/* ==========================================================================
   肯の机 (KENDEJI.BABY) - 核心样式表
   Stealth Neutral-Charcoal Dark Workspace UI Design
   极简纯原生 CSS · 零第三方依赖 · 秒开加载 · 昼夜无缝切换 · 机械阻尼反馈
   ========================================================================== */

:root {
  /* 白天模式 (Light Workspace) */
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --bg-card: #ffffff;
  --bg-card-hover: #f8fafc;
  --bg-glass: rgba(255, 255, 255, 0.88);
  --border-color: #e2e8f0;
  --border-light: #edf2f7;

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --text-inverse: #ffffff;

  --status-emerald: #10b981;
  --status-emerald-glow: rgba(16, 185, 129, 0.4);
  --status-amber: #f59e0b;
  --status-blue: #3b82f6;

  --brand-primary: #e11d48;
  --brand-primary-hover: #be123c;
  --brand-secondary: #6366f1;
  --brand-gradient: linear-gradient(135deg, #e11d48 0%, #be123c 60%, #4338ca 100%);
  --brand-glow: rgba(225, 29, 72, 0.2);

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.07), 0 2px 4px -2px rgba(15, 23, 42, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.08), 0 4px 6px -4px rgba(15, 23, 42, 0.04);
  --shadow-xl: 0 20px 25px -5px rgba(15, 23, 42, 0.1), 0 8px 10px -6px rgba(15, 23, 42, 0.06);

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;

  --nav-height: 72px;
  --max-width: 1240px;
  --transition: all 0.22s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==========================================================================
   深邃暗黑夜间工作台模式 (Deep Nocturnal Focus Palette)
   Graphite: #121316 | Slate Card: #1a1d24 | LED Emerald: #10b981
   ========================================================================== */
[data-theme="dark"] {
  --bg-primary: #121316;       /* dark neutral graphite */
  --bg-secondary: #171920;
  --bg-tertiary: #1f232c;
  --bg-card: #1a1d24;          /* slate card container */
  --bg-card-hover: #222630;
  --bg-glass: rgba(18, 19, 22, 0.88);
  --border-color: #262a34;
  --border-light: #21252e;

  --text-primary: #f8fafc;     /* crisp cold-white typography */
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-inverse: #121316;

  --status-emerald: #10b981;   /* precision status LED emerald */
  --status-emerald-glow: rgba(16, 185, 129, 0.5);
  --status-amber: #fbbf24;
  --status-blue: #60a5fa;

  --brand-primary: #f43f5e;
  --brand-primary-hover: #fb7185;
  --brand-secondary: #818cf8;
  --brand-gradient: linear-gradient(135deg, #f43f5e 0%, #fb7185 50%, #6366f1 100%);
  --brand-glow: rgba(244, 63, 94, 0.28);

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.6);
  --shadow-md: 0 4px 10px -1px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 10px 20px -3px rgba(0, 0, 0, 0.6);
  --shadow-xl: 0 20px 30px -5px rgba(0, 0, 0, 0.7);
}

/* ==========================================================================
   全局重置与排版
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

html {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 20px);
  font-size: 16px;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  transition: background-color 0.35s ease, color 0.35s ease;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

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

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

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ==========================================================================
   机械按键阻尼动画与状态 (Weighted Mechanical Dampening)
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 11px 22px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  white-space: nowrap;
  line-height: 1.2;
  user-select: none;
  transition: transform 0.12s cubic-bezier(0.2, 0.8, 0.4, 1), box-shadow 0.12s ease, background 0.2s ease, border-color 0.2s ease, color 0.2s ease;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2), inset 0 1px 0 rgba(255, 255, 255, 0.12);
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.28), inset 0 1px 0 rgba(255, 255, 255, 0.2);
}

/* 机械加重下压阻尼触感 */
.btn:active {
  transform: translateY(2px) scale(0.985);
  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.4), inset 0 2px 4px rgba(0, 0, 0, 0.3);
}

.btn-primary {
  background: var(--brand-gradient);
  color: #ffffff !important;
  box-shadow: 0 4px 14px var(--brand-glow), inset 0 1px 0 rgba(255, 255, 255, 0.25);
}

