/* 
 * 内联 CSS - 根据要求，所有样式内联，交付单一 HTML 文件
 * 配色方案：背景 #060D1F ｜ 主色 #22D3EE ｜ 点缀 #34D399
 */
:root {
  --primary: #22D3EE;
  --primary-hover: #0891B2;
  --bg: #060D1F;
  --bg-card: rgba(11, 22, 51, 0.65);
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --border: rgba(34, 211, 238, 0.25);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: radial-gradient(circle at center 70%, #0B1633 0%, #060D1F 80%);
  background-attachment: fixed;
  color: var(--text-main);
  line-height: 1.6;
}

a {
  color: var(--primary);
  text-decoration: none;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  padding: 20px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
  background-color: rgba(6, 13, 31, 0.5);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 100;
}

.logo {
  font-size: 24px;
  font-weight: bold;
  color: var(--text-main);
  text-shadow: 0 0 10px rgba(255,255,255,0.2);
  flex: 1;
}

.nav-links {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 25px;
  flex-wrap: wrap;
  flex: 2;
}

.header-action {
  flex: 1;
  display: flex;
  justify-content: flex-end;
}

.nav-links a {
  color: var(--text-main);
  font-weight: 500;
  transition: color 0.3s, text-shadow 0.3s;
}

.nav-links a:hover {
  color: var(--primary);
  text-shadow: 0 0 10px rgba(34, 211, 238, 0.8);
}

.nav-links a.btn {
  color: #060D1F;
  text-shadow: none;
}

.btn {
  display: inline-block;
  background-color: var(--primary);
  color: #060D1F;
  padding: 15px 30px;
  border-radius: 8px;
  font-size: 18px;
  font-weight: 600;
  transition: all 0.3s;
  text-align: center;
  box-shadow: 0 0 15px rgba(34, 211, 238, 0.4);
  border: 1px solid transparent;
}

.btn:hover {
  background-color: var(--primary-hover);
  color: #fff;
  box-shadow: 0 0 25px rgba(34, 211, 238, 0.8);
}

/* Legal Pages / Content */
.legal-page {
  padding: 60px 0;
  max-width: 800px;
  margin: 0 auto;
  background-color: var(--bg-card);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-radius: 12px;
  border: 1px solid var(--border);
  margin-top: 40px;
  padding: 40px;
}

.legal-page h1 {
  margin-bottom: 30px;
  text-align: center;
  text-shadow: 0 0 15px rgba(34, 211, 238, 0.3);
}

.legal-page h2 {
  margin: 40px 0 20px;
  color: var(--primary);
}

.legal-page p {
  color: var(--text-muted);
  margin-bottom: 15px;
}

/* Footer */
footer {
  background-color: rgba(6, 13, 31, 0.8);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  padding: 40px 0;
  border-top: 1px solid var(--border);
  text-align: center;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 30px;
  margin-bottom: 20px;
}

.footer-links a {
  color: var(--text-muted);
}

.footer-links a:hover {
  color: var(--text-main);
  text-shadow: 0 0 8px rgba(255,255,255,0.3);
}

.footer-copy {
  color: var(--text-muted);
  font-size: 14px;
}

/* Article Cards */
.article-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    margin-bottom: 50px;
}
.article-card {
    background-color: rgba(6, 13, 31, 0.5);
    border: 1px solid var(--border);
    padding: 25px;
    border-radius: 10px;
    transition: transform 0.3s, box-shadow 0.3s;
}
.article-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.4), 0 0 15px rgba(34, 211, 238, 0.2);
}
.article-card h3 {
    margin-bottom: 10px;
    font-size: 18px;
    line-height: 1.4;
}
.article-card p {
    font-size: 14px;
    margin-bottom: 0;
}

@media (max-width: 768px) {
  header {
    flex-direction: column;
    gap: 15px;
    padding: 15px 0;
  }
  .logo, .nav-links, .header-action {
    flex: none;
    width: 100%;
    justify-content: center;
    text-align: center;
  }
  .nav-links {
    gap: 15px;
  }
  .legal-page {
    margin-top: 20px;
    padding: 20px;
  }
  .article-grid {
      grid-template-columns: 1fr;
  }
}
    

/* Accessibility & Semantic Styles Added in Phase 2 */
:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 3px;
}
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.sr-only:focus {
  position: static;
  width: auto;
  height: auto;
  overflow: visible;
  clip: auto;
  white-space: normal;
  padding: 10px;
  background: var(--bg);
  color: var(--primary);
  z-index: 1000;
}
section, h1, h2, h3, h4, h5, h6, [id] {
  scroll-margin-top: 100px;
}
details.faq-item {
  background-color: var(--bg-card);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-radius: 8px;
  margin-bottom: 15px;
  border: 1px solid var(--border);
}
details.faq-item summary {
  font-size: 18px;
  padding: 20px;
  font-weight: bold;
  cursor: pointer;
  list-style: none;
  outline: none;
  color: var(--text-main);
}
details.faq-item summary::-webkit-details-marker {
  display: none;
}
details.faq-item summary:focus-visible {
  outline: 2px solid var(--primary);
  border-radius: 8px;
}
details.faq-item p {
  padding: 0 20px 20px 20px;
  margin: 0;
  color: var(--text-muted);
}
/* Table container for mobile scrolling */
.pricing-table-container {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  padding-top: 40px; padding-bottom: 40px;
}
.pricing-table { width: 100%; min-width: 900px; border-collapse: collapse; margin: 0; }
.pricing-table td { vertical-align: top; padding: 20px 15px; width: 33.33%; }