/* ================================================================
   nav.css —— 全站统一导航 + 页脚（9 页共用，由 nav.js 渲染）
   浅色玻璃顶栏；≤640px 收敛为 logo + 三个高频图标 + 汉堡；
   data-immersive（/cosmos、/planet）下改为右上角悬浮导航按钮。
   ================================================================ */
:root{
  --nav-h:64px;
}

/* ---------------- 顶栏 ---------------- */
.site-nav{
  position:sticky;top:0;z-index:60;
  padding:calc(10px + env(safe-area-inset-top,0px)) 16px 10px;
  backdrop-filter:blur(14px) saturate(1.4);
  -webkit-backdrop-filter:blur(14px) saturate(1.4);
  background:linear-gradient(180deg,rgba(253,248,251,.92),rgba(253,248,251,.72));
  border-bottom:1px solid rgba(244,228,240,.9);
}
.nav-inner{
  max-width:1100px;margin:0 auto;height:44px;
  display:flex;align-items:center;gap:18px;
}
.nav-logo{
  display:inline-flex;align-items:center;gap:9px;text-decoration:none;color:var(--fg,#3D3040);
  font-weight:800;font-size:15.5px;letter-spacing:.02em;white-space:nowrap;
}
.nav-logo .dot{
  width:11px;height:11px;border-radius:50%;
  background:linear-gradient(135deg,var(--a,#EC4899),var(--b,#8B5CF6));
  box-shadow:0 0 12px rgba(236,72,153,.55);
}
.nav-links{display:flex;align-items:center;gap:2px;margin-left:auto}
.nav-links a{
  text-decoration:none;color:var(--fg2,#6E5F77);font-weight:700;font-size:13px;
  padding:7px 10px;border-radius:11px;transition:color .18s,background .18s;white-space:nowrap;
}
.nav-links a:hover{color:var(--fg,#3D3040);background:rgba(139,92,246,.07)}
.nav-links a[aria-current="page"]{
  color:#fff;background:linear-gradient(120deg,var(--a,#EC4899),var(--b,#8B5CF6));
  box-shadow:0 6px 16px -8px rgba(139,92,246,.6);
}
.nav-quick{display:none;gap:4px;margin-left:auto}

/* 「更多」下拉 */
.nav-more{position:relative}
.nav-more-btn{
  display:inline-flex;align-items:center;gap:5px;
  font:inherit;font-weight:700;font-size:13px;color:var(--fg2,#6E5F77);
  background:none;border:none;cursor:pointer;
  padding:7px 10px;border-radius:11px;
  transition:color .18s,background .18s;white-space:nowrap;
}
.nav-more-btn:hover,.nav-more-btn[aria-expanded="true"]{
  color:var(--fg,#3D3040);background:rgba(139,92,246,.07);
}
.nav-more-btn svg{
  width:13px;height:13px;fill:none;stroke:currentColor;stroke-width:2.4;
  stroke-linecap:round;stroke-linejoin:round;
  transition:transform .2s cubic-bezier(.22,1,.36,1);
}
.nav-more-btn[aria-expanded="true"] svg{transform:rotate(180deg)}
.nav-more-menu{
  position:absolute;top:calc(100% + 10px);right:0;
  min-width:180px;padding:7px;
  display:grid;gap:2px;
  background:rgba(255,255,255,.97);
  -webkit-backdrop-filter:blur(18px) saturate(1.4);
  backdrop-filter:blur(18px) saturate(1.4);
  border:1px solid rgba(244,228,240,.95);
  border-radius:16px;
  box-shadow:0 18px 48px -18px rgba(61,48,64,.32),0 2px 8px -4px rgba(139,92,246,.2);
  z-index:90;
  animation:moreIn .18s cubic-bezier(.22,1,.36,1);
}
.nav-more-menu[hidden]{display:none}
@keyframes moreIn{from{opacity:0;transform:translateY(-6px)}to{opacity:1;transform:none}}
.nav-more-menu a{
  display:block;text-decoration:none;
  color:var(--fg2,#6E5F77);font-weight:700;font-size:13.5px;
  padding:9px 13px;border-radius:10px;
  transition:color .15s,background .15s;
}
.nav-more-menu a:hover{color:var(--fg,#3D3040);background:rgba(139,92,246,.08)}
.nav-more-menu a[aria-current="page"]{
  color:#fff;background:linear-gradient(120deg,var(--a,#EC4899),var(--b,#8B5CF6));
}
@media (prefers-reduced-motion:reduce){.nav-more-menu{animation:none}}
.nav-quick a{
  display:grid;place-items:center;width:38px;height:38px;border-radius:12px;
  text-decoration:none;font-size:17px;line-height:1;
  background:rgba(255,255,255,.85);border:1px solid var(--line,#F4E4F0);
  box-shadow:0 2px 8px -4px rgba(139,92,246,.25);
}
.nav-burger{
  display:none;width:38px;height:38px;border:1px solid var(--line,#F4E4F0);border-radius:12px;
  background:rgba(255,255,255,.9);cursor:pointer;position:relative;flex:none;
}
.nav-burger span,.nav-burger span::before,.nav-burger span::after{
  content:"";position:absolute;left:50%;top:50%;width:16px;height:2px;border-radius:2px;
  background:var(--fg,#3D3040);transform:translate(-50%,-50%);transition:transform .22s;
}
.nav-burger span::before{transform:translate(-50%,-6px)}
.nav-burger span::after{transform:translate(-50%,6px)}
.nav-burger[aria-expanded="true"] span{background:transparent}
.nav-burger[aria-expanded="true"] span::before{transform:translate(-50%,-50%) rotate(45deg)}
.nav-burger[aria-expanded="true"] span::after{transform:translate(-50%,-50%) rotate(-45deg)}