.btn-primary:hover {
  box-shadow: 0 8px 22px var(--brand-glow), inset 0 1px 0 rgba(255, 255, 255, 0.35);
  opacity: 0.96;
}

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

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

.btn-emerald {
  background: var(--status-emerald);
  color: #ffffff !important;
  box-shadow: 0 4px 14px var(--status-emerald-glow);
}

.btn-emerald:hover {
  background: #059669;
  box-shadow: 0 6px 20px var(--status-emerald-glow);
}

.btn-lg {
  padding: 13px 28px;
  font-size: 1.02rem;
  min-height: 48px;
}

.btn-block {
  width: 100%;
}

/* ==========================================================================
   精密状态荧光 LED 呼吸灯 (Miniature Phosphor LED Respiration Glow)
   ========================================================================== */
@keyframes phosphor-respiration {
  0%, 100% {
    opacity: 0.75;
    box-shadow: 0 0 5px var(--status-emerald), inset 0 0 2px #ffffff;
    transform: scale(1);
  }
  50% {
    opacity: 1;
    box-shadow: 0 0 12px var(--status-emerald), 0 0 22px rgba(16, 185, 129, 0.65), inset 0 0 3px #ffffff;
    transform: scale(1.15);
  }
}

.led-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--status-emerald);
  box-shadow: 0 0 6px var(--status-emerald-glow);
  display: inline-block;
  flex-shrink: 0;
  transition: var(--transition);
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  background: rgba(16, 185, 129, 0.12);
  color: var(--status-emerald);
  border: 1px solid rgba(16, 185, 129, 0.25);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

/* 悬停卡片触发真实荧光 LED 呼吸 */
.node-cluster-card:hover .led-dot,
.status-pill:hover .led-dot,
.telemetry-box:hover .led-dot {
  animation: phosphor-respiration 1.6s infinite ease-in-out;
}

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

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.brand-logo-img {
  height: 42px;
  width: auto;
  display: block;
  object-fit: contain;
  transition: var(--transition);
}

.brand-logo:hover .brand-logo-img {
  transform: scale(1.02);
}

[data-theme="dark"] .brand-logo-img {
  filter: drop-shadow(0 2px 10px rgba(129, 140, 248, 0.3));
}

.brand-badge {
  font-size: 0.68rem;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: var(--radius-full);
  background: rgba(225, 29, 72, 0.12);
  color: var(--brand-primary);
  margin-left: 2px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 20px;
  list-style: none;
}

.nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 6px 2px;
  transition: var(--transition);
}

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

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--brand-primary);
  transition: var(--transition);
}

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

.nav-badge-new {
  font-size: 0.65rem;
  padding: 1px 6px;
  border-radius: var(--radius-full);
  background: rgba(16, 185, 129, 0.18);
  color: var(--status-emerald);
  font-weight: 700;
  margin-left: 4px;
}

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

/* 昼夜模式切换按钮 */
.theme-toggle-btn {
  background: rgba(125, 125, 125, 0.08);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  cursor: pointer;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.theme-toggle-btn:hover {
  background: rgba(125, 125, 125, 0.16);
  border-color: var(--text-secondary);
  transform: scale(1.04);
}

.theme-toggle-btn svg {
  width: 20px;
  height: 20px;
  position: absolute;
  transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease;
}

.theme-icon-sun {
  opacity: 0;
  transform: rotate(90deg) scale(0.6);
}

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

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

[data-theme="dark"] .theme-icon-moon {
  opacity: 0;
  transform: rotate(-90deg) scale(0.6);
}

/* ==========================================================================
   主视觉区 (Hero Section)
   ========================================================================== */
.hero-section {
  padding: 68px 0 54px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero-glow-bg {
  position: absolute;
  top: -120px;
  left: 50%;
  transform: translateX(-50%);
  width: 860px;
  height: 460px;
  background: radial-gradient(circle, var(--brand-glow) 0%, rgba(99, 102, 241, 0.08) 50%, transparent 75%);
  filter: blur(70px);
  pointer-events: none;
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 900px;
  margin: 0 auto;
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.hero-title {
  font-size: 3.25rem;
  font-weight: 900;
  letter-spacing: -1.2px;
  line-height: 1.22;
  margin-bottom: 20px;
  color: var(--text-primary);
}

