/* ---------------------------------------------------
   民航e行 · 静态展示页
   --------------------------------------------------- */

:root {
  --blue-900: #123B6B;
  --blue-700: #1F6FD1;
  --blue-600: #2E7CD6;
  --blue-500: #4C93E4;
  --blue-300: #9AC7F2;
  --blue-200: #C9E2F9;
  --blue-100: #E8F2FC;
  --blue-50:  #F5FAFF;

  --ink: #1F2D3D;
  --ink-soft: #59697C;
  --ink-faint: #8598AC;
  --white: #FFFFFF;
  --border: #DCEAFA;

  --shadow-sm: 0 2px 10px rgba(20, 60, 110, 0.06);
  --shadow-md: 0 10px 30px rgba(20, 60, 110, 0.10);

  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 10px;

  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
          "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

.container {
  width: 100%;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

em { font-style: normal; color: var(--blue-600); }

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 13px 30px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 600;
  white-space: nowrap;
  transition: transform .15s ease, box-shadow .15s ease, background-color .15s ease;
  cursor: pointer;
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--blue-600);
  color: var(--white);
  box-shadow: 0 8px 20px rgba(46, 124, 214, 0.28);
}
.btn-primary:hover { background: var(--blue-700); transform: translateY(-1px); }

.btn-ghost {
  background: var(--white);
  color: var(--blue-700);
  border-color: var(--blue-200);
}
.btn-ghost:hover { border-color: var(--blue-500); transform: translateY(-1px); }

.btn-sm { padding: 9px 20px; font-size: 14px; }

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  height: 68px;
  display: flex;
  align-items: center;
  gap: 20px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-right: auto;
}

.brand-mark { width: 34px; height: 34px; border-radius: 9px; }

.brand-name {
  font-size: 19px;
  font-weight: 700;
  letter-spacing: .2px;
}

.site-nav {
  display: flex;
  gap: 32px;
}

.site-nav a {
  font-size: 15px;
  color: var(--ink-soft);
  font-weight: 500;
}
.site-nav a:hover { color: var(--blue-600); }

/* ---------- Hero ---------- */

.hero {
  position: relative;
  overflow: hidden;
  padding: 76px 0 92px;
  background: linear-gradient(180deg, var(--blue-50) 0%, var(--white) 100%);
}

.hero-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  /* 两处柔光落在黄金分割交点（约 38% / 62%）：左托文案，右托配图 */
  background-image:
    radial-gradient(680px 360px at 38% 38%, rgba(79, 148, 224, 0.13), transparent 64%),
    radial-gradient(560px 320px at 70% 46%, rgba(79, 148, 224, 0.16), transparent 62%),
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='1200' height='500' viewBox='0 0 1200 500'%3E%3Cpath d='M-50 420 C 250 320, 420 480, 700 300 S 1150 120, 1300 160' stroke='%23BFDDF7' stroke-width='2' fill='none' stroke-dasharray='2 10' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: center;
}

/* 左文右图：两栏按黄金比例 1.618 : 1 划分，分割线正好落在整体宽度的 61.8%，
   左栏文案在栏内居中，右栏配图退让 */
.hero-inner {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.618fr) minmax(0, 1fr);
  align-items: center;
  gap: 32px;
  max-width: 1080px;
  margin: 0 auto;
}

.hero-copy {
  justify-self: center;
  max-width: 660px;
  text-align: center;
}

.hero-logo {
  width: 112px;
  height: 112px;
  border-radius: 26px;
  margin: 0 auto 29px;
  box-shadow: var(--shadow-md);
}

.hero-title {
  font-size: clamp(40px, 5.8vw, 64px);
  line-height: 1.15;
  margin: 0 0 18px;
  font-weight: 800;
  letter-spacing: 6px;
  /* 字距靠右侧补偿，避免居中时整体偏左 */
  text-indent: 6px;
}

