/* ==========================================================================
   肥猫云 (FatCatCloud) - 极简落地页 CSS
   设计风格：极简白底 / 轻量互联网产品风 / 纯原生 CSS / 完美响应式
   ========================================================================== */

/* 全局重置与变量定义 */
:root {
  --bg-main: #ffffff;
  --bg-alt: #f9fafb;
  --bg-card: #ffffff;
  --border-color: #e5e7eb;
  --border-hover: #cbd5e1;
  
  --text-primary: #111827;
  --text-secondary: #4b5563;
  --text-muted: #9ca3af;
  
  --accent-black: #0f172a;
  --accent-primary: #2563eb;
  --accent-primary-hover: #1d4ed8;
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.06), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
  --shadow-hover: 0 20px 30px -10px rgba(0, 0, 0, 0.08);
  
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --transition-fast: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

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

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

/* 通用容器与布局 */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 96px 0;
  border-bottom: 1px solid #f1f5f9;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background-color: #eff6ff;
  color: var(--accent-primary);
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  margin-bottom: 16px;
  border: 1px solid #dbeafe;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.025em;
  line-height: 1.25;
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto 56px auto;
  text-align: center;
}

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

/* 按钮通用规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition-fast);
  border: 1px solid transparent;
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--accent-black);
  color: #ffffff;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  background-color: #1e293b;
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background-color: #ffffff;
  color: var(--text-primary);
  border-color: var(--border-color);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  background-color: #f8fafc;
  border-color: var(--border-hover);
  transform: translateY(-2px);
  color: var(--accent-primary);
}

.btn-accent {
  background-color: var(--accent-primary);
  color: #ffffff;
  box-shadow: var(--shadow-md);
}

.btn-accent:hover {
  background-color: var(--accent-primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* 顶栏 Header 导航 */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(229, 231, 235, 0.8);
  height: 72px;
  display: flex;
  align-items: center;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-primary);
  cursor: pointer;
  user-select: none;
}

.logo-cat-icon {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #0f172a;
  border-radius: var(--radius-sm);
  padding: 4px;
}

.logo-cat-icon svg {
  width: 28px;
  height: 28px;
  fill: none;
  stroke: #ffffff;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.logo-text span {
  color: var(--accent-primary);
  font-weight: 500;
  font-size: 0.875rem;
  margin-left: 4px;
}

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

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
}

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

.header-cta {
  display: flex;
  align-items: center;
  gap: 12px;
}

.header-cta .btn {
  padding: 8px 18px;
  font-size: 0.875rem;
}

/* 主视觉区 Hero Section */
.hero {
  padding: 80px 0 100px 0;
  background: radial-gradient(circle at 80% 20%, rgba(37, 99, 235, 0.03) 0%, transparent 50%),
              radial-gradient(circle at 10% 90%, rgba(15, 23, 42, 0.02) 0%, transparent 50%);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 60px;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background-color: #f1f5f9;
  border: 1px solid #e2e8f0;
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 24px;
}

.hero-badge-pulse {
  width: 8px;
  height: 8px;
  background-color: var(--accent-emerald);
  border-radius: 50%;
  box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7);
  animation: pulse-green 2s infinite;
}

@keyframes pulse-green {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7); }
  70% { transform: scale(1); box-shadow: 0 0 0 8px rgba(16, 185, 129, 0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

.hero-title {
  font-size: 3.25rem;
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  margin-bottom: 20px;
}

.hero-title-cat {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--accent-black);
}

.hero-subtitle {
  font-size: 1.2rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 36px;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 32px;
}

.hero-features-list {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.hero-feature-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.hero-feature-item svg {
  width: 18px;
  height: 18px;
  color: var(--accent-emerald);
}

/* Hero 右侧动态卡片视觉 */
.hero-visual {
  position: relative;
  width: 100%;
}

.visual-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
}

.visual-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 20px;
  border-bottom: 1px solid #f1f5f9;
  margin-bottom: 24px;
}

.node-status-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

.status-pill {
  padding: 4px 10px;
  background-color: #ecfdf5;
  color: #047857;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
}

.speed-meter {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  margin-bottom: 24px;
}

.speed-val {
  font-size: 3rem;
  font-weight: 900;
  color: var(--accent-black);
  line-height: 1;
}

.speed-unit {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: 500;
  margin-left: 4px;
}

.ping-val {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--accent-emerald);
}

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

.node-item {
  background-color: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: var(--radius-md);
  padding: 12px;
  text-align: center;
  transition: var(--transition-fast);
}

.node-item:hover {
  border-color: var(--accent-primary);
  background-color: #ffffff;
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.node-flag {
  font-size: 1.25rem;
  margin-bottom: 4px;
}

.node-name {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-primary);
}

.node-ping {
  font-size: 0.75rem;
  color: var(--accent-emerald);
  font-weight: 600;
}

/* 核心优势区 */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.feature-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  transition: var(--transition-normal);
  box-shadow: var(--shadow-sm);
}

