/* ==========================================================================
   酷酷云机场 (KuKuYun Airport) 官方品牌落地页与文章站 样式系统
   设计亮点：浅色纯净极简风格 + 细字体 (Thin Typography) + 霓虹渐变光影 + 动态流光按钮
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@200;300;400;500;600&family=Noto+Sans+SC:wght@200;300;400;500;600&display=swap');

:root {
  /* 品牌核心色彩 - 纯净浅色基调与霓虹色系 (Neon Palette) */
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --bg-subtle: #f1f5f9;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --border-light: #e2e8f0;
  --border-hover: #cbd5e1;

  /* 霓虹色系 Accent Colors */
  --neon-cyan: #00f3ff;
  --neon-blue: #3b82f6;
  --neon-indigo: #6366f1;
  --neon-violet: #8a2be2;
  --neon-pink: #ec4899;

  /* 霓虹渐变 */
  --gradient-neon: linear-gradient(135deg, #00f3ff 0%, #6366f1 50%, #8a2be2 100%);
  --gradient-neon-hover: linear-gradient(135deg, #38bdf8 0%, #818cf8 50%, #c084fc 100%);
  --gradient-hero-neon: linear-gradient(135deg, #090d16 0%, #0f172a 40%, #1e1b4b 100%);
  --gradient-light-card: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);

  /* 阴影 & 发光 */
  --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.04);
  --shadow-md: 0 8px 24px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 16px 36px rgba(15, 23, 42, 0.08);
  --neon-glow: 0 0 25px rgba(0, 243, 255, 0.35), 0 4px 15px rgba(99, 102, 241, 0.25);
  --neon-glow-strong: 0 0 35px rgba(0, 243, 255, 0.6), 0 8px 25px rgba(138, 43, 226, 0.4);

  /* 细字体与排版规范 */
  --font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

/* 基础重置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-main);
  color: var(--text-primary);
  font-weight: 300; /* 细字体排版 */
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

a:hover {
  color: var(--neon-violet);
}

ul, ol {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* 布局容器 */
.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

/* 细字体标题通用规范 */
h1, h2, h3, h4, h5, h6 {
  font-weight: 300; /* 极简细字体 */
  letter-spacing: -0.01em;
  color: var(--text-primary);
  line-height: 1.3;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(99, 102, 241, 0.08);
  border: 1px solid rgba(0, 243, 255, 0.2);
  border-radius: var(--radius-full);
  color: #4f46e5;
  font-size: 0.85rem;
  font-weight: 400;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: 16px;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 300;
  text-align: center;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  font-weight: 300;
  text-align: center;
  max-width: 700px;
  margin: 0 auto 48px auto;
}

/* 动态霓虹发光按钮 */
.btn-neon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 32px;
  background: var(--gradient-neon);
  background-size: 200% auto;
  color: #ffffff !important;
  font-size: 1rem;
  font-weight: 400;
  letter-spacing: 0.02em;
  border-radius: var(--radius-full);
  box-shadow: var(--neon-glow);
  border: none;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: var(--transition);
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

.btn-neon::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(
    60deg,
    transparent 30%,
    rgba(255, 255, 255, 0.35) 50%,
    transparent 70%
  );
  transform: rotate(30deg) translateX(-100%);
  transition: transform 0.8s ease;
}

.btn-neon:hover {
  background-position: right center;
  box-shadow: var(--neon-glow-strong);
  transform: translateY(-2px);
}

.btn-neon:hover::after {
  transform: rotate(30deg) translateX(100%);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  background: #ffffff;
  color: var(--text-primary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-full);
  font-size: 0.95rem;
  font-weight: 400;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  border-color: var(--neon-indigo);
  color: var(--neon-indigo);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.12);
}

/* 导航栏 (Sticky Header with Glassmorphism) */
.header {
  position: sticky;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(226, 232, 240, 0.8);
  transition: var(--transition);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.35rem;
  font-weight: 400;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.brand-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, #00f3ff 0%, #6366f1 100%);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  font-weight: 600;
  font-size: 1.1rem;
  box-shadow: 0 0 15px rgba(0, 243, 255, 0.4);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-weight: 300;
  padding: 6px 0;
  position: relative;
}