/* 展开面板（移动端） */
.nav-panel{
  max-width:1100px;margin:0 auto;overflow:hidden;
  display:grid;grid-template-columns:repeat(3,1fr);gap:8px;
  padding:0 0 6px;transition:max-height .3s var(--ease,cubic-bezier(.22,1,.36,1)),opacity .2s;
}
.nav-panel[hidden]{display:none}
.nav-panel a{
  text-decoration:none;color:var(--fg,#3D3040);font-weight:700;font-size:13.5px;
  padding:12px 10px;border-radius:12px;text-align:center;
  background:rgba(255,255,255,.9);border:1px solid var(--line2,#F9EFF7);
}
.nav-panel a[aria-current="page"]{background:linear-gradient(120deg,rgba(236,72,153,.14),rgba(139,92,246,.14));color:var(--fg,#3D3040)}

/* ---------------- 沉浸页（/cosmos、/planet） ---------------- */
body[data-immersive] .site-nav{
  position:fixed;top:auto;bottom:calc(18px + env(safe-area-inset-bottom,0px));right:16px;
  left:auto;padding:0;border:0;background:none;backdrop-filter:none;-webkit-backdrop-filter:none;
  z-index:80;
}
body[data-immersive] .nav-inner{height:auto;gap:0}
body[data-immersive] .nav-logo,
body[data-immersive] .nav-links,
body[data-immersive] .nav-quick{display:none}
body[data-immersive] .nav-burger{
  display:grid;place-items:center;width:48px;height:48px;border-radius:16px;
  background:rgba(12,14,32,.72);border:1px solid rgba(160,180,255,.28);
  box-shadow:0 10px 30px -12px rgba(0,0,0,.7);
}
body[data-immersive] .nav-burger span,
body[data-immersive] .nav-burger span::before,
body[data-immersive] .nav-burger span::after{background:#dfe6ff}
body[data-immersive] .nav-panel{
  position:fixed;right:16px;bottom:calc(76px + env(safe-area-inset-bottom,0px));
  width:min(88vw,340px);grid-template-columns:repeat(3,1fr);padding:10px;
  border-radius:18px;background:rgba(10,12,28,.92);border:1px solid rgba(160,180,255,.22);
  box-shadow:0 24px 60px -20px rgba(0,0,0,.8);backdrop-filter:blur(16px);
}
body[data-immersive] .nav-panel a{
  background:rgba(255,255,255,.06);border-color:rgba(160,180,255,.16);color:#e8ecff;
}

/* ---------------- 相关推荐（全站自动挂载） ---------------- */
.related-nav{
  max-width:1100px;margin:72px auto 0;
  padding:0 20px;
}
.related-head{margin-bottom:20px}
.related-title{
  margin:0 0 5px;font-size:19px;font-weight:800;
  color:var(--fg,#3D3040);letter-spacing:.01em;
}
.related-sub{
  margin:0;font-size:13px;font-weight:600;
  color:var(--fg2,#8A7B92);opacity:.85;
}
.related-grid{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:12px;
}
.related-card{
  display:flex;align-items:center;gap:12px;
  padding:16px 16px;
  background:rgba(255,255,255,.72);
  -webkit-backdrop-filter:blur(12px);
  backdrop-filter:blur(12px);
  border:1px solid rgba(244,228,240,.95);
  border-radius:16px;
  text-decoration:none;
  transition:transform .22s cubic-bezier(.22,1,.36,1),
             box-shadow .22s cubic-bezier(.22,1,.36,1),
             border-color .22s;
  min-height:74px;
}
.related-card:hover{
  transform:translateY(-2px);
  border-color:rgba(139,92,246,.32);
  box-shadow:0 14px 34px -18px rgba(139,92,246,.55);
}
.related-card:focus-visible{
  outline:2px solid var(--b,#8B5CF6);
  outline-offset:2px;
}
.related-ico{
  width:34px;height:34px;border-radius:10px;flex-shrink:0;
  display:grid;place-items:center;
  background:linear-gradient(135deg,rgba(236,72,153,.13),rgba(139,92,246,.13));
}
.related-ico svg{
  width:17px;height:17px;fill:none;
  stroke:var(--b,#8B5CF6);stroke-width:1.9;
  stroke-linecap:round;stroke-linejoin:round;
}
.related-body{
  flex:1;min-width:0;
  display:flex;flex-direction:column;gap:2px;
}
.related-t{
  font-size:13.5px;font-weight:800;
  color:var(--fg,#3D3040);
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
.related-d{
  font-size:11.5px;font-weight:600;line-height:1.35;
  color:var(--fg2,#8A7B92);opacity:.9;
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;
  overflow:hidden;
}
.related-arrow{
  flex-shrink:0;display:grid;place-items:center;
  opacity:0;transform:translateX(-4px);
  transition:opacity .2s,transform .2s;
}
.related-arrow svg{
  width:15px;height:15px;fill:none;
  stroke:var(--b,#8B5CF6);stroke-width:2;
  stroke-linecap:round;stroke-linejoin:round;
}
.related-card:hover .related-arrow{opacity:1;transform:none}

