:root {
  /* 纯白科技明亮模式 (默认) */
  --nc-bg: #f8fafc;
  --nc-bg-alt: #ffffff;
  --nc-card-bg: #ffffff;
  --nc-card-border: #e2e8f0;
  --nc-card-hover: #ffffff;
  --nc-card-shadow: 0 4px 16px rgba(0, 0, 0, 0.04);
  --nc-card-hover-shadow: 0 20px 40px rgba(0, 102, 255, 0.12);
  --nc-primary: #0066ff;
  --nc-primary-glow: rgba(0, 102, 255, 0.25);
  --nc-cyan: #0284c7;
  --nc-purple: #7c3aed;
  --nc-text-main: #0f172a;
  --nc-text-muted: #475569;
  --nc-text-dim: #64748b;
  --nc-header-bg: rgba(255, 255, 255, 0.85);
  --nc-header-scrolled: rgba(255, 255, 255, 0.98);
  --nc-footer-bg: #ffffff;
  --nc-footer-border: #e2e8f0;
  --nc-sub-card-bg: #f8fafc;
  --nc-sub-card-border: #edf2f7;
  --nc-font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

/* 兼容暗黑科技模式 (可通过类名切换) */
body.nc-theme-dark {
  --nc-bg: #0b0f19;
  --nc-bg-alt: #111827;
  --nc-card-bg: rgba(22, 30, 49, 0.75);
  --nc-card-border: rgba(255, 255, 255, 0.08);
  --nc-card-hover: rgba(30, 42, 69, 0.9);
  --nc-card-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
  --nc-card-hover-shadow: 0 16px 36px rgba(0, 102, 255, 0.18);
  --nc-primary: #0066ff;
  --nc-primary-glow: rgba(0, 102, 255, 0.35);
  --nc-cyan: #00e5ff;
  --nc-purple: #8b5cf6;
  --nc-text-main: #f3f4f6;
  --nc-text-muted: #9ca3af;
  --nc-text-dim: #6b7280;
  --nc-header-bg: rgba(11, 15, 25, 0.8);
  --nc-header-scrolled: rgba(11, 15, 25, 0.95);
  --nc-footer-bg: #070a11;
  --nc-footer-border: rgba(255, 255, 255, 0.08);
  --nc-sub-card-bg: rgba(11, 15, 25, 0.6);
  --nc-sub-card-border: rgba(255, 255, 255, 0.08);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--nc-font);
  background-color: var(--nc-bg);
  color: var(--nc-text-main);
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* 顶部流光背景粒子网格 */
.nc-bg-grid {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-image: 
    linear-gradient(to right, rgba(0, 102, 255, 0.035) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(0, 102, 255, 0.035) 1px, transparent 1px);
  background-size: 36px 36px;
  pointer-events: none;
  z-index: 0;
}

body.nc-theme-dark .nc-bg-grid {
  background-image: 
    linear-gradient(to right, rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
}

.nc-glow-sphere-1 {
  position: absolute;
  top: -120px;
  left: 20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(0, 102, 255, 0.08) 0%, transparent 70%);
  filter: blur(80px);
  pointer-events: none;
  z-index: 0;
}

body.nc-theme-dark .nc-glow-sphere-1 {
  background: radial-gradient(circle, rgba(0, 102, 255, 0.18) 0%, transparent 70%);
}

.nc-glow-sphere-2 {
  position: absolute;
  top: 400px;
  right: -80px;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.06) 0%, transparent 70%);
  filter: blur(80px);
  pointer-events: none;
  z-index: 0;
}

body.nc-theme-dark .nc-glow-sphere-2 {
  background: radial-gradient(circle, rgba(139, 92, 246, 0.15) 0%, transparent 70%);
}

.nc-wrapper {
  position: relative;
  z-index: 1;
}

.nc-container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

/* 头部导航 */
.nc-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 72px;
  background: var(--nc-header-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--nc-card-border);
  z-index: 1000;
  transition: all 0.3s ease;
}

.nc-header.scrolled {
  background: var(--nc-header-scrolled);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
  border-bottom-color: rgba(0, 102, 255, 0.15);
}

body.nc-theme-dark .nc-header.scrolled {
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
  border-bottom-color: rgba(0, 102, 255, 0.2);
}

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

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

.nc-logo-icon {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: linear-gradient(135deg, #0066ff 0%, #0052cc 60%, #7c3aed 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 800;
  font-size: 20px;
  box-shadow: 0 4px 14px rgba(0, 102, 255, 0.35);
}

.nc-logo-text {
  font-size: 20px;
  font-weight: 700;
  color: var(--nc-text-main);
  letter-spacing: 0.5px;
}