.nav-link:hover, .nav-link.active {
  color: var(--neon-indigo);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-neon);
  transition: width 0.3s ease;
  border-radius: 2px;
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* 首屏 (Hero Banner - 纯白底色 + 极简细字体 + 动态发光按钮) */
.hero {
  position: relative;
  padding: 90px 0 100px 0;
  background: #ffffff;
  color: var(--text-primary);
  overflow: hidden;
  border-bottom: 1px solid var(--border-light);
}

.hero-backdrop {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  background: 
    radial-gradient(circle at 20% 20%, rgba(0, 243, 255, 0.07) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(138, 43, 226, 0.07) 0%, transparent 50%),
    radial-gradient(circle at 50% 40%, rgba(99, 102, 241, 0.05) 0%, transparent 60%);
}

.hero-grid-overlay {
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(15, 23, 42, 0.04) 1px, transparent 1px);
  background-size: 32px 32px;
  opacity: 0.6;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 860px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  background: rgba(99, 102, 241, 0.06);
  border: 1px solid rgba(0, 243, 255, 0.25);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-full);
  font-size: 0.88rem;
  color: #4f46e5;
  font-weight: 400;
  margin-bottom: 24px;
}

.hero-badge-dot {
  width: 8px;
  height: 8px;
  background: var(--neon-cyan);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--neon-cyan);
  animation: pulse 2s infinite;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 200; /* 超细精致字体 */
  line-height: 1.18;
  letter-spacing: -0.02em;
  margin-bottom: 20px;
  color: var(--text-primary);
}

.hero-title span {
  background: linear-gradient(135deg, #0f172a 30%, #6366f1 70%, #8a2be2 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 300;
}

.hero-subtitle {
  font-size: 1.25rem;
  font-weight: 300;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 36px;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  margin-bottom: 48px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  padding-top: 36px;
  border-top: 1px solid var(--border-light);
}

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

.stat-number {
  font-size: 1.85rem;
  font-weight: 300;
  color: var(--text-primary);
  margin-bottom: 4px;
  background: linear-gradient(135deg, #6366f1 0%, #8a2be2 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 300;
}

/* 通用Section */
.section {
  padding: 80px 0;
}

.section-alt {
  background-color: var(--bg-card);
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

/* 卡片与网格 */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  position: relative;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: rgba(99, 102, 241, 0.4);
  box-shadow: 0 12px 30px rgba(0, 243, 255, 0.1);
}

.feature-icon {
  width: 52px;
  height: 52px;
  background: rgba(99, 102, 241, 0.06);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--neon-indigo);
  margin-bottom: 20px;
  border: 1px solid rgba(0, 243, 255, 0.15);
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 400;
  margin-bottom: 12px;
}

.feature-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-weight: 300;
  line-height: 1.65;
}

/* 套餐卡片 */
.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  position: relative;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.pricing-card.featured {
  border-color: var(--neon-indigo);
  box-shadow: 0 12px 36px rgba(99, 102, 241, 0.15), 0 0 20px rgba(0, 243, 255, 0.15);
}

.pricing-card.featured::before {
  content: '热门推荐';
  position: absolute;
  top: -14px;
  right: 28px;
  background: var(--gradient-neon);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 400;
  padding: 4px 14px;
  border-radius: var(--radius-full);
  box-shadow: 0 4px 10px rgba(99, 102, 241, 0.3);
}

.pricing-header {
  margin-bottom: 24px;
  text-align: center;
}

.pricing-name {
  font-size: 1.35rem;
  font-weight: 400;
  margin-bottom: 8px;
}

.pricing-price {
  font-size: 2.75rem;
  font-weight: 200;
  color: var(--text-primary);
  line-height: 1;
  margin-bottom: 8px;
}

.pricing-price span {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: 300;
}

.pricing-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
  font-weight: 300;
}

.pricing-features {
  margin: 24px 0 32px 0;
  flex-grow: 1;
}

.pricing-feature-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.92rem;
  color: var(--text-secondary);
  font-weight: 300;
  margin-bottom: 12px;
}

.pricing-feature-item svg {
  color: var(--neon-indigo);
  flex-shrink: 0;
}

/* 节点测速表格卡片 */
.speed-test-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  overflow-x: auto;
}

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

.speed-table th {
  padding: 14px 18px;
  font-weight: 400;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-light);
  font-size: 0.9rem;
}

.speed-table td {
  padding: 16px 18px;
  font-weight: 300;
  border-bottom: 1px solid var(--bg-subtle);
  font-size: 0.92rem;
}

.badge-tag {
  display: inline-block;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 0.78rem;
  font-weight: 400;
}