.gradient-text {
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-primary);
  font-weight: 600;
  line-height: 1.6;
  margin-bottom: 12px;
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 36px;
  max-width: 760px;
  margin-left: auto;
  margin-right: auto;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

/* ==========================================================================
   模块化遥测仪表盘 (Compact Modular Telemetry Boxes)
   ========================================================================== */
.telemetry-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 20px;
  text-align: left;
}

.telemetry-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 22px 20px;
  position: relative;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.telemetry-box:hover {
  border-color: var(--status-emerald);
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.25);
}

.telemetry-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.6px;
  font-weight: 700;
}

.telemetry-val {
  font-size: 1.85rem;
  font-weight: 800;
  color: var(--text-primary);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  line-height: 1.15;
  margin-bottom: 6px;
}

.telemetry-meta {
  font-size: 0.8rem;
  color: var(--status-emerald);
  display: flex;
  align-items: center;
  gap: 6px;
  font-weight: 600;
}

/* ==========================================================================
   通用区块排版规范
   ========================================================================== */
.section-padding {
  padding: 80px 0;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 52px;
}

.section-tag {
  display: inline-block;
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--brand-primary);
  margin-bottom: 10px;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.8px;
  line-height: 1.25;
  margin-bottom: 14px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
}

/* ==========================================================================
   核心优势 (3个图文卡片)
   ========================================================================== */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 26px;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 34px 28px;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  position: relative;
}

.card:hover {
  transform: translateY(-4px);
  border-color: var(--brand-primary);
  box-shadow: var(--shadow-xl);
  background: var(--bg-card-hover);
}

.card-icon-wrap {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
  color: #ffffff;
}

.card-icon-red { background: linear-gradient(135deg, #f43f5e, #be123c); }
.card-icon-blue { background: linear-gradient(135deg, #0284c7, #2563eb); }
.card-icon-purple { background: linear-gradient(135deg, #8b5cf6, #6d28d9); }

.card-icon-wrap svg {
  width: 28px;
  height: 28px;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.card-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.68;
  flex-grow: 1;
}

.card-footer-metric {
  margin-top: 24px;
  padding-top: 18px;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.metric-value {
  font-size: 1.55rem;
  font-weight: 800;
  color: var(--brand-primary);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

.metric-label {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* ==========================================================================
   全球核心节点群与微互动 (Regional Node Clusters)
   ========================================================================== */
.node-clusters-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.node-cluster-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  cursor: default;
}

.node-cluster-card:hover {
  border-color: var(--status-emerald);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  background: var(--bg-card-hover);
}

.node-cluster-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.node-flag-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
}

.node-stats-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin-bottom: 14px;
  padding: 10px 12px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-sm);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

.node-stat-col span {
  display: block;
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
}

.node-stat-col strong {
  font-size: 0.95rem;
  color: var(--text-primary);
}

.node-cluster-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.node-tag {
  font-size: 0.74rem;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

/* ==========================================================================
   流媒体 & AI 支持图卡 (Strictly Exclude AI Spark Icons)
   ========================================================================== */
.showcase-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
  margin-top: 10px;
}

.showcase-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 38px;
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
  transition: var(--transition);
}

.showcase-card:hover {
  transform: translateY(-4px);
  border-color: var(--brand-primary);
  box-shadow: var(--shadow-xl);
}

.showcase-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  margin-bottom: 18px;
}

.badge-stream {
  background: rgba(225, 29, 72, 0.1);
  color: var(--brand-primary);
  border: 1px solid rgba(225, 29, 72, 0.2);
}

.badge-ai {
  background: rgba(99, 102, 241, 0.1);
  color: var(--brand-secondary);
  border: 1px solid rgba(99, 102, 241, 0.2);
}

.showcase-title {
  font-size: 1.65rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.showcase-desc {
  font-size: 0.98rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 26px;
}

.tag-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 26px;
}

.tag-item {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 5px;
  transition: var(--transition);
}

.tag-item:hover {
  background: var(--border-color);
  border-color: var(--brand-primary);
}

.tag-item strong {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
}

.tag-item span {
  font-size: 0.76rem;
  color: var(--status-emerald);
  font-weight: 600;
}