.hero-title em {
  /* 主标题里的 e 加一层柔和蓝色光晕，呼吸式明暗变化 */
  text-shadow:
    0 0 14px rgba(46, 124, 214, .40),
    0 0 30px rgba(46, 124, 214, .22);
  animation: e-glow 3.6s ease-in-out infinite;
}

@keyframes e-glow {
  0%, 100% {
    text-shadow:
      0 0 12px rgba(46, 124, 214, .30),
      0 0 26px rgba(46, 124, 214, .16);
  }
  50% {
    text-shadow:
      0 0 18px rgba(46, 124, 214, .55),
      0 0 40px rgba(46, 124, 214, .30);
  }
}

@media (prefers-reduced-motion: reduce) {
  .hero-title em { animation: none; }
}

/* 两行标语同一套样式，第二行只在下外边距上不同 */
.hero-slogan,
.hero-subtitle {
  font-size: clamp(20px, 2.6vw, 28px);
  color: var(--blue-700);
  font-weight: 600;
  letter-spacing: 3px;
  text-indent: 3px;
  /* 两行标语属同一视觉单元，行间距最小；下方留白按 φ 递进拉开层级 */
  margin: 0 0 11px;
}

.hero-subtitle {
  margin-bottom: 46px;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 48px;
  flex-wrap: wrap;
}

.hero-actions .btn {
  padding: 16px 52px;
  font-size: 17px;
  letter-spacing: 2px;
}

.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
  /* 配图左右各留透明边，右侧内缩让它向文案靠拢，收紧中间留白 */
  padding-right: 32px;
}

.hero-art {
  width: 100%;
  max-width: 360px;
  height: auto;
  /* 配图作陪衬：降饱和与透明度，避免抢走左侧文案的视觉重心 */
  opacity: .82;
  filter: saturate(.9);
  /* 图片底部为透明留白，负外边距抵消后视觉更贴合文案 */
  margin-bottom: -6%;
  animation: hero-float 6s ease-in-out infinite;
}

@keyframes hero-float {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-10px); }
}

@media (prefers-reduced-motion: reduce) {
  .hero-art { animation: none; }
}

/* ---------- Section shared ---------- */

.section-title {
  text-align: center;
  font-size: clamp(24px, 3.4vw, 30px);
  font-weight: 800;
  margin: 0 0 10px;
}

.section-subtitle {
  text-align: center;
  color: var(--ink-soft);
  font-size: 15px;
  max-width: 680px;
  margin: 0 auto 52px;
}

.section-subtitle--nowrap {
  max-width: 100%;
  white-space: nowrap;
  font-size: clamp(11px, 2.6vw, 15px);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  padding-bottom: 2px;
}

/* ---------- Features ---------- */

.features { padding: 96px 0; }

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
}

.feature-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 30px 24px;
  transition: box-shadow .2s ease, transform .2s ease, border-color .2s ease;
}

.feature-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--blue-200);
  transform: translateY(-3px);
}

.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  border-radius: 14px;
  background: var(--blue-100);
  color: var(--blue-600);
  margin-bottom: 18px;
}
.feature-icon svg { width: 26px; height: 26px; }

.feature-card h3 {
  font-size: 17px;
  margin: 0 0 10px;
  font-weight: 700;
}

.feature-card p {
  font-size: 14px;
  color: var(--ink-soft);
  margin: 0;
  line-height: 1.75;
}

/* ---------- Download ---------- */

.download {
  padding: 96px 0 110px;
  background: var(--blue-50);
}

.download-panels {
  display: flex;
  gap: 24px;
  align-items: stretch;
  flex-wrap: wrap;
}

.panel {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: 40px 36px;
  flex: 1 1 380px;
}

.panel h3 {
  font-size: 18px;
  font-weight: 700;
  margin: 0 0 26px;
  text-align: center;
}

/* QR panel */

.panel-qr { display: flex; flex-direction: column; align-items: center; }

.qr-frame {
  position: relative;
  width: 196px;
  height: 196px;
  padding: 14px;
}