.nc-logo-badge {
  font-size: 11px;
  padding: 2px 7px;
  border-radius: 20px;
  background: rgba(0, 102, 255, 0.08);
  color: var(--nc-primary);
  border: 1px solid rgba(0, 102, 255, 0.2);
  font-weight: 600;
}

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

.nc-nav-link {
  color: var(--nc-text-muted);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  transition: color 0.2s, text-shadow 0.2s;
}

.nc-nav-link:hover, .nc-nav-link.active {
  color: var(--nc-primary);
  font-weight: 600;
}

body.nc-theme-dark .nc-nav-link:hover, 
body.nc-theme-dark .nc-nav-link.active {
  color: #fff;
  text-shadow: 0 0 12px rgba(255, 255, 255, 0.6);
}

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

.nc-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 9px 20px;
  font-size: 14px;
  font-weight: 600;
  border-radius: 8px;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.25s ease;
  border: none;
}

.nc-btn-sm {
  padding: 7px 15px;
  font-size: 13px;
}

.nc-btn-ghost {
  background: #ffffff;
  color: var(--nc-text-muted);
  border: 1px solid var(--nc-card-border);
}

.nc-btn-ghost:hover {
  color: var(--nc-primary);
  border-color: rgba(0, 102, 255, 0.3);
  background: #f1f5f9;
}

body.nc-theme-dark .nc-btn-ghost {
  background: transparent;
  color: var(--nc-text-muted);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

body.nc-theme-dark .nc-btn-ghost:hover {
  color: #fff;
  border-color: rgba(255, 255, 255, 0.4);
  background: rgba(255, 255, 255, 0.05);
}

.nc-btn-primary {
  background: linear-gradient(135deg, #0066ff 0%, #0052cc 100%);
  color: #fff;
  box-shadow: 0 4px 14px var(--nc-primary-glow);
}

.nc-btn-primary:hover {
  background: linear-gradient(135deg, #1a75ff 0%, #0066ff 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 102, 255, 0.4);
  color: #fff;
}

.nc-btn-cyan {
  background: linear-gradient(135deg, #0284c7 0%, #0066ff 100%);
  color: #fff;
  font-weight: 700;
  box-shadow: 0 4px 14px rgba(2, 132, 199, 0.25);
}

.nc-btn-cyan:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(2, 132, 199, 0.4);
  color: #fff;
}

body.nc-theme-dark .nc-btn-cyan {
  background: linear-gradient(135deg, #00e5ff 0%, #0066ff 100%);
  color: #0b0f19;
}

/* 顶部公告条 */
.nc-broadcast-bar {
  margin-top: 72px;
  background: #eff6ff;
  border-bottom: 1px solid #dbeafe;
  padding: 10px 0;
  font-size: 13px;
  color: #1d4ed8;
}

body.nc-theme-dark .nc-broadcast-bar {
  background: rgba(0, 102, 255, 0.08);
  border-bottom: 1px solid rgba(0, 102, 255, 0.15);
  color: var(--nc-cyan);
}

.nc-broadcast-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.nc-broadcast-icon {
  animation: pulse 2s infinite;
}

/* Hero 区域 */
.nc-hero {
  padding: 80px 0 60px;
  text-align: center;
  position: relative;
}

.nc-hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  border-radius: 30px;
  background: #e0f2fe;
  border: 1px solid #bae6fd;
  font-size: 13px;
  color: #0284c7;
  font-weight: 600;
  margin-bottom: 24px;
}

body.nc-theme-dark .nc-hero-pill {
  background: rgba(0, 229, 255, 0.08);
  border-color: rgba(0, 229, 255, 0.3);
  color: var(--nc-cyan);
}

.nc-hero-title {
  font-size: 52px;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #0f172a 20%, #1e3a8a 60%, #0066ff 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.5px;
}

body.nc-theme-dark .nc-hero-title {
  background: linear-gradient(135deg, #ffffff 30%, #a5b4fc 70%, #00e5ff 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nc-hero-sub {
  font-size: 18px;
  color: var(--nc-text-muted);
  max-width: 780px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

.nc-hero-cta {
  display: flex;
  justify-content: center;
  gap: 18px;
  margin-bottom: 50px;
}

.nc-hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  max-width: 960px;
  margin: 0 auto;
  padding: 24px;
  background: var(--nc-card-bg);
  border: 1px solid var(--nc-card-border);
  border-radius: 16px;
  backdrop-filter: blur(12px);
  box-shadow: var(--nc-card-shadow);
}

.nc-stat-item {
  text-align: center;
}

.nc-stat-num {
  font-size: 32px;
  font-weight: 800;
  background: linear-gradient(135deg, #0066ff 0%, #0284c7 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 4px;
}

body.nc-theme-dark .nc-stat-num {
  background: linear-gradient(135deg, #00e5ff 0%, #0066ff 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nc-stat-label {
  font-size: 13px;
  color: var(--nc-text-dim);
}

