/* ===================================================================
   【风格 01 · 深海巨轮】Allblue 机场 (ALLBLUE)
   主配色：深海藏蓝 #06203B | 强调色：海光青 #38C6FF | 正文：纯白 #FFFFFF
   中文字体：思源黑体 Heavy / Noto Sans SC 900（超粗黑体） | 数字：Space Grotesk
   =================================================================== */

:root {
  --bg-ocean: #06203B;
  --bg-ocean-deep: #010a14;
  --bg-card: rgba(8, 36, 66, 0.72);
  --bg-card-hover: rgba(12, 48, 86, 0.88);
  
  --cyan-light: #38C6FF;
  --cyan-glow: rgba(56, 198, 255, 0.35);
  --cyan-dim: rgba(56, 198, 255, 0.12);
  --cyan-border: rgba(56, 198, 255, 0.22);
  --cyan-border-focus: rgba(56, 198, 255, 0.65);
  
  --text-white: #ffffff;
  --text-sub: #c8e4fc;
  --text-muted: #86abc7;
  --text-dark: #507796;
  
  --font-heading: "Noto Sans SC", "Source Han Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-number: 'Space Grotesk', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --max-width: 1220px;
  --transition: all 0.28s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-heading);
  background-color: var(--bg-ocean);
  color: var(--text-white);
  scroll-behavior: smooth;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  background-color: var(--bg-ocean);
  position: relative;
}

a {
  color: inherit;
  text-decoration: none;
}

img, svg {
  display: block;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* Header & Navigation */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(6, 32, 59, 0.88);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--cyan-border);
  padding: 16px 0;
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.35rem;
  font-weight: 900;
  letter-spacing: -0.5px;
  color: var(--text-white);
}

.brand-logo span {
  color: var(--text-white);
  text-shadow: 0 0 12px var(--cyan-glow);
}

.brand-badge {
  font-size: 0.72rem;
  font-weight: 800;
  background: var(--cyan-dim);
  color: var(--cyan-light);
  padding: 3px 9px;
  border-radius: var(--radius-full);
  border: 1px solid var(--cyan-border);
  letter-spacing: 0.5px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
  list-style: none;
}

.nav-links a {
  color: var(--text-sub);
  font-size: 0.94rem;
  font-weight: 600;
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--cyan-light);
  text-shadow: 0 0 8px var(--cyan-glow);
}

/* CTA Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 0.95rem;
  font-weight: 800;
  padding: 12px 26px;
  border-radius: var(--radius-full);
  transition: var(--transition);
  cursor: pointer;
  white-space: nowrap;
  border: 1px solid transparent;
  text-align: center;
}

.btn-primary {
  background: linear-gradient(135deg, #1fa5e6 0%, #38C6FF 100%);
  color: #031426;
  font-weight: 900;
  box-shadow: 0 4px 20px rgba(56, 198, 255, 0.45);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(56, 198, 255, 0.65);
  background: linear-gradient(135deg, #38C6FF 0%, #75d9ff 100%);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-outline {
  background: rgba(8, 36, 66, 0.6);
  color: var(--text-white);
  border: 1px solid var(--cyan-border);
  backdrop-filter: blur(8px);
}

.btn-outline:hover {
  background: var(--cyan-dim);
  border-color: var(--cyan-light);
  color: var(--cyan-light);
  box-shadow: 0 0 16px var(--cyan-glow);
}

.btn-sm {
  padding: 8px 20px;
  font-size: 0.88rem;
}

.btn-lg {
  padding: 16px 36px;
  font-size: 1.08rem;
}

.btn-block {
  width: 100%;
}

/* Section Common */
.section {
  padding: 80px 0;
  position: relative;
}

.section-alt {
  background: rgba(3, 19, 36, 0.45);
  border-top: 1px solid var(--cyan-border);
  border-bottom: 1px solid var(--cyan-border);
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 52px;
}

.section-tag {
  font-size: 0.84rem;
  font-weight: 900;
  letter-spacing: 2px;
  color: var(--cyan-light);
  margin-bottom: 12px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.section-tag::before, .section-tag::after {
  content: "~";
  color: var(--cyan-light);
}

.section-title {
  font-size: clamp(1.85rem, 3.4vw, 2.45rem);
  font-weight: 900;
  color: var(--text-white);
  margin-bottom: 16px;
  line-height: 1.25;
}

.section-desc {
  font-size: 1.02rem;
  color: var(--text-sub);
  line-height: 1.7;
}

/* Internal Pages Layout */
.page-container {
  max-width: 880px;
  margin: 40px auto 80px;
  padding: 42px;
  background: var(--bg-card);
  border: 1px solid var(--cyan-border);
  border-radius: var(--radius-lg);
  box-shadow: 0 12px 36px rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(12px);
}

.page-header {
  border-bottom: 1px solid var(--cyan-border);
  padding-bottom: 24px;
  margin-bottom: 32px;
}

.page-title {
  font-size: 2.2rem;
  font-weight: 900;
  color: var(--text-white);
  margin-bottom: 10px;
}

