/* ==========================================================================
   MESL机场专线官网 - 原生精简高性能 CSS 样式表 (style.css)
   - 零依赖、纯原生、秒开级加载性能
   - 响应式自适应适配 (360px, 390px, 768px, 1440px)
   - 遵循 WCAG 2.1 AA 对比度与无障碍规范 (4.5:1+)
   - 触控区域 >= 44x44px, 锚点偏移 scroll-margin-top
   ========================================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --bg-primary: #0a0d14;
  --bg-secondary: #111625;
  --bg-card: #161d30;
  --bg-card-hover: #1e263d;
  --bg-accent: #0f172a;
  --border-color: #242f4d;
  --border-hover: #3b82f6;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-accent: #06b6d4;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-gold: #fbbf24;
  --max-width: 1200px;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --shadow-card: 0 4px 20px -2px rgba(0, 0, 0, 0.4);
  --shadow-hover: 0 10px 30px -5px rgba(37, 99, 235, 0.25);
  --nav-height: 72px;
}

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

html {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.6;
  scroll-behavior: smooth;
  text-rendering: optimizeLegibility;
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* 键盘无障碍跳链 (Skip link) */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--color-primary);
  color: #ffffff;
  padding: 0.75rem 1.5rem;
  font-weight: 700;
  border-radius: var(--radius-sm);
  z-index: 9999;
  text-decoration: none;
  transition: top 0.2s ease;
}
.skip-link:focus {
  top: 1rem;
  outline: 3px solid var(--color-accent);
}

/* 焦点高亮 (Accessibility Focus Outline) */
a:focus-visible, button:focus-visible, summary:focus-visible, input:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 3px;
}

/* 锚点防遮挡 */
section[id], article[id], div[id] {
  scroll-margin-top: calc(var(--nav-height) + 20px);
}

/* 通用容器 */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* 顶部导航栏 (Header / Nav) */
.site-header {
  position: sticky;
  top: 0;
  height: var(--nav-height);
  background-color: rgba(10, 13, 20, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  display: flex;
  align-items: center;
}

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-main);
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.brand-icon {
  width: 32px;
  height: 32px;
  color: var(--color-accent);
  fill: currentColor;
}

.nav-links {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 1.5rem;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.5rem 0.25rem;
  transition: color 0.2s ease;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.nav-links a:hover, .nav-links a.active {
  color: var(--color-accent);
}

/* 按钮规范 (CTA >= 44x44px) */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 44px;
  min-width: 44px;
  padding: 0.65rem 1.4rem;
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background-color 0.2s, transform 0.15s, box-shadow 0.2s;
  border: 1px solid transparent;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), #1d4ed8);
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #3b82f6, #2563eb);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.5);
}

.btn-accent {
  background: linear-gradient(135deg, var(--color-accent), #0891b2);
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(6, 182, 212, 0.35);
}

.btn-accent:hover {
  background: linear-gradient(135deg, #22d3ee, var(--color-accent));
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(6, 182, 212, 0.5);
}

.btn-outline {
  background: transparent;
  color: var(--text-main);
  border-color: var(--border-color);
}

.btn-outline:hover {
  border-color: var(--border-hover);
  background-color: rgba(59, 130, 246, 0.1);
  color: #ffffff;
}

.btn-lg {
  padding: 0.85rem 2rem;
  font-size: 1.05rem;
  font-weight: 700;
}

/* 主视觉区 (Hero Section) */
.hero-section {
  padding: 5rem 0 4rem;
  text-align: center;
  position: relative;
  background: radial-gradient(circle at 50% 20%, rgba(37, 99, 235, 0.15) 0%, transparent 60%);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(6, 182, 212, 0.12);
  border: 1px solid rgba(6, 182, 212, 0.3);
  color: var(--color-accent);
  padding: 0.35rem 0.9rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}

.hero-title {
  font-size: 2.75rem;
  line-height: 1.2;
  font-weight: 900;
  letter-spacing: -0.03em;
  margin-bottom: 1.25rem;
  background: linear-gradient(135deg, #ffffff 40%, #94a3b8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 1.25rem;
}

.hero-desc {
  max-width: 780px;
  margin: 0 auto 2.5rem;
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 3rem;
}

.hero-trust-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
  max-width: 900px;
  margin: 0 auto;
  padding: 1.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

.trust-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.trust-num {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text-main);
}

.trust-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* 区块通用结构 */
.section-padding {
  padding: 4.5rem 0;
}

.section-header {
  text-align: center;
  max-width: 750px;
  margin: 0 auto 3rem;
}

.section-tag {
  color: var(--color-accent);
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  display: inline-block;
  margin-bottom: 0.5rem;
}

.section-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.6;
}

/* 核心优势卡片 (3个图文卡片) */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 2rem;
  transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
  display: flex;
  flex-direction: column;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-hover);
  box-shadow: var(--shadow-hover);
}

.feature-icon-box {
  width: 56px;
  height: 56px;
  background: rgba(37, 99, 235, 0.15);
  border: 1px solid rgba(37, 99, 235, 0.3);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent);
  margin-bottom: 1.25rem;
}

.feature-icon-box svg {
  width: 28px;
  height: 28px;
  fill: currentColor;
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 0.75rem;
}

.feature-text {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.65;
  flex-grow: 1;
}

/* 流媒体与 AI 支持图卡 */
.unlock-wrapper {
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-card) 100%);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2.5rem;
  align-items: center;
}

.unlock-content h3 {
  font-size: 1.65rem;
  font-weight: 800;
  margin-bottom: 1rem;
}

