/* ==========================================================================
   一分机场 (YiFenJiChang) - 纯 CSS3 浅色主题样式表
   特点：极致轻量、超快加载、现代明亮视觉、全端响应式适配
   ========================================================================== */

/* 1. 全局变量与 Reset */
:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --secondary: #4f46e5;
  --accent: #0ea5e9;
  --accent-light: #f0f9ff;
  --success: #10b981;
  --warning: #f59e0b;
  
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --bg-subtle: #f1f5f9;
  
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-light: #64748b;
  
  --border-color: #e2e8f0;
  --border-focus: #93c5fd;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.06), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --shadow-lg: 0 10px 25px -5px rgba(37, 99, 235, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.02);
  --shadow-hover: 0 20px 30px -10px rgba(37, 99, 235, 0.15);
  
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --max-width: 1200px;
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
}

*, *::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-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: all 0.2s ease;
}

a:hover {
  color: var(--primary-hover);
}

ul, ol {
  list-style: none;
}

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

/* 2. 通用组件 */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 80px 0;
}

.section-title {
  text-align: center;
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
  letter-spacing: -0.02em;
}

.section-subtitle {
  text-align: center;
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto 50px auto;
}

.gradient-text {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* 3. 按钮 (CTA Buttons) */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 32px;
  font-size: 1rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer;
  border: none;
  outline: none;
  min-height: 48px;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  color: #ffffff !important;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.45);
  color: #ffffff;
}

.btn-secondary {
  background-color: var(--bg-card);
  color: var(--text-main) !important;
  border: 2px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  border-color: var(--primary);
  color: var(--primary) !important;
  background-color: var(--primary-light);
  transform: translateY(-2px);
}

.btn-block {
  width: 100%;
}

.badge {
  display: inline-block;
  padding: 4px 12px;
  font-size: 0.8125rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  background-color: var(--primary-light);
  color: var(--primary);
  margin-bottom: 16px;
}

/* 4. 导航栏 (Header / Navbar) */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  height: 72px;
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-main);
}

.logo-icon {
  width: 38px;
  height: 38px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: white;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.25);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-links a {
  color: var(--text-muted);
  font-weight: 600;
  font-size: 0.95rem;
}

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

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

/* 5. Hero 主视觉区 */
.hero {
  padding: 90px 0 70px 0;
  background: radial-gradient(circle at 50% 0%, #eff6ff 0%, var(--bg-main) 70%);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero-title {
  font-size: 3.25rem;
  font-weight: 900;
  line-height: 1.25;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  color: var(--text-main);
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 760px;
  margin: 0 auto 36px auto;
  line-height: 1.7;
}

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

.hero-highlights {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 28px;
  color: var(--text-light);
  font-size: 0.9rem;
  font-weight: 500;
  flex-wrap: wrap;
}

.hero-highlights span {
  display: flex;
  align-items: center;
  gap: 6px;
}

.hero-highlights span::before {
  content: "✓";
  color: var(--success);
  font-weight: bold;
}

/* 6. 核心优势 (Features) */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}

.feature-card {
  background: var(--bg-card);
  padding: 36px 28px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-md);
  transition: all 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
  border-color: var(--border-focus);
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background-color: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-main);
}

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

/* 7. 流媒体与 AI 支持 (Streaming & AI) */
.unlock-section {
  background-color: var(--bg-card);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.unlock-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
}

.unlock-box {
  background: var(--bg-main);
  padding: 36px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.unlock-box h3 {
  font-size: 1.35rem;
  font-weight: 800;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.unlock-box p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 24px;
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.tag-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-main);
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  gap: 8px;
}

/* 8. 套餐价格表 (Pricing Table) */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
  align-items: stretch;
}

.price-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  padding: 40px 32px;
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all 0.3s ease;
}

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

.price-card.popular {
  border: 2px solid var(--primary);
  box-shadow: var(--shadow-lg);
}

.popular-ribbon {
  position: absolute;
  top: -14px;
  right: 24px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  color: white;
  font-size: 0.8125rem;
  font-weight: 700;
  padding: 4px 16px;
  border-radius: var(--radius-full);
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.3);
}

.price-header {
  margin-bottom: 24px;
}

.price-name {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 8px;
}

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

.price-amount {
  font-size: 2.75rem;
  font-weight: 900;
  color: var(--text-main);
  margin-bottom: 24px;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.price-amount span {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-light);
}

.price-features {
  margin-bottom: 32px;
  flex-grow: 1;
}

.price-features li {
  padding: 10px 0;
  color: var(--text-muted);
  font-size: 0.9375rem;
  border-bottom: 1px dashed var(--border-color);
  display: flex;
  align-items: center;
  gap: 10px;
}

