radius-sm);
  padding: 24px 28px;
  margin: 32px 0 44px;
}

.toc-title {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-left: 20px;
  list-style: decimal;
}

.toc-list li a {
  font-size: 0.94rem;
  color: var(--text-secondary);
  font-weight: 600;
}

.toc-list li a:hover {
  color: var(--accent-primary);
  text-decoration: underline;
}

/* 文章正文 (Article Body) */
.article-body {
  font-size: 1.05rem;
  line-height: 1.85;
  color: var(--text-secondary);
}

.article-body h2 {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text-primary);
  margin: 48px 0 18px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-color);
  scroll-margin-top: 90px;
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 750;
  color: var(--text-primary);
  margin: 30px 0 14px;
  scroll-margin-top: 90px;
}

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

.article-body ul, .article-body ol {
  margin: 16px 0 24px 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

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

.article-body a {
  color: var(--accent-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.article-body a:hover {
  color: var(--accent-hover);
}

.article-body blockquote {
  border-left: 3px solid var(--accent-primary);
  background: var(--bg-card-subtle);
  padding: 16px 20px;
  margin: 24px 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-style: italic;
  color: var(--text-secondary);
}

.article-body code {
  font-family: var(--mono-font);
  font-size: 0.88rem;
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-color);
  padding: 2px 6px;
  border-radius: var(--radius-xs);
  color: var(--accent-primary);
}

.article-body pre {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 18px;
  overflow-x: auto;
  margin: 20px 0;
  font-family: var(--mono-font);
  font-size: 0.88rem;
  line-height: 1.6;
}

/* 文章数据对比表格 */
.article-table-wrap {
  overflow-x: auto;
  margin: 28px 0;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
}

.article-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}

.article-table th {
  background: var(--bg-card-subtle);
  padding: 12px 16px;
  text-align: left;
  font-weight: 750;
  color: var(--text-primary);
  border-bottom: 1px solid var(--border-color);
}

.article-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-secondary);
}

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

/* 文章内嵌 CTA 推荐卡片 */
.article-cta-box {
  background: var(--bg-card);
  border: 2px solid var(--accent-primary);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  margin: 48px 0;
  text-align: center;
}

.article-cta-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.article-cta-desc {
  font-size: 0.96rem;
  color: var(--text-secondary);
  max-width: 620px;
  margin: 0 auto 20px;
}

/* 文章 FAQ 问答板块 */
.article-faq-section {
  margin: 50px 0;
  padding-top: 36px;
  border-top: 1px solid var(--border-color);
}

.article-faq-title {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 24px;
}

.article-faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 20px 24px;
  margin-bottom: 14px;
}

.article-faq-q {
  font-size: 1.05rem;
  font-weight: 750;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.article-faq-a {
  font-size: 0.94rem;
  line-height: 1.75;
  color: var(--text-secondary);
}

/* 相关阅读推荐 (Related Articles) */
.related-posts-section {
  margin: 60px 0 20px;
  padding-top: 36px;
  border-top: 1px solid var(--border-color);
}

.related-posts-title {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 20px;
}

.related-posts-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.related-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 20px;
  transition: var(--transition-fast);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

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

.related-card-title {
  font-size: 0.98rem;
  font-weight: 750;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.45;
}

.related-card-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
}

@media (max-width: 768px) {
  .related-posts-grid {
    grid-template-columns: 1fr;
  }
  .article-title-main {
    font-size: 1.8rem;
  }
}

/* 响应式适配 (@media) */
@media (max-width: 992px) {
  .hero-title {
    font-size: 2.8rem;
  }
  .features-grid {
    grid-template-columns: 1fr;
  }
  .media-ai-container {
    grid-template-columns: 1fr;
  }
  .pricing-grid {
    grid-template-columns: 1fr;
    max-width: 480px;
    margin: 0 auto;
  }
  .testimonials-grid {
    grid-template-columns: 1fr;
    max-width: 500px;
    margin: 0 auto;
  }
  .caliper-display {
    grid-template-columns: 1fr;
    gap: 12px;
    text-align: center;
  }
  .transit-hairline {
    min-width: 100%;
  }
  .caliper-readout-strip {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 20px;
  }
  .header-inner {
    height: 60px;
  }
  .mobile-menu-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }
  .nav-links {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    padding: 20px 24px;
    gap: 14px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
    transform: translateY(-150%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.25s ease, opacity 0.25s ease;
    z-index: 99;
  }
  .nav-links.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .hero-section {
    padding: 50px 0 36px;
  }
  .hero-title {
    font-size: 2.1rem;
    letter-spacing: -0.6px;
  }
  .hero-title-en {
    font-size: 0.95rem;
  }
  .hero-desc {
    font-size: 1rem;
  }
  .section {
    padding: 50px 0;
  }
  .section-title {
    font-size: 1.7rem;
  }
  .footer-nav {
    flex-direction: column;
    gap: 16px;
  }
  .btn {
    min-height: 48px;
    padding: 12px 24px;
  }
  .caliper-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
  .caliper-nav {
    flex-wrap: wrap;
  }
}