.feature-pill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.feature-pill {
  font-size: 0.82rem;
  padding: 5px 12px;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
}

.feature-pill svg {
  width: 14px;
  height: 14px;
  color: var(--status-emerald);
}

/* ==========================================================================
   协议与客户端工作台 (Protocol Switcher with 0ms Crossfade)
   ========================================================================== */
.protocol-workspace {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px;
  box-shadow: var(--shadow-sm);
  margin-top: 20px;
}

.protocol-tabs {
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 16px;
  margin-bottom: 28px;
  flex-wrap: wrap;
}

.protocol-tab-btn {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 0.92rem;
  padding: 9px 20px;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition);
  user-select: none;
}

.protocol-tab-btn:hover {
  color: var(--text-primary);
  border-color: var(--text-muted);
}

.protocol-tab-btn.active {
  background: var(--brand-gradient);
  color: #ffffff;
  border-color: transparent;
  box-shadow: 0 4px 12px var(--brand-glow);
}

.protocol-panels {
  position: relative;
  min-height: 220px;
}

/* 0ms 顺滑渐变切换 */
.protocol-panel {
  display: none;
  opacity: 0;
  transition: opacity 0.18s ease-in-out;
}

.protocol-panel.active {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 32px;
  align-items: center;
  opacity: 1;
}

.protocol-info h3 {
  font-size: 1.45rem;
  font-weight: 800;
  margin-bottom: 10px;
}

.protocol-info p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
  margin-bottom: 20px;
}

.protocol-qr-box {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.qr-placeholder {
  width: 140px;
  height: 140px;
  background: #ffffff;
  border-radius: var(--radius-sm);
  padding: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.qr-placeholder svg {
  width: 100%;
  height: 100%;
}

/* ==========================================================================
   套餐价格对比表 (参考网上真实套餐价格)
   ========================================================================== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 34px 24px;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
  position: relative;
  box-shadow: var(--shadow-sm);
}

.pricing-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
}

.pricing-card.featured {
  border: 2px solid var(--brand-primary);
  background: var(--bg-card);
  box-shadow: 0 10px 30px var(--brand-glow);
  transform: scale(1.02);
}

.pricing-card.featured:hover {
  transform: scale(1.02) translateY(-4px);
}

.featured-ribbon {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--brand-gradient);
  color: #ffffff;
  font-size: 0.78rem;
  font-weight: 800;
  padding: 4px 16px;
  border-radius: var(--radius-full);
  box-shadow: 0 4px 10px var(--brand-glow);
  white-space: nowrap;
}

.pricing-name {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 6px;
}

.pricing-desc {
  font-size: 0.86rem;
  color: var(--text-secondary);
  margin-bottom: 20px;
  min-height: 42px;
}

.pricing-price-wrap {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 22px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-color);
}

.currency {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--brand-primary);
}

.price-num {
  font-size: 2.75rem;
  font-weight: 900;
  line-height: 1;
  color: var(--text-primary);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

.price-cycle {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.pricing-features {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 28px;
  flex-grow: 1;
}

.pricing-feature-item {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.pricing-feature-item svg {
  width: 16px;
  height: 16px;
  color: var(--status-emerald);
  flex-shrink: 0;
}

.pricing-feature-item strong {
  color: var(--text-primary);
}

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

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.review-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-color);
  box-shadow: var(--shadow-md);
}

.review-stars {
  display: flex;
  gap: 4px;
  color: #f59e0b;
  margin-bottom: 14px;
}

.review-stars svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

.review-text {
  font-size: 0.95rem;
  line-height: 1.68;
  color: var(--text-secondary);
  margin-bottom: 20px;
  flex-grow: 1;
}

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

.user-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--brand-primary);
  border: 1px solid var(--border-color);
}

.user-meta h4 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
}

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

/* ==========================================================================
   常见问题解答 (FAQ)
   ========================================================================== */
.faq-wrap {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

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

.faq-item[open] {
  border-color: var(--brand-primary);
  box-shadow: var(--shadow-md);
}

.faq-question {
  padding: 20px 24px;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
}

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

.faq-toggle-icon {
  width: 20px;
  height: 20px;
  color: var(--text-muted);
  transition: transform 0.3s ease;
  flex-shrink: 0;
}