.qr-corner {
  position: absolute;
  width: 22px;
  height: 22px;
  border: 3px solid var(--blue-500);
}
.qr-corner-tl { top: 0; left: 0; border-right: none; border-bottom: none; border-radius: 6px 0 0 0; }
.qr-corner-tr { top: 0; right: 0; border-left: none; border-bottom: none; border-radius: 0 6px 0 0; }
.qr-corner-bl { bottom: 0; left: 0; border-right: none; border-top: none; border-radius: 0 0 0 6px; }
.qr-corner-br { bottom: 0; right: 0; border-left: none; border-top: none; border-radius: 0 0 6px 0; }

.qr-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  border: 1.5px dashed var(--blue-300);
  border-radius: var(--radius-sm);
  background: var(--blue-50);
  overflow: hidden;
}

.qr-placeholder img { width: 100%; height: 100%; object-fit: contain; }

.qr-tip {
  margin: 22px 0 0;
  font-size: 14px;
  color: var(--ink-soft);
  text-align: center;
}

/* App panel */

.panel-app-desc {
  text-align: center;
  font-size: 13.5px;
  color: var(--ink-faint);
  margin: -14px 0 26px;
}

.app-buttons {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.app-btn {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 20px;
  border-radius: var(--radius-md);
  background: var(--blue-900);
  color: var(--white);
  transition: background-color .15s ease, transform .15s ease;
}
.app-btn:hover { background: #0D2E56; transform: translateY(-1px); }

.app-btn.is-disabled {
  opacity: .55;
  cursor: not-allowed;
  pointer-events: none;
}

.app-btn svg { width: 26px; height: 26px; flex: none; }

.app-btn span {
  display: flex;
  flex-direction: column;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.3;
}

.app-btn small {
  font-size: 11.5px;
  font-weight: 400;
  color: rgba(255, 255, 255, 0.68);
}

/* ---------- Footer ---------- */

/* 固定在视口底部。body 的 padding-bottom 由 js/script.js 按页脚实际高度动态补偿，
   下方 CSS 里的值只是脚本执行前的兜底，取值贴近实际高度以减小首帧遮挡。 */
.site-footer {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 90;
  padding: 14px 0;
  /* 带一点蓝调的半透明底，比纯白更贴合整体色板；毛玻璃让固定条压在内容上时不显厚重 */
  background: rgba(245, 250, 255, 0.94);
  backdrop-filter: saturate(180%) blur(12px);
  border-top: 1px solid var(--border);
  box-shadow: 0 -1px 16px rgba(20, 60, 110, 0.05);
}

body { padding-bottom: 88px; }

/* ----- 友情链接抽屉 ----- */

/* 外层只负责动画：max-height 由 JS 按内容实测写入（CSS 无法过渡到 auto）。
   间距放在外层而不是内层，是为了让 scrollHeight 只等于内容高度，展开时不会算少而裁掉边框。 */
.footer-links-panel {
  max-height: 0;
  margin-bottom: 0;
  overflow: hidden;
  transition:
    max-height 0.3s cubic-bezier(0.22, 1, 0.36, 1),
    margin-bottom 0.3s cubic-bezier(0.22, 1, 0.36, 1);
}

.footer-links-panel.is-open { margin-bottom: 11px; }

.footer-links {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  /* 列间距同时作用于分隔符两侧，相邻链接的实际间隔为 18+1+18≈37px */
  gap: 8px 18px;
  padding-bottom: 11px;
  border-bottom: 1px solid var(--border);
  font-size: 12.5px;
  /* 内容比外层容器慢半拍淡入并轻微上移，抽屉才有"推上来"的观感 */
  opacity: 0;
  transform: translateY(6px);
  transition:
    opacity 0.25s ease,
    transform 0.25s ease;
}

.footer-links-panel.is-open .footer-links {
  opacity: 1;
  transform: translateY(0);
}

