/* ==========================================================================
   灵动云 (Lingdongyun.cfd) - 官方落地页全套设计系统
   ========================================================================== */

/* 核心变量定义 */
:root {
  --bg-primary: #070c18;
  --bg-secondary: #0f172a;
  --bg-card: rgba(15, 23, 42, 0.75);
  --bg-card-hover: rgba(30, 41, 59, 0.85);
  --border-color: rgba(56, 189, 248, 0.18);
  --border-glow: rgba(56, 189, 248, 0.5);
  
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-highlight: #38bdf8;
  
  /* 蓝白渐变配色方案 (指令3) */
  --gradient-blue-white: linear-gradient(135deg, #38bdf8 0%, #818cf8 40%, #e0f2fe 80%, #ffffff 100%);
  --gradient-sky-aura: linear-gradient(180deg, rgba(14, 165, 233, 0.15) 0%, rgba(3, 105, 161, 0.05) 50%, transparent 100%);
  --gradient-button: linear-gradient(135deg, #0284c7 0%, #2563eb 50%, #4f46e5 100%);
  --gradient-button-hover: linear-gradient(135deg, #0369a1 0%, #1d4ed8 50%, #4338ca 100%);
  
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  
  --shadow-glow: 0 0 25px rgba(56, 189, 248, 0.25);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 基础重置 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-primary);
  color: var(--text-main);
  overflow-x: hidden;
}

body {
  position: relative;
  min-height: 100vh;
  line-height: 1.6;
}

/* ==========================================================================
   指令 2：天空与云端动态背景 (Sky Backdrop & Animated Cloud Elements)
   ========================================================================== */
.sky-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -2;
  background: 
    radial-gradient(circle at 50% 0%, rgba(56, 189, 248, 0.18) 0%, transparent 50%),
    radial-gradient(circle at 85% 30%, rgba(99, 102, 241, 0.12) 0%, transparent 40%),
    radial-gradient(circle at 15% 70%, rgba(14, 165, 233, 0.15) 0%, transparent 45%),
    linear-gradient(180deg, #030712 0%, #0b1528 40%, #070c18 100%);
}

.cloud-layer {
  position: fixed;
  top: 0;
  left: 0;
  width: 200%;
  height: 100%;
  z-index: -1;
  pointer-events: none;
  opacity: 0.35;
  background: 
    radial-gradient(ellipse at 20% 20%, rgba(186, 230, 253, 0.15) 0%, transparent 40%),
    radial-gradient(ellipse at 70% 60%, rgba(147, 197, 253, 0.12) 0%, transparent 50%);
  animation: floatClouds 60s linear infinite;
}

@keyframes floatClouds {
  0% { transform: translateX(0); }
  50% { transform: translateX(-25%); }
  100% { transform: translateX(0); }
}

/* 全局蓝白渐变字体 (指令 3) */
.text-gradient {
  background: var(--gradient-blue-white);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline-block;
}

.text-highlight {
  color: var(--text-highlight);
}

/* Container */
.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ==========================================================================
   导航栏 Header Navbar
   ========================================================================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(7, 12, 24, 0.75);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
}

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

.logo img {
  width: 42px;
  height: 42px;
  filter: drop-shadow(0 0 8px rgba(56, 189, 248, 0.6));
}

.logo-text {
  font-size: 1.4rem;
  font-weight: 800;
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--text-main);
  text-shadow: 0 0 10px rgba(56, 189, 248, 0.5);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 0.75rem 1.75rem;
  background: var(--gradient-button);
  color: #ffffff;
  font-weight: 700;
  font-size: 0.95rem;
  border-radius: 9999px;
  text-decoration: none;
  box-shadow: var(--shadow-glow);
  transition: var(--transition);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn-primary:hover {
  background: var(--gradient-button-hover);
  transform: translateY(-2px);
  box-shadow: 0 0 35px rgba(56, 189, 248, 0.45);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 0.75rem 1.75rem;
  background: rgba(30, 41, 59, 0.8);
  color: var(--text-main);
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: 9999px;
  text-decoration: none;
  border: 1px solid var(--border-color);
  transition: var(--transition);
}

.btn-secondary:hover {
  background: rgba(51, 65, 85, 0.9);
  border-color: var(--text-highlight);
  transform: translateY(-2px);
}