/* 核心板块标题 */
.nc-section {
  padding: 90px 0;
  position: relative;
}

.nc-section-header {
  text-align: center;
  margin-bottom: 54px;
}

.nc-section-tag {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--nc-primary);
  letter-spacing: 2px;
  margin-bottom: 10px;
  display: inline-block;
}

body.nc-theme-dark .nc-section-tag {
  color: var(--nc-cyan);
}

.nc-section-title {
  font-size: 36px;
  font-weight: 800;
  color: var(--nc-text-main);
  margin-bottom: 14px;
  letter-spacing: -0.5px;
}

.nc-section-desc {
  font-size: 16px;
  color: var(--nc-text-muted);
  max-width: 600px;
  margin: 0 auto;
}

/* 产品卡片矩阵 */
.nc-product-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.nc-product-card {
  background: var(--nc-card-bg);
  border: 1px solid var(--nc-card-border);
  border-radius: 16px;
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: var(--nc-card-shadow);
}

.nc-product-card:hover {
  transform: translateY(-8px);
  border-color: rgba(0, 102, 255, 0.35);
  background: var(--nc-card-hover);
  box-shadow: var(--nc-card-hover-shadow);
}

.nc-card-badge {
  position: absolute;
  top: 18px;
  right: 18px;
  font-size: 11px;
  font-weight: 700;
  padding: 3px 9px;
  border-radius: 20px;
  background: linear-gradient(135deg, #e0f2fe 0%, #dbeafe 100%);
  color: #0369a1;
  border: 1px solid #bae6fd;
}

body.nc-theme-dark .nc-card-badge {
  background: linear-gradient(135deg, #00e5ff 0%, #0066ff 100%);
  color: #0b0f19;
  border: none;
}

.nc-card-tag {
  font-size: 12px;
  color: var(--nc-cyan);
  font-weight: 600;
  margin-bottom: 6px;
}

.nc-card-title {
  font-size: 19px;
  font-weight: 700;
  color: var(--nc-text-main);
  margin-bottom: 16px;
  line-height: 1.4;
}

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

.nc-price-sym {
  font-size: 18px;
  color: var(--nc-primary);
  font-weight: 700;
}

.nc-price-val {
  font-size: 38px;
  font-weight: 800;
  color: var(--nc-text-main);
  font-family: var(--nc-font);
}

.nc-price-cycle {
  font-size: 13px;
  color: var(--nc-text-dim);
}

.nc-card-specs {
  list-style: none;
  margin-bottom: 28px;
  flex-grow: 1;
}

.nc-spec-item {
  font-size: 13px;
  color: var(--nc-text-muted);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.nc-spec-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--nc-primary);
  box-shadow: 0 0 6px rgba(0, 102, 255, 0.4);
}

.nc-card-btn {
  width: 100%;
  padding: 12px;
  text-align: center;
  font-weight: 600;
}

/* 测速仪表盘 */
.nc-speed-panel {
  background: var(--nc-card-bg);
  border: 1px solid var(--nc-card-border);
  border-radius: 18px;
  padding: 32px;
  box-shadow: var(--nc-card-shadow);
}

.nc-speed-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.nc-node-card {
  background: var(--nc-sub-card-bg);
  border: 1px solid var(--nc-sub-card-border);
  border-radius: 12px;
  padding: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: all 0.25s;
}

.nc-node-card:hover {
  border-color: rgba(0, 102, 255, 0.35);
  background: #ffffff;
  box-shadow: 0 6px 18px rgba(0, 102, 255, 0.08);
  transform: translateX(4px);
}

body.nc-theme-dark .nc-node-card:hover {
  background: var(--nc-sub-card-bg);
  border-color: rgba(0, 102, 255, 0.4);
  box-shadow: none;
}

.nc-node-info h4 {
  font-size: 16px;
  color: var(--nc-text-main);
  margin-bottom: 4px;
}

.nc-node-type {
  font-size: 12px;
  color: var(--nc-cyan);
  margin-bottom: 8px;
  font-weight: 600;
}

.nc-node-route {
  font-size: 12px;
  color: var(--nc-text-dim);
}

.nc-node-ping-box {
  text-align: right;
}

.nc-node-ping {
  font-size: 20px;
  font-weight: 700;
  color: #059669;
}

body.nc-theme-dark .nc-node-ping {
  color: #10b981;
}

.nc-node-ip {
  font-size: 11px;
  color: var(--nc-text-dim);
  margin-top: 4px;
}

