/* ===================================================================
   Allblue 机场 - 【风格 04 · 珊瑚速航】原生 CSS 样式库
   海底蓝 #052A4A | 珊瑚橙 #FF7A59 | 冷白正文 #F4F7FB
   中文字体 Noto Sans SC 900 | 数字 Space Grotesk
   =================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@700;900&family=Space+Grotesk:wght@600;700;800&display=swap');

:root {
  --bg-seabed: #052A4A;
  --bg-seabed-deep: #021627;
  --bg-card-coral: rgba(6, 42, 74, 0.72);
  --bg-card-hover: rgba(9, 56, 98, 0.85);
  --coral-orange: #FF7A59;
  --coral-orange-glow: rgba(255, 122, 89, 0.35);
  --coral-orange-light: #FFA188;
  --text-cold-white: #F4F7FB;
  --text-muted-marine: #93B5D1;
  --border-coral-subtle: rgba(255, 122, 89, 0.22);
  --border-coral-active: rgba(255, 122, 89, 0.65);
  --font-heading: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-digit: "Space Grotesk", -apple-system, BlinkMacSystemFont, sans-serif;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  --container-max: 1200px;
}

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

html {
  scroll-behavior: smooth;
  background-color: var(--bg-seabed);
  color: var(--text-cold-white);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  line-height: 1.65;
  position: relative;
  overflow-x: hidden;
  background: transparent;
}

#sea-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: 0;
  pointer-events: none;
  display: block;
}

header, main, footer {
  position: relative;
  z-index: 1;
}

a {
  color: inherit;
  text-decoration: none;
  transition: all 0.25s ease;
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 20px;
  padding-right: 20px;
}

/* 导航栏 */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  background-color: rgba(5, 42, 74, 0.88);
  border-bottom: 1px solid var(--border-coral-subtle);
}

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 900;
  letter-spacing: -0.5px;
  color: #fff;
}

.brand-logo .logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, #FF7A59 0%, #D44E2F 100%);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 16px var(--coral-orange-glow);
}

.brand-logo .logo-icon svg {
  width: 20px;
  height: 20px;
  fill: #fff;
}

.brand-logo .logo-highlight {
  color: var(--coral-orange);
  margin-left: 2px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 26px;
}

.nav-link {
  font-size: 0.95rem;
  color: var(--text-muted-marine);
  font-weight: 500;
  position: relative;
  padding: 4px 0;
}

.nav-link:hover {
  color: var(--coral-orange);
}

.nav-link.nav-highlight {
  color: var(--coral-orange);
  font-weight: 700;
}

.nav-link.nav-highlight::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--coral-orange);
  border-radius: 2px;
  box-shadow: 0 0 8px var(--coral-orange);
}

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

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 700;
  font-size: 0.95rem;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  white-space: nowrap;
  user-select: none;
  min-height: 44px;
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.88rem;
  min-height: 38px;
}

.btn-lg {
  padding: 15px 32px;
  font-size: 1.05rem;
  min-height: 52px;
}

.btn-primary {
  background: linear-gradient(135deg, #FF7A59 0%, #EA5834 100%);
  color: #fff;
  box-shadow: 0 4px 18px var(--coral-orange-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 26px rgba(255, 122, 89, 0.55);
  filter: brightness(1.08);
}

.btn-outline {
  background: rgba(255, 122, 89, 0.08);
  color: var(--text-cold-white);
  border: 1px solid var(--border-coral-subtle);
}

.btn-outline:hover {
  background: rgba(255, 122, 89, 0.18);
  border-color: var(--coral-orange);
  color: var(--coral-orange);
  transform: translateY(-2px);
}

/* 规范页脚 */
.footer {
  border-top: 1px solid var(--border-coral-subtle);
  background-color: var(--bg-seabed-deep);
  padding: 40px 0 35px;
  margin-top: 60px;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 36px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.footer-link {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-muted-marine);
  position: relative;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  transition: all 0.25s ease;
}

.footer-link:hover {
  color: var(--coral-orange);
  background: rgba(255, 122, 89, 0.12);
}

.footer-bottom {
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted-marine);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 20px;
}