.price-features li:last-child {
  border-bottom: none;
}

.price-features li::before {
  content: "✓";
  color: var(--success);
  font-weight: bold;
}

/* 9. 用户评价 (Testimonials) */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

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

.stars {
  color: #f59e0b;
  margin-bottom: 12px;
  font-size: 1rem;
}

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

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

.user-avatar {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, #cbd5e1 0%, #94a3b8 100%);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
}

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

.user-details p {
  font-size: 0.8125rem;
  color: var(--text-light);
}

/* 10. 常见问题 (FAQ) */
.faq-container {
  max-width: 800px;
  margin: 0 auto;
}

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

.faq-item:hover {
  border-color: var(--border-focus);
}

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

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

.faq-item summary::after {
  content: "+";
  font-size: 1.5rem;
  font-weight: 400;
  color: var(--text-light);
  transition: transform 0.2s ease;
}

.faq-item[open] summary::after {
  content: "−";
}

.faq-answer {
  padding: 0 24px 20px 24px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
  border-top: 1px solid var(--bg-subtle);
  padding-top: 16px;
}

/* 11. 精简页脚 (Footer) - 按照要求只保留4个新页面打开的标题 */
.footer {
  background-color: var(--bg-card);
  border-top: 1px solid var(--border-color);
  padding: 40px 0;
  text-align: center;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 36px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.footer-nav a {
  color: var(--text-muted);
  font-weight: 600;
  font-size: 0.95rem;
}

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

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

/* 12. 子页面专用通用样式 (About, Terms, Privacy, Sitemap) */
.page-header {
  background: radial-gradient(circle at 50% 0%, #eff6ff 0%, var(--bg-main) 100%);
  padding: 60px 0 40px 0;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
}

.page-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
}

.page-subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
}

.content-body {
  background: var(--bg-card);
  padding: 40px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  margin: 40px 0;
}

.content-body h2 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-main);
  margin: 28px 0 12px 0;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
}

.content-body h2:first-child {
  margin-top: 0;
}

.content-body p {
  color: var(--text-muted);
  margin-bottom: 16px;
  line-height: 1.8;
}

.content-body ul {
  margin-bottom: 20px;
  padding-left: 20px;
}

.content-body ul li {
  list-style-type: disc;
  color: var(--text-muted);
  margin-bottom: 8px;
  line-height: 1.7;
}

.sitemap-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 30px;
}

.sitemap-card {
  background: var(--bg-main);
  padding: 24px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.sitemap-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 14px;
  color: var(--primary);
}

.sitemap-card ul li {
  margin-bottom: 10px;
}

.sitemap-card ul li a {
  color: var(--text-main);
  font-weight: 500;
}

.sitemap-card ul li a:hover {
  color: var(--primary);
}

/* 13. 响应式适配 (@media Queries) */
@media (max-width: 992px) {
  .hero-title {
    font-size: 2.5rem;
  }
  
  .features-grid,
  .pricing-grid,
  .testimonials-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .unlock-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .section {
    padding: 50px 0;
  }
  
  .header {
    height: 64px;
  }
  
  .nav-links {
    display: none; /* 移动端隐藏中间冗余导航，保留核心 CTA */
  }

  .hero {
    padding: 50px 0 40px 0;
  }
  
  .hero-title {
    font-size: 2rem;
  }
  
  .hero-subtitle {
    font-size: 1.05rem;
  }
  
  .hero-cta {
    flex-direction: column;
    width: 100%;
  }
  
  .btn {
    width: 100%;
    padding: 14px 20px;
  }
  
  .features-grid,
  .pricing-grid,
  .testimonials-grid,
  .sitemap-grid,
  .tech-article-grid {
    grid-template-columns: 1fr;
  }

  .price-card.popular {
    transform: none;
  }

  .footer-nav {
    flex-direction: column;
    gap: 16px;
  }
  
  .content-body {
    padding: 24px;
  }
}

/* 高科技网格卡片 (High-Tech Grid Cards) 布局 */
.tech-article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin-top: 36px;
}

.tech-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 30px 24px;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-md);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

.tech-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--primary) 0%, var(--accent) 100%);
  opacity: 0;
  transition: opacity 0.3s ease;
}

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

.tech-card:hover::before {
  opacity: 1;
}

.card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.card-tag {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  background: var(--primary-light);
  color: var(--primary);
}

.card-date {
  font-size: 0.8125rem;
  color: var(--text-light);
}

.card-title {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.45;
  margin-bottom: 12px;
}

.card-title a {
  color: var(--text-main);
}

.card-title a:hover {
  color: var(--primary);
}

.card-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 20px;
  flex-grow: 1;
}

.card-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--primary);
  transition: gap 0.2s ease;
}

.card-link:hover {
  gap: 10px;
}

.return-bar {
  margin-bottom: 30px;
}