.badge-green {
  background: rgba(16, 185, 129, 0.1);
  color: #059669;
}

.badge-blue {
  background: rgba(59, 130, 246, 0.1);
  color: #2563eb;
}

.badge-purple {
  background: rgba(168, 85, 247, 0.1);
  color: #9333ea;
}

/* FAQ Accordion */
.faq-grid {
  max-width: 840px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

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

.faq-question {
  padding: 20px 24px;
  font-size: 1.05rem;
  font-weight: 400;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  user-select: none;
}

.faq-answer {
  padding: 0 24px 20px 24px;
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-weight: 300;
  line-height: 1.7;
}

/* 文章与教程卡片 */
.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
  height: 100%;
}

.article-card:hover {
  border-color: var(--neon-indigo);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.article-category {
  font-size: 0.8rem;
  color: var(--neon-indigo);
  font-weight: 400;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.article-card-title {
  font-size: 1.15rem;
  font-weight: 400;
  line-height: 1.4;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.article-card-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-weight: 300;
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  color: var(--text-muted);
  font-weight: 300;
  padding-top: 14px;
  border-top: 1px solid var(--bg-subtle);
}

/* 页脚 Footer */
.footer {
  background: #090d16;
  color: #94a3b8;
  padding: 70px 0 30px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 40px;
  margin-bottom: 50px;
}

.footer-brand-title {
  font-size: 1.35rem;
  color: #ffffff;
  font-weight: 300;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.footer-brand-desc {
  font-size: 0.9rem;
  color: #64748b;
  font-weight: 300;
  line-height: 1.7;
  max-width: 320px;
}

.footer-column-title {
  font-size: 1rem;
  color: #ffffff;
  font-weight: 400;
  margin-bottom: 20px;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-link {
  color: #94a3b8;
  font-size: 0.9rem;
  font-weight: 300;
}

.footer-link:hover {
  color: var(--neon-cyan);
}

.footer-bottom {
  padding-top: 30px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: #64748b;
  font-weight: 300;
}

/* 文章详情页专用排版 */
.article-page {
  padding: 60px 0;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--text-muted);
  font-weight: 300;
  margin-bottom: 32px;
}

.article-header {
  margin-bottom: 40px;
  text-align: left;
}

.article-title-main {
  font-size: 2.5rem;
  font-weight: 300;
  line-height: 1.25;
  margin-bottom: 18px;
}

.article-header-meta {
  display: flex;
  align-items: center;
  gap: 20px;
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 300;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-light);
}

.article-content {
  font-size: 1.05rem;
  line-height: 1.85;
  color: #334155;
  font-weight: 300;
  max-width: 840px;
}

.article-content h2 {
  font-size: 1.75rem;
  font-weight: 300;
  margin: 40px 0 20px 0;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-light);
  color: var(--text-primary);
}

.article-content h3 {
  font-size: 1.35rem;
  font-weight: 400;
  margin: 30px 0 16px 0;
  color: var(--text-primary);
}

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

.article-content ul, .article-content ol {
  margin: 0 0 24px 24px;
}

.article-content li {
  margin-bottom: 10px;
  list-style-type: disc;
}

.article-cta-box {
  background: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
  border-radius: var(--radius-lg);
  padding: 36px;
  color: #ffffff;
  text-align: center;
  margin: 48px 0;
  position: relative;
  overflow: hidden;
  box-shadow: 0 16px 36px rgba(15, 23, 42, 0.15);
}

.article-cta-title {
  font-size: 1.6rem;
  font-weight: 300;
  margin-bottom: 12px;
  color: #ffffff;
}

.article-cta-desc {
  font-size: 0.98rem;
  color: #cbd5e1;
  font-weight: 300;
  margin-bottom: 24px;
}

.related-box {
  margin-top: 60px;
  padding-top: 40px;
  border-top: 1px solid var(--border-light);
}

/* 响应式适配 Responsive */
@media (max-width: 1024px) {
  .hero-title {
    font-size: 2.75rem;
  }
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .header-container {
    height: 64px;
  }
  .nav-links {
    display: none; /* 可后续拓展移动端抽屉导航 */
  }
  .hero {
    padding: 60px 0 70px 0;
  }
  .hero-title {
    font-size: 2.1rem;
  }
  .hero-subtitle {
    font-size: 1.05rem;
  }
  .hero-stats {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
  }
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }
}