/* 内容页面专属样式 */
.page-container {
  max-width: 900px;
  margin: 40px auto 80px;
  padding: 40px;
  background: var(--bg-card-coral);
  border: 1px solid var(--border-coral-subtle);
  border-radius: var(--radius-lg);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
}

.page-header {
  border-bottom: 1px solid rgba(255, 122, 89, 0.15);
  padding-bottom: 24px;
  margin-bottom: 32px;
}

.page-title {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: 900;
  margin-bottom: 8px;
  color: #fff;
}

.page-date {
  font-size: 0.85rem;
  color: var(--text-muted-marine);
}

.content-block {
  margin-bottom: 36px;
}

.content-block h2 {
  font-family: var(--font-heading);
  font-size: 1.45rem;
  font-weight: 900;
  margin-bottom: 16px;
  color: var(--coral-orange);
  display: flex;
  align-items: center;
  gap: 10px;
}

.content-block p {
  color: var(--text-cold-white);
  line-height: 1.8;
  margin-bottom: 16px;
  font-size: 1rem;
}

.content-block ul {
  list-style: disc;
  padding-left: 24px;
  color: var(--text-cold-white);
  line-height: 1.8;
  margin-bottom: 16px;
}

.content-block li {
  margin-bottom: 8px;
}

.highlight-box {
  background: rgba(255, 122, 89, 0.1);
  border-left: 4px solid var(--coral-orange);
  padding: 18px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 20px 0;
  color: #fff;
  font-size: 0.95rem;
}

.warning-box {
  background: rgba(239, 68, 68, 0.12);
  border-left: 4px solid #ef4444;
  padding: 18px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 20px 0;
  color: #fca5a5;
  font-size: 0.95rem;
}

.sitemap-group {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-top: 24px;
}

.sitemap-card {
  background: var(--bg-card-coral);
  border: 1px solid var(--border-coral-subtle);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: border-color 0.3s ease;
}

.sitemap-card:hover {
  border-color: var(--border-coral-active);
}

.sitemap-card h3 {
  font-family: var(--font-heading);
  font-size: 1.18rem;
  font-weight: 900;
  margin-bottom: 18px;
  color: var(--coral-orange);
  display: flex;
  align-items: center;
  gap: 8px;
}

.sitemap-card ul {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

.sitemap-card li {
  margin-bottom: 12px;
}

.sitemap-card li:last-child {
  margin-bottom: 0;
}

.sitemap-card a {
  color: var(--text-muted-marine);
  font-size: 0.95rem;
  line-height: 1.6;
  text-decoration: none;
  display: block;
  transition: all 0.2s ease;
}

.sitemap-card a:hover {
  color: var(--coral-orange);
  transform: translateX(4px);
}

/* 结构化 sitemap 链接行 */
.sitemap-link-row {
  display: flex;
  align-items: baseline;
  gap: 8px;
  text-decoration: none;
  color: var(--text-muted-marine);
  line-height: 1.6;
  transition: all 0.2s ease;
}

.sitemap-link-row:hover {
  color: #fff;
  transform: translateX(4px);
}

.sitemap-link-row:hover .sitemap-title {
  color: var(--coral-orange);
}

.sitemap-title {
  font-weight: 700;
  color: #fff;
  white-space: nowrap;
  flex-shrink: 0;
}

.sitemap-desc {
  font-size: 0.88rem;
  color: var(--text-muted-marine);
}

/* 9大知识科普文章索引网格 (Sitemap 3x3 专栏索引) */
.sitemap-article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 14px;
}

.sitemap-article-item {
  background: rgba(255, 122, 89, 0.05);
  border: 1px solid var(--border-coral-subtle);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  text-decoration: none;
  transition: all 0.2s ease;
}

.sitemap-article-item:hover {
  background: rgba(255, 122, 89, 0.12);
  border-color: var(--border-coral-active);
  transform: translateY(-2px);
}

.sitemap-article-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.sitemap-article-badge {
  font-family: var(--font-digit);
  font-size: 0.85rem;
  font-weight: 800;
  color: var(--coral-orange);
}

.sitemap-article-tag {
  font-size: 0.72rem;
  font-weight: 700;
  padding: 1px 6px;
  border-radius: 4px;
  background: rgba(255, 122, 89, 0.15);
  color: var(--coral-orange-light);
}