/* 用 inline-flex：img 是全局 display:block，不这样处理图标会跑到文字上方另起一行。
   间距由 gap 精确控制，不依赖标签间的空白字符。
   做成共享类而非 .footer-links a，是为了让「暂无链接」的条目（span）复用同一套排版。 */
.footer-links-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--ink-soft);
  transition: color 0.2s ease;
}

/* 只有真正可点的 a 才有 hover 反馈，避免给不可点的条目制造错误的可点暗示 */
a.footer-links-item:hover { color: var(--blue-600); }

/* 四个标志的宽高比从 1.00 到 3.32 不等（民航局是横向的翼形徽标）。
   按「高度对齐 + 限制最大宽度」处理：高度一致保证视觉体量统一，
   宽度封顶避免最宽的那个喧宾夺主。切勿用固定方框，否则横向徽标会被压成一条细线。
   ⚠️ 这条规则不可删：缺了它图片会按原始像素（最大 131px）渲染。 */
.footer-links-logo {
  flex-shrink: 0;
  width: auto;
  height: 16px;
  max-width: 48px;
  object-fit: contain;
}

/* 抽屉开关 */
.footer-links-toggle {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 0;
  font: inherit;
  font-weight: 600;
  color: var(--ink-soft);
  background: none;
  border: 0;
  cursor: pointer;
  transition: color 0.2s ease;
}

.footer-links-toggle:hover,
.footer-links-toggle:focus-visible { color: var(--blue-600); }

.footer-links-toggle__caret {
  width: 11px;
  height: 11px;
  transition: transform 0.3s ease;
}

/* 收起时箭头朝上，提示"向上展开"；展开后翻转朝下表示可收起 */
.footer-links-toggle[aria-expanded="true"] .footer-links-toggle__caret {
  transform: rotate(180deg);
}

/* ----- 品牌 + 法务信息 ----- */

/* 整行居中，与上方友链共用同一条中轴，构图对称 */
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 6px 14px;
  font-size: 12.5px;
  color: var(--ink-faint);
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--ink);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.footer-mark { width: 22px; height: 22px; border-radius: 6px; }

.footer-beian {
  color: inherit;
  transition: color 0.2s ease;
}
.footer-beian:hover { color: var(--blue-600); }

.footer-divider { color: var(--border); }

/* ---------------------------------------------------
   Responsive
   --------------------------------------------------- */

@media (max-width: 1024px) {
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .hero-inner { gap: 24px; }
  .hero-art { max-width: 300px; }
}

/* 窄屏改为上下堆叠：文案居中，主视觉置于其下 */
@media (max-width: 880px) {
  .hero { padding: 72px 0 68px; }
  .hero-inner {
    grid-template-columns: 1fr;
    justify-items: center;
    text-align: center;
    gap: 8px;
  }
  .hero-copy { max-width: 560px; }
  .hero-visual { padding-right: 0; }
  .hero-logo { margin-left: auto; margin-right: auto; }
  .hero-actions { justify-content: center; }
  .hero-art { max-width: 300px; }
}

@media (max-width: 720px) {
  .site-nav { display: none; }
  .hero { padding: 60px 0 56px; }
  .hero-logo { width: 88px; height: 88px; margin-bottom: 20px; }
  .hero-subtitle { margin-bottom: 28px; }
  .hero-actions { gap: 28px; }
  .hero-art { max-width: 240px; }
  .features, .download { padding: 72px 0; }
  .feature-grid { grid-template-columns: 1fr; }
  .panel { padding: 32px 24px; }
  .download-panels { gap: 20px; }
  /* 窄屏页脚会换行，分隔符可能落在行首变成孤立的一竖，直接隐藏改由间距区隔 */
  .site-footer { padding: 12px 0; }
  .footer-links { gap: 8px 16px; padding-bottom: 9px; margin-bottom: 9px; }
  .footer-inner { gap: 4px 12px; }
  .footer-divider { display: none; }
}

@media (max-width: 420px) {
  .container { padding: 0 18px; }
  .hero-actions { gap: 16px; }
  .hero-actions .btn { padding: 13px 26px; font-size: 15px; letter-spacing: 1px; }
}