.faq-item[open] .faq-toggle-icon {
  transform: rotate(180deg);
  color: var(--brand-primary);
}

.faq-answer {
  padding: 0 24px 22px;
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
  border-top: 1px dashed var(--border-color);
  padding-top: 16px;
}

/* ==========================================================================
   底部 CTA 横幅 (Pre-footer CTA Banner)
   ========================================================================== */
.cta-banner {
  background: var(--brand-gradient);
  border-radius: var(--radius-lg);
  padding: 56px 40px;
  text-align: center;
  color: #ffffff;
  position: relative;
  overflow: hidden;
  box-shadow: 0 15px 35px var(--brand-glow);
  margin-top: 40px;
}

.cta-banner-glow {
  position: absolute;
  top: -50px;
  right: -50px;
  width: 250px;
  height: 250px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.15);
  filter: blur(40px);
  pointer-events: none;
}

.cta-banner h2 {
  font-size: 2.2rem;
  font-weight: 900;
  margin-bottom: 14px;
  letter-spacing: -0.5px;
}

.cta-banner p {
  font-size: 1.1rem;
  opacity: 0.92;
  margin-bottom: 28px;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

.btn-white {
  background: #ffffff;
  color: var(--brand-primary) !important;
  font-weight: 700;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.15);
}

.btn-white:hover {
  background: #f8fafc;
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

/* ==========================================================================
   页脚 Footer (严格遵循规范：仅保留4个标题链接且打开新页面)
   ========================================================================== */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 44px 0;
  margin-top: 80px;
  transition: var(--transition);
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 36px;
  list-style: none;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.footer-link {
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--text-secondary);
  position: relative;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.footer-link:hover {
  color: var(--brand-primary);
  background: var(--bg-tertiary);
}

.footer-copyright {
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ==========================================================================
   子页面通用排版
   ========================================================================== */
.subpage-hero {
  padding: 60px 0 40px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  text-align: center;
}

.subpage-title {
  font-size: 2.4rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.subpage-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto;
}

.subpage-content {
  padding: 60px 0 80px;
  max-width: 880px;
  margin: 0 auto;
}

.content-block {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 40px;
  margin-bottom: 30px;
  box-shadow: var(--shadow-sm);
}

.content-block h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
}

.content-block h2::before {
  content: "";
  display: inline-block;
  width: 4px;
  height: 20px;
  background: var(--brand-primary);
  border-radius: 2px;
}

.content-block p {
  color: var(--text-secondary);
  font-size: 0.98rem;
  line-height: 1.8;
  margin-bottom: 16px;
}

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

.content-block ul {
  padding-left: 20px;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 16px;
}

.content-block li {
  margin-bottom: 8px;
}

.node-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 20px;
}

.node-box {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 16px;
}

.node-box h4 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.node-badge {
  font-size: 0.72rem;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  background: rgba(16, 185, 129, 0.15);
  color: var(--status-emerald);
  font-weight: 700;
}

.node-box p {
  font-size: 0.85rem;
  margin: 0;
  color: var(--text-muted);
}

/* ==========================================================================
   长篇深度 SEO 文章排版规范 (Article Layout & Typography)
   ========================================================================== */
.article-header {
  margin-bottom: 36px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
}

.article-breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

.article-breadcrumb a:hover {
  color: var(--brand-primary);
}

.article-title {
  font-size: 2.3rem;
  font-weight: 900;
  line-height: 1.3;
  margin-bottom: 18px;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 0.88rem;
  color: var(--text-muted);
}

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

/* 目录卡片 (Table of Contents) */
.article-toc {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--brand-primary);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  margin: 32px 0 40px;
}

.toc-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

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

.toc-list a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  transition: var(--transition);
}

.toc-list a:hover {
  color: var(--brand-primary);
  padding-left: 4px;
}

/* 文章正文样式 */
.article-body h2 {
  font-size: 1.65rem;
  font-weight: 800;
  margin: 44px 0 18px;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
  scroll-margin-top: calc(var(--nav-height) + 24px);
}

.article-body h2::before {
  content: "";
  display: inline-block;
  width: 5px;
  height: 22px;
  background: var(--brand-primary);
  border-radius: 2px;
}