.sitemap-article-title {
  font-size: 0.90rem;
  font-weight: 700;
  color: #fff;
  line-height: 1.45;
  transition: color 0.2s ease;
}

.sitemap-article-item:hover .sitemap-article-title {
  color: var(--coral-orange);
}

@media (max-width: 1024px) {
  .sitemap-article-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .navbar .nav-menu {
    display: none;
  }
  .page-container {
    padding: 24px 18px;
    margin: 20px auto 50px;
  }
  .sitemap-group {
    grid-template-columns: 1fr;
  }
  .sitemap-article-grid {
    grid-template-columns: 1fr;
  }
  .sitemap-link-row {
    flex-direction: column;
    gap: 2px;
  }
  .footer-nav {
    flex-direction: column;
    gap: 12px;
  }
}

/* ===================================================================
   文章专属 FAQ 问答与相关内链区块设计
   =================================================================== */
.article-faq-section {
  margin-top: 30px;
  padding-top: 22px;
  border-top: 1px solid rgba(255, 122, 89, 0.22);
}

.faq-section-title {
  font-family: var(--font-heading);
  font-size: 1.20rem;
  font-weight: 900;
  color: var(--coral-orange);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.article-faq-item {
  background: rgba(255, 255, 255, 0.025);
  border: 1px solid var(--border-coral-subtle);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  margin-bottom: 12px;
  transition: all 0.2s ease;
}

.article-faq-item:hover {
  background: rgba(255, 122, 89, 0.08);
  border-color: var(--border-coral-active);
}

.article-faq-q {
  font-size: 0.98rem;
  font-weight: 800;
  color: #fff;
  margin-bottom: 6px;
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.article-faq-q-badge {
  font-family: var(--font-digit);
  color: var(--coral-orange);
  font-weight: 900;
  font-size: 1.05rem;
  flex-shrink: 0;
}

.article-faq-a {
  font-size: 0.90rem;
  color: var(--text-muted-marine);
  line-height: 1.65;
  margin: 0;
}

.article-related-links {
  margin-top: 22px;
  padding: 12px 16px;
  background: rgba(255, 122, 89, 0.06);
  border-left: 3px solid var(--coral-orange);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.88rem;
  color: var(--text-muted-marine);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 14px;
}

.article-related-links strong {
  color: #fff;
}

.article-related-links a {
  color: var(--coral-orange);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.2s ease;
}

.article-related-links a:hover {
  color: #fff;
}

/* ===================================================================
   无障碍与交互增强规范 (WCAG 2.1 & 移动端体验)
   =================================================================== */

/* 1. 跳过导航入口 (Skip Link) */
.skip-link {
  position: absolute;
  top: -120px;
  left: 20px;
  background: var(--coral-orange);
  color: #fff;
  padding: 12px 22px;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.95rem;
  z-index: 99999;
  text-decoration: none;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.45);
  transition: top 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}
.skip-link:focus,
.skip-link:focus-visible {
  top: 16px;
  outline: 3px solid #fff;
  outline-offset: 2px;
}

/* 2. 键盘焦点轮廓 (:focus-visible) */
a:focus-visible,
button:focus-visible,
summary:focus-visible,
input:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--coral-orange) !important;
  outline-offset: 3px !important;
  border-radius: 4px;
}

/* 3. 固定吸顶导航防遮挡 (scroll-margin-top) */
section[id],
div[id],
article[id],
h1[id],
h2[id],
h3[id],
.article-modal-backdrop,
.faq-item {
  scroll-margin-top: 88px;
}

/* 4. 移动端触控目标最低 44×44 CSS 像素保证 */
@media (max-width: 768px) {
  .btn,
  .btn-sm,
  .btn-primary,
  .btn-outline {
    min-height: 44px !important;
    min-width: 44px !important;
    display: inline-flex !important;
    align-items: center !important;
    justify-content: center !important;
  }
  .footer-link {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    padding: 10px 14px;
  }
  .nav-link {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
  }
}

/* 5. 遵循用户低动效偏好 (prefers-reduced-motion) */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  #sea-canvas {
    display: none !important;
  }
}