/* ==========================================================================
   Hero Banner
   ========================================================================== */
.hero {
  padding: 160px 0 100px;
  text-align: center;
  position: relative;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.3);
  border-radius: 9999px;
  color: var(--text-highlight);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}

.hero h1 {
  font-size: 3.5rem;
  line-height: 1.15;
  font-weight: 900;
  letter-spacing: -1px;
  margin-bottom: 1.5rem;
}

.hero p {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 780px;
  margin: 0 auto 2.5rem;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  margin-bottom: 3.5rem;
  flex-wrap: wrap;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1.5rem;
  max-width: 900px;
  margin: 0 auto;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 1.5rem;
  border-radius: var(--radius-md);
  backdrop-filter: blur(12px);
}

.stat-card .num {
  font-size: 2.2rem;
  font-weight: 800;
  background: var(--gradient-blue-white);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.stat-card .label {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-top: 4px;
}

/* ==========================================================================
   指令 5：实时节点速度表 (Real-time Node Speed Monitor)
   ========================================================================== */
.section {
  padding: 90px 0;
}

.section-title {
  text-align: center;
  margin-bottom: 3.5rem;
}

.section-title h2 {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 1rem;
}

.section-title p {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 640px;
  margin: 0 auto;
}

.speed-monitor-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  backdrop-filter: blur(16px);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.speed-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.live-indicator {
  display: flex;
  align-items: center;
  gap: 8px;
  color: #4ade80;
  font-weight: 600;
  font-size: 0.9rem;
}

.dot-pulse {
  width: 10px;
  height: 10px;
  background-color: #4ade80;
  border-radius: 50%;
  box-shadow: 0 0 10px #4ade80;
  animation: pulse 1.5s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.2); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

.speed-table-wrapper {
  overflow-x: auto;
}

.speed-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
}

.speed-table th {
  padding: 1rem;
  background: rgba(30, 41, 59, 0.6);
  color: var(--text-highlight);
  font-size: 0.875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  border-bottom: 1px solid var(--border-color);
}

.speed-table td {
  padding: 1.1rem 1rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  font-size: 0.95rem;
}

.speed-table tr:hover {
  background: rgba(56, 189, 248, 0.05);
}

.flag-icon {
  font-size: 1.2rem;
  margin-right: 8px;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 9999px;
  font-size: 0.8rem;
  font-weight: 600;
}

.status-badge.fast {
  background: rgba(74, 222, 128, 0.15);
  color: #4ade80;
  border: 1px solid rgba(74, 222, 128, 0.3);
}

.status-badge.ultra {
  background: rgba(56, 189, 248, 0.15);
  color: #38bdf8;
  border: 1px solid rgba(56, 189, 248, 0.3);
}

.ping-bar-container {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 140px;
}

.ping-bar-bg {
  flex: 1;
  height: 6px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
  overflow: hidden;
}

.ping-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, #38bdf8, #4ade80);
  border-radius: 3px;
  transition: width 0.5s ease;
}

.ping-ms {
  font-family: monospace;
  font-weight: 600;
  font-size: 0.9rem;
  min-width: 45px;
}

/* ==========================================================================
   价格套餐 Pricing Cards
   ========================================================================== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.price-card {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2.5rem 2rem;
  backdrop-filter: blur(16px);
  display: flex;
  flex-direction: column;
  transition: var(--transition);
}

.price-card:hover {
  transform: translateY(-8px);
  border-color: var(--text-highlight);
  box-shadow: 0 15px 35px rgba(56, 189, 248, 0.2);
}

.price-card.popular {
  border: 2px solid #38bdf8;
  background: linear-gradient(180deg, rgba(14, 165, 233, 0.12) 0%, rgba(15, 23, 42, 0.85) 100%);
}

.popular-badge {
  position: absolute;
  top: -14px;
  right: 24px;
  background: var(--gradient-button);
  color: white;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 4px 14px;
  border-radius: 9999px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  box-shadow: 0 4px 12px rgba(56, 189, 248, 0.4);
}

.price-header h3 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.price-header p {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-bottom: 1.5rem;
}

.price-amount {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 2rem;
}

.currency {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-highlight);
}

.amount {
  font-size: 3rem;
  font-weight: 900;
  background: var(--gradient-blue-white);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.period {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.price-features {
  list-style: none;
  margin-bottom: 2rem;
  flex: 1;
}