.article-body h3 {
  font-size: 1.28rem;
  font-weight: 700;
  margin: 30px 0 14px;
  color: var(--text-primary);
  scroll-margin-top: calc(var(--nav-height) + 24px);
}

.article-body p {
  font-size: 1.02rem;
  line-height: 1.85;
  color: var(--text-secondary);
  margin-bottom: 20px;
}

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

.article-body ul, .article-body ol {
  padding-left: 24px;
  margin-bottom: 22px;
  color: var(--text-secondary);
  line-height: 1.85;
  font-size: 1rem;
}

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

.article-callout {
  background: rgba(99, 102, 241, 0.08);
  border: 1px solid rgba(99, 102, 241, 0.25);
  border-left: 4px solid var(--brand-secondary);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin: 28px 0;
}

.article-callout p {
  margin-bottom: 0;
  color: var(--text-primary);
  font-size: 0.96rem;
}

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

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

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

.article-table td {
  padding: 13px 18px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-secondary);
}

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

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

/* 代码与命令行 */
.article-code-block {
  background: #0d1117;
  color: #e6edf3;
  border-radius: var(--radius-md);
  padding: 18px 22px;
  margin: 24px 0;
  overflow-x: auto;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.88rem;
  line-height: 1.6;
  border: 1px solid #30363d;
}

/* 文章专属 CTA 推荐框 */
.article-cta-box {
  background: var(--brand-gradient);
  color: #ffffff;
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  margin: 44px 0;
  text-align: center;
  box-shadow: 0 10px 25px var(--brand-glow);
}

.article-cta-box h3 {
  font-size: 1.55rem;
  font-weight: 800;
  margin-bottom: 10px;
  color: #ffffff;
}

.article-cta-box p {
  color: rgba(255, 255, 255, 0.92);
  max-width: 600px;
  margin: 0 auto 22px;
  font-size: 1rem;
}

/* 文章底部的相关阅读 (Related Reading) */
.article-related-section {
  margin-top: 50px;
  padding-top: 36px;
  border-top: 1px solid var(--border-color);
}

.article-related-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 20px;
}

.related-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.related-card:hover {
  transform: translateY(-3px);
  border-color: var(--brand-primary);
  box-shadow: var(--shadow-md);
}

.related-card h4 {
  font-size: 0.98rem;
  font-weight: 700;
  margin-bottom: 8px;
  line-height: 1.45;
  color: var(--text-primary);
}

.related-card p {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.55;
  flex-grow: 1;
}

/* ==========================================================================
   响应式媒体查询 (Mobile Single-Column Adaptations)
   ========================================================================== */
@media (max-width: 1080px) {
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .telemetry-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .node-clusters-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 992px) {
  .grid-3,
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .protocol-panel.active {
    grid-template-columns: 1fr;
  }

  .pricing-card.featured {
    transform: none;
  }

  .pricing-card.featured:hover {
    transform: translateY(-4px);
  }
}

@media (max-width: 768px) {
  :root {
    --nav-height: 64px;
  }

  .site-header {
    padding: 0 4px;
  }

  .brand-logo-img {
    height: 36px;
  }

  /* 移动端横向滑动或自适应导航 */
  .nav-links {
    display: none;
  }

  .hero-title {
    font-size: 2.2rem;
    letter-spacing: -0.5px;
  }

  .hero-subtitle {
    font-size: 1.05rem;
  }

  .hero-desc {
    font-size: 0.95rem;
  }

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

  .hero-actions .btn {
    width: 100%;
    min-height: 50px;
    font-size: 1.05rem;
  }

  .grid-3,
  .pricing-grid,
  .reviews-grid,
  .showcase-grid,
  .telemetry-grid,
  .node-clusters-grid,
  .node-grid {
    grid-template-columns: 1fr;
  }

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

  .section-padding {
    padding: 56px 0;
  }

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

  .cta-banner {
    padding: 40px 24px;
  }

  .cta-banner h2 {
    font-size: 1.75rem;
  }

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

  .footer-link {
    font-size: 1.05rem;
    padding: 8px 16px;
  }

  .content-block {
    padding: 24px 20px;
  }
}