.unlock-content p {
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 1.5rem;
}

.unlock-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.badge-tag {
  background: rgba(16, 185, 129, 0.15);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: var(--color-success);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 600;
}

.unlock-grid-visual {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}

.service-card {
  background: rgba(10, 13, 20, 0.6);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.2rem;
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.service-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: 800;
  color: #ffffff;
  flex-shrink: 0;
}

.icon-netflix { background: #E50914; }
.icon-youtube { background: #FF0000; }
.icon-openai  { background: #10A37F; }
.icon-claude  { background: #D97706; }

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

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

/* 价格对比表 (Semantic Table) */
.pricing-table-container {
  overflow-x: auto;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-card);
  box-shadow: var(--shadow-card);
  margin-bottom: 2rem;
}

.pricing-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 680px;
}

.pricing-table caption {
  caption-side: top;
  text-align: left;
  padding: 1rem 1.5rem;
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--text-dim);
  border-bottom: 1px solid var(--border-color);
}

.pricing-table th, .pricing-table td {
  padding: 1.2rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.pricing-table th {
  background: var(--bg-secondary);
  color: var(--text-main);
  font-weight: 700;
  font-size: 1rem;
}

.pricing-table tbody tr:hover {
  background: var(--bg-card-hover);
}

.plan-name {
  font-weight: 800;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.plan-badge {
  font-size: 0.75rem;
  background: var(--color-primary);
  color: #fff;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
}

.plan-price {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--color-accent);
}

.plan-price small {
  font-size: 0.85rem;
  font-weight: normal;
  color: var(--text-muted);
}

.feature-check {
  color: var(--color-success);
  font-weight: 700;
}

/* 用户评价 (Customer Reviews) */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
}

.review-stars {
  color: var(--color-gold);
  font-size: 1.1rem;
  margin-bottom: 0.75rem;
  letter-spacing: 2px;
}

.review-body {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
  flex-grow: 1;
  margin-bottom: 1.25rem;
}

.reviewer-info {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1rem;
}

.reviewer-avatar {
  width: 40px;
  height: 40px;
  background: var(--color-primary);
  color: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
}

.reviewer-name {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-main);
}

.reviewer-role {
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* FAQ 常见问题解答 (全部默认展开 details[open]) */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: 860px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color 0.2s;
}

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

.faq-question {
  padding: 1.2rem 1.5rem;
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 44px;
}

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

.faq-question::after {
  content: "▾";
  font-size: 1.2rem;
  color: var(--color-accent);
  transition: transform 0.2s;
}

.faq-item[open] .faq-question::after {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 1.5rem 1.25rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
  border-top: 1px dashed rgba(255, 255, 255, 0.08);
  padding-top: 1rem;
}

.faq-answer a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.faq-answer a:hover {
  color: #38bdf8;
}

/* 页脚 (Footer: 仅保留 4 个新开标题) */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 3.5rem 0 2rem;
  margin-top: auto;
}

.footer-nav-list {
  display: flex;
  justify-content: center;
  align-items: center;
  list-style: none;
  gap: 2.5rem;
  flex-wrap: wrap;
  margin-bottom: 2rem;
}

.footer-nav-list a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 1rem;
  font-weight: 600;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  transition: color 0.2s;
}

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

.footer-bottom {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.85rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1.5rem;
  line-height: 1.6;
}

/* 文章详情页与子页面样式 */
.page-header {
  padding: 3.5rem 0 2rem;
  text-align: center;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 3rem;
}

.breadcrumbs {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-bottom: 1rem;
}

.breadcrumbs a {
  color: var(--text-muted);
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--color-accent);
}

.article-container {
  max-width: 820px;
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
}

.article-body {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #cbd5e1;
}

.article-body h2 {
  font-size: 1.65rem;
  color: var(--text-main);
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
}

.article-body h3 {
  font-size: 1.3rem;
  color: var(--text-main);
  margin: 1.8rem 0 0.8rem;
}

.article-body p {
  margin-bottom: 1.4rem;
}

.article-body ul, .article-body ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.article-body li {
  margin-bottom: 0.5rem;
}

.article-body a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
  font-weight: 600;
}

.article-body a:hover {
  color: #38bdf8;
}

.article-callout {
  background: rgba(37, 99, 235, 0.1);
  border-left: 4px solid var(--color-primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  transition: transform 0.2s, border-color 0.2s;
}

.article-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-hover);
}

.article-card-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

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

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

.article-card-meta {
  font-size: 0.8rem;
  color: var(--text-dim);
  margin-bottom: 0.75rem;
}

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

/* 响应式适配规范 (@media) */
@media (max-width: 1024px) {
  .features-grid, .reviews-grid, .article-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .unlock-wrapper {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  :root {
    --nav-height: 64px;
  }
  .hero-title {
    font-size: 2.1rem;
  }
  .hero-trust-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
  }
  .features-grid, .reviews-grid, .article-grid {
    grid-template-columns: 1fr;
  }
  .nav-links {
    display: none; /* 移动端精简无卡顿 */
  }
  .unlock-grid-visual {
    grid-template-columns: 1fr;
  }
  .footer-nav-list {
    flex-direction: column;
    gap: 1rem;
  }
  .section-padding {
    padding: 3rem 0;
  }
}

@media (max-width: 390px) {
  .hero-title {
    font-size: 1.8rem;
  }
  .hero-desc {
    font-size: 0.95rem;
  }
  .btn-lg {
    width: 100%;
  }
  .trust-num {
    font-size: 1.3rem;
  }
}

/* 动效友好性 (prefers-reduced-motion) */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}