/* 核心特性与优势 */
.nc-features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.nc-feature-card {
  background: var(--nc-card-bg);
  border: 1px solid var(--nc-card-border);
  border-radius: 16px;
  padding: 32px 24px;
  text-align: left;
  transition: all 0.3s;
  box-shadow: var(--nc-card-shadow);
}

.nc-feature-card:hover {
  border-color: rgba(0, 102, 255, 0.35);
  transform: translateY(-6px);
  box-shadow: var(--nc-card-hover-shadow);
}

.nc-feature-icon {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  background: #eff6ff;
  border: 1px solid #dbeafe;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--nc-primary);
  font-size: 24px;
  margin-bottom: 20px;
}

body.nc-theme-dark .nc-feature-icon {
  background: rgba(0, 102, 255, 0.15);
  border-color: rgba(0, 102, 255, 0.3);
  color: var(--nc-cyan);
}

.nc-feature-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--nc-text-main);
  margin-bottom: 12px;
}

.nc-feature-desc {
  font-size: 14px;
  color: var(--nc-text-muted);
  line-height: 1.6;
}

/* 常见问题 FAQ */
.nc-faq-list {
  max-width: 860px;
  margin: 0 auto;
}

.nc-faq-item {
  background: var(--nc-card-bg);
  border: 1px solid var(--nc-card-border);
  border-radius: 12px;
  margin-bottom: 16px;
  overflow: hidden;
  transition: all 0.2s;
  box-shadow: var(--nc-card-shadow);
}

.nc-faq-item.active {
  border-color: rgba(0, 102, 255, 0.4);
}

.nc-faq-question {
  padding: 20px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  font-size: 16px;
  font-weight: 600;
  color: var(--nc-text-main);
}

.nc-faq-toggle {
  font-size: 20px;
  color: var(--nc-primary);
  transition: transform 0.25s;
}

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

.nc-faq-answer {
  padding: 0 24px 20px;
  font-size: 14px;
  color: var(--nc-text-muted);
  line-height: 1.7;
  display: none;
}

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

/* 页脚 */
.nc-footer {
  background: var(--nc-footer-bg);
  border-top: 1px solid var(--nc-footer-border);
  padding: 70px 0 30px;
  position: relative;
  z-index: 10;
}

.nc-footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 40px;
  margin-bottom: 50px;
}

.nc-footer-brand p {
  color: var(--nc-text-muted);
  font-size: 14px;
  margin-top: 16px;
  line-height: 1.7;
}

.nc-footer-col h5 {
  font-size: 16px;
  color: var(--nc-text-main);
  margin-bottom: 20px;
  font-weight: 700;
}

.nc-footer-links {
  list-style: none;
}

.nc-footer-links li {
  margin-bottom: 12px;
}

.nc-footer-links a {
  color: var(--nc-text-dim);
  text-decoration: none;
  font-size: 14px;
  transition: color 0.2s;
}

.nc-footer-links a:hover {
  color: var(--nc-primary);
}

.nc-footer-contact p {
  font-size: 14px;
  color: var(--nc-text-muted);
  margin-bottom: 10px;
}

.nc-footer-bottom {
  text-align: center;
  padding-top: 30px;
  border-top: 1px solid var(--nc-footer-border);
  font-size: 13px;
  color: var(--nc-text-dim);
}

/* 浮动客服挂件 */
.nc-float-widget {
  position: fixed;
  right: 24px;
  bottom: 30px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  z-index: 999;
}

.nc-float-btn {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: #ffffff;
  border: 1px solid var(--nc-card-border);
  color: var(--nc-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
  transition: all 0.25s;
  text-decoration: none;
}

body.nc-theme-dark .nc-float-btn {
  background: rgba(17, 24, 39, 0.9);
  border-color: rgba(0, 229, 255, 0.3);
  color: var(--nc-cyan);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.5);
}

.nc-float-btn:hover {
  background: var(--nc-primary);
  color: #fff;
  transform: translateY(-3px);
  box-shadow: 0 6px 20px var(--nc-primary-glow);
}

/* 响应式适配 */
@media (max-width: 1024px) {
  .nc-product-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .nc-features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .nc-footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nc-nav-links {
    display: none;
  }
  .nc-hero-title {
    font-size: 34px;
  }
  .nc-hero-sub {
    font-size: 15px;
  }
  .nc-hero-stats {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    padding: 16px;
  }
  .nc-stat-num {
    font-size: 26px;
  }
  .nc-product-grid {
    grid-template-columns: 1fr;
  }
  .nc-speed-grid {
    grid-template-columns: 1fr;
  }
  .nc-features-grid {
    grid-template-columns: 1fr;
  }
  .nc-footer-grid {
    grid-template-columns: 1fr;
  }
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
    transform: scale(1);
  }
  50% {
    opacity: 0.6;
    transform: scale(1.1);
  }
}