.feature-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.feature-icon-wrapper {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background-color: #f1f5f9;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  color: var(--accent-black);
}

.feature-card:hover .feature-icon-wrapper {
  background-color: var(--accent-black);
  color: #ffffff;
}

.feature-icon-wrapper svg {
  width: 28px;
  height: 28px;
}

.feature-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* 流媒体与 AI 支持区 */
.streaming-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 16px;
}

.streaming-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px 16px;
  text-align: center;
  transition: var(--transition-fast);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.streaming-card:hover {
  border-color: var(--accent-primary);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.streaming-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.1rem;
}

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

.streaming-card p {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* 套餐价格表 */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.pricing-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition-normal);
  box-shadow: var(--shadow-sm);
}

.pricing-card:hover {
  border-color: var(--accent-black);
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.pricing-card.popular {
  border: 2px solid var(--accent-black);
  box-shadow: var(--shadow-lg);
}

.popular-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background-color: var(--accent-black);
  color: #ffffff;
  padding: 4px 16px;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.pricing-header h3 {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.pricing-header p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.price-box {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 24px;
  padding-bottom: 20px;
  border-bottom: 1px solid #f1f5f9;
}

.currency {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.amount {
  font-size: 2.75rem;
  font-weight: 900;
  color: var(--text-primary);
  line-height: 1;
}

.period {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.pricing-features {
  list-style: none;
  margin-bottom: 32px;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.pricing-features li {
  font-size: 0.875rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.pricing-features li svg {
  width: 16px;
  height: 16px;
  color: var(--accent-emerald);
  flex-shrink: 0;
}

.pricing-card .btn {
  width: 100%;
}

/* 15 SEO 文章板块 */
.articles-section {
  background-color: #f9fafb;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.article-card {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition-normal);
  box-shadow: var(--shadow-sm);
}

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

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.article-tag {
  background-color: #f1f5f9;
  color: var(--accent-black);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.article-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.article-card p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 20px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--accent-primary);
}

.article-link svg {
  width: 16px;
  height: 16px;
  transition: var(--transition-fast);
}

.article-card:hover .article-link svg {
  transform: translateX(4px);
}

/* 用户评价 */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

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

.stars {
  color: #f59e0b;
  margin-bottom: 16px;
  font-size: 1rem;
}

.review-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 20px;
}

.reviewer {
  display: flex;
  align-items: center;
  gap: 12px;
}

.reviewer-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: #0f172a;
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.875rem;
}

.reviewer-info h4 {
  font-size: 0.9rem;
  font-weight: 700;
}

.reviewer-info p {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* FAQ 常见问题折叠面板 */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

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

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

.faq-icon {
  width: 20px;
  height: 20px;
  transition: var(--transition-fast);
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  padding: 0 24px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

.faq-item.active .faq-answer {
  max-height: 300px;
  padding-bottom: 20px;
}

/* 右侧章节切换悬浮按键 */
.floating-section-nav {
  position: fixed;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: 10px;
  background-color: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  padding: 8px 6px;
  box-shadow: var(--shadow-lg);
}

.floating-nav-btn {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  border: none;
  background-color: #f1f5f9;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-fast);
}

.floating-nav-btn:hover {
  background-color: var(--accent-black);
  color: #ffffff;
  transform: scale(1.1);
}

.floating-nav-btn:active {
  transform: scale(0.95);
}

.floating-nav-btn svg {
  width: 20px;
  height: 20px;
}

/* 页脚 Footer 规范 */
.footer {
  background-color: #0f172a;
  color: #f8fafc;
  padding: 64px 0 32px 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 40px;
  margin-bottom: 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid #1e293b;
}

.footer-col h4 {
  font-size: 1.1rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 20px;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-links a {
  color: #94a3b8;
  font-size: 0.9rem;
}

.footer-links a:hover {
  color: #ffffff;
}

/* 页脚居中版权与 PBN 外链 */
.footer-bottom {
  text-align: center;
  color: #64748b;
  font-size: 0.875rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.pbn-links-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  margin-top: 8px;
}

.pbn-link {
  color: #94a3b8;
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.pbn-link:hover {
  color: #38bdf8;
}

/* ==========================================================================
   响应式媒体查询 (Mobile & Tablet)
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .articles-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .streaming-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .header {
    height: 64px;
  }
  
  .nav-menu {
    display: none; /* 移动端精简 */
  }
  
  .hero-title {
    font-size: 2.25rem;
  }
  
  .hero-subtitle {
    font-size: 1rem;
  }
  
  .features-grid {
    grid-template-columns: 1fr;
  }
  
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  
  .articles-grid {
    grid-template-columns: 1fr;
  }
  
  .reviews-grid {
    grid-template-columns: 1fr;
  }
  
  .streaming-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
  }
  
  .floating-section-nav {
    right: 10px;
  }
  
  .btn {
    width: 100%;
    min-height: 48px;
  }
  
  .hero-cta-group {
    flex-direction: column;
    width: 100%;
  }
}