.page-meta {
  color: var(--text-muted);
  font-size: 0.9rem;
}

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

.content-block h2 {
  font-size: 1.4rem;
  font-weight: 900;
  color: var(--text-white);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.content-block h2::before {
  content: "";
  display: inline-block;
  width: 4px;
  height: 18px;
  background: var(--cyan-light);
  border-radius: 2px;
}

.content-block p, .content-block ul {
  color: var(--text-sub);
  font-size: 0.98rem;
  line-height: 1.8;
  margin-bottom: 14px;
}

.content-block ul {
  padding-left: 20px;
}

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

.content-highlight {
  background: var(--cyan-dim);
  border-left: 3px solid var(--cyan-light);
  padding: 16px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: #e2e8f0;
  margin: 18px 0;
  font-size: 0.95rem;
}

/* 文章专属 FAQ 与内链组件 */
.art-faq-section {
  margin-top: 36px;
  padding-top: 26px;
  border-top: 1px solid var(--cyan-border);
}

.art-faq-section h2 {
  font-size: 1.32rem;
  font-weight: 900;
  color: #fff;
  margin-bottom: 18px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.art-faq-section h2::before {
  content: "❓";
  font-size: 1rem;
}

.art-faq-item {
  background: rgba(6, 32, 59, 0.7);
  border: 1px solid var(--cyan-border);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
  transition: var(--transition);
}

.art-faq-item[open] {
  border-color: var(--cyan-border-focus);
  background: rgba(10, 42, 77, 0.85);
  box-shadow: 0 4px 16px rgba(0,0,0,0.3);
}

.art-faq-summary {
  padding: 16px 20px;
  font-size: 0.98rem;
  font-weight: 800;
  color: #fff;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  list-style: none;
  user-select: none;
}

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

.art-faq-icon {
  width: 18px;
  height: 18px;
  color: var(--cyan-light);
  transition: transform 0.25s ease;
  flex-shrink: 0;
}

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

.art-faq-answer {
  padding: 0 20px 18px;
  color: var(--text-sub);
  font-size: 0.94rem;
  line-height: 1.8;
}

/* 相关推荐内链组件 */
.related-links-box {
  background: linear-gradient(135deg, rgba(8, 48, 88, 0.6) 0%, rgba(6, 32, 59, 0.8) 100%);
  border: 1px solid var(--cyan-border);
  border-radius: var(--radius-md);
  padding: 22px 24px;
  margin: 32px 0 20px;
}

.related-links-box h3 {
  font-size: 1.05rem;
  font-weight: 900;
  color: var(--cyan-light);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.related-links-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-left: 0 !important;
}

.related-links-list li {
  margin-bottom: 0 !important;
  display: flex;
  align-items: center;
  gap: 8px;
}

.related-links-list li a {
  color: var(--text-sub);
  text-decoration: underline;
  text-underline-offset: 4px;
  font-size: 0.93rem;
  transition: var(--transition);
}

.related-links-list li a:hover {
  color: var(--cyan-light);
  text-shadow: 0 0 8px var(--cyan-glow);
}

/* Footer (严格只保留四个标题，在新页面打开) */
.footer {
  margin-top: auto;
  background-color: var(--bg-ocean-deep);
  border-top: 1px solid var(--cyan-border);
  padding: 42px 0 32px;
}

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

.footer-nav a {
  color: var(--text-sub);
  font-size: 0.98rem;
  font-weight: 700;
  transition: var(--transition);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
}

.footer-nav a:hover {
  color: var(--cyan-light);
  background: var(--cyan-dim);
  text-shadow: 0 0 8px var(--cyan-glow);
}

.footer-copyright {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.86rem;
}

/* Responsive Media Queries */
@media (max-width: 768px) {
  .header {
    padding: 14px 0;
  }
  .nav-links {
    display: none;
  }
  .page-container {
    padding: 24px 18px;
    margin: 20px 14px 50px;
  }
  .footer-nav {
    flex-direction: column;
    gap: 14px;
  }
  .footer-nav a {
    width: 100%;
    text-align: center;
    background: var(--cyan-dim);
    min-height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .btn,
  .btn-sm,
  .nav-action .btn {
    min-height: 44px;
    min-width: 44px;
  }
}

/* 无障碍跳转主要内容入口 (Skip Link) */
.skip-link {
  position: absolute;
  top: -100px;
  left: 16px;
  background: var(--cyan-light);
  color: #031426;
  font-weight: 900;
  padding: 12px 22px;
  border-radius: var(--radius-sm);
  z-index: 9999;
  text-decoration: none;
  transition: top 0.2s ease;
  box-shadow: 0 4px 20px rgba(56, 198, 255, 0.5);
  font-size: 0.95rem;
}

.skip-link:focus,
.skip-link:focus-visible {
  top: 16px;
  outline: 3px solid #ffffff;
  outline-offset: 2px;
}

/* 锚点防固定页眉遮挡 */
section[id],
div[id],
article[id] {
  scroll-margin-top: 86px;
}

/* 键盘焦点样式 (Focus Visible) */
a:focus-visible,
button:focus-visible,
summary:focus-visible,
.btn:focus-visible {
  outline: 2px solid var(--cyan-light);
  outline-offset: 3px;
  box-shadow: 0 0 12px var(--cyan-glow);
}

/* 尊重系统动效偏好 */
@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;
  }
}