.price-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 0.9rem;
  font-size: 0.95rem;
  color: #cbd5e1;
}

.price-features li svg {
  color: #38bdf8;
  flex-shrink: 0;
}

/* ==========================================================================
   指令 4：客户评论 平排上下自动展示 (Customer Reviews Auto Marquee Slider)
   ========================================================================== */
.reviews-wrapper {
  overflow: hidden;
  position: relative;
  width: 100%;
  padding: 1rem 0;
}

.reviews-track {
  display: flex;
  gap: 1.5rem;
  width: max-content;
  animation: marqueeHorizontal 45s linear infinite;
}

.reviews-track:hover {
  animation-play-state: paused;
}

@keyframes marqueeHorizontal {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

.review-card {
  width: 350px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  backdrop-filter: blur(12px);
  flex-shrink: 0;
}

.review-user {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 1rem;
}

.avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--gradient-button);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  color: white;
  font-size: 1.1rem;
  box-shadow: 0 0 10px rgba(56, 189, 248, 0.4);
}

.user-info h4 {
  font-size: 1rem;
  font-weight: 700;
}

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

.stars {
  color: #fbbf24;
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
}

.review-card p {
  color: #cbd5e1;
  font-size: 0.9rem;
  line-height: 1.6;
}

/* ==========================================================================
   文章推荐与 SEO 专栏 (Article Grid & SEO Matrix)
   ========================================================================== */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  backdrop-filter: blur(12px);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.article-card:hover {
  transform: translateY(-5px);
  border-color: var(--text-highlight);
  box-shadow: 0 12px 30px rgba(56, 189, 248, 0.15);
}

.article-tag {
  display: inline-block;
  padding: 4px 10px;
  background: rgba(56, 189, 248, 0.12);
  color: var(--text-highlight);
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: 4px;
  margin-bottom: 1rem;
  width: max-content;
}

.article-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

.article-card h3 a {
  color: var(--text-main);
  text-decoration: none;
  transition: var(--transition);
}

.article-card h3 a:hover {
  color: var(--text-highlight);
}

.article-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 1.25rem;
  flex: 1;
  line-height: 1.6;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: #64748b;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 1rem;
}

/* ==========================================================================
   FAQ 常见问题折叠面板
   ========================================================================== */
.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  backdrop-filter: blur(12px);
  transition: var(--transition);
}

.faq-question {
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-weight: 700;
  font-size: 1.05rem;
}

.faq-question svg {
  transition: transform 0.3s ease;
  color: var(--text-highlight);
}

.faq-item.active .faq-question svg {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 1.5rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 300px;
  padding: 0 1.5rem 1.5rem;
}

/* ==========================================================================
   核心任务 2：页脚 PBN 权重精准输血管道 样式
   ========================================================================== */
.footer {
  background: #030712;
  border-top: 1px solid var(--border-color);
  padding: 60px 0 30px;
  margin-top: 80px;
  position: relative;
  text-align: center;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.2rem;
  font-weight: 800;
}

.footer-desc {
  color: var(--text-muted);
  font-size: 0.9rem;
  max-width: 600px;
}

/* 友情链接/PBN 权重链接区 (符合低调美观小字号要求) */
.pbn-links-area {
  margin-top: 1.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  font-size: 0.8rem;
  color: #64748b;
  flex-wrap: wrap;
}

.pbn-links-title {
  color: #475569;
  font-size: 0.75rem;
  letter-spacing: 0.5px;
}

.pbn-link {
  color: #94a3b8;
  text-decoration: none;
  font-size: 0.8rem;
  transition: var(--transition);
  padding: 2px 6px;
  border-radius: 4px;
}

.pbn-link:hover {
  color: #38bdf8;
  background: rgba(56, 189, 248, 0.08);
}

.copyright {
  color: #475569;
  font-size: 0.8rem;
  margin-top: 1rem;
}

/* ==========================================================================
   响应式适配 (Responsive)
   ========================================================================== */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.2rem;
  }
  .hero p {
    font-size: 1rem;
  }
  .nav-links {
    display: none;
  }
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  .speed-monitor-card {
    padding: 1rem;
  }
  .speed-table th, .speed-table td {
    padding: 0.75rem 0.5rem;
    font-size: 0.85rem;
  }
}