@media (max-width:900px){
  .related-grid{grid-template-columns:repeat(2,1fr)}
  .related-nav{margin-top:56px}
}
@media (max-width:600px){
  .related-grid{grid-template-columns:1fr;gap:10px}
  .related-nav{margin-top:48px;padding:0 18px}
  .related-title{font-size:17px}
  .related-card{min-height:0;padding:14px}
}
@media (prefers-reduced-motion:reduce){
  .related-card,.related-arrow{transition:none}
  .related-card:hover{transform:none}
}
/* 沉浸页（/cosmos）：浮在星空上方的暗色玻璃卡片 */
body[data-immersive] .related-nav{
  position:relative;z-index:5;
  max-width:900px;margin:0 auto;
  padding:0 20px 120px;
}
body[data-immersive] .related-title{color:#e8ecff}
body[data-immersive] .related-sub{color:rgba(200,210,255,.62)}
body[data-immersive] .related-card{
  background:rgba(16,18,40,.62);
  border-color:rgba(160,180,255,.22);
  -webkit-backdrop-filter:blur(14px);
  backdrop-filter:blur(14px);
}
body[data-immersive] .related-card:hover{
  border-color:rgba(160,180,255,.48);
  box-shadow:0 16px 40px -18px rgba(120,150,255,.6);
}
body[data-immersive] .related-t{color:#eef2ff}
body[data-immersive] .related-d{color:rgba(200,210,255,.66)}
body[data-immersive] .related-ico{
  background:linear-gradient(135deg,rgba(120,150,255,.18),rgba(180,120,255,.18));
}
body[data-immersive] .related-ico svg,
body[data-immersive] .related-arrow svg{stroke:#a5b8ff}

/* 暗色页面（/signal、/scenes）：相关推荐也要跟着变暗，否则白卡扎眼 */
body.signal-page .related-nav,
body.scenes-page .related-nav{position:relative;z-index:2}
body.signal-page .related-title,
body.scenes-page .related-title{color:#e8ecff}
body.signal-page .related-sub,
body.scenes-page .related-sub{color:rgba(200,210,255,.6)}
body.signal-page .related-card,
body.scenes-page .related-card{
  background:rgba(16,18,40,.62);
  border-color:rgba(160,180,255,.22);
}
body.signal-page .related-card:hover,
body.scenes-page .related-card:hover{
  border-color:rgba(160,180,255,.48);
  box-shadow:0 16px 40px -18px rgba(120,150,255,.6);
}
body.signal-page .related-t,
body.scenes-page .related-t{color:#eef2ff}
body.signal-page .related-d,
body.scenes-page .related-d{color:rgba(200,210,255,.66)}
body.signal-page .related-ico,
body.scenes-page .related-ico{
  background:linear-gradient(135deg,rgba(120,150,255,.18),rgba(180,120,255,.18));
}
body.signal-page .related-ico svg,
body.signal-page .related-arrow svg,
body.scenes-page .related-ico svg,
body.scenes-page .related-arrow svg{stroke:#a5b8ff}

/* ---------------- 页脚 ---------------- */
.site-foot{
  max-width:1100px;margin:56px auto 0;padding:28px 20px calc(34px + env(safe-area-inset-bottom,0px));
  border-top:1px solid var(--line,#F4E4F0);
  display:flex;flex-wrap:wrap;gap:14px 22px;align-items:center;justify-content:center;
  text-align:center;color:var(--fg2,#6E5F77);font-size:12.5px;
}
.site-foot nav{display:flex;flex-wrap:wrap;gap:6px 14px;justify-content:center}
.site-foot a{color:var(--fg2,#6E5F77);text-decoration:none;font-weight:700}
.site-foot a:hover{color:var(--a,#EC4899)}
.site-foot .foot-sep{opacity:.4}
body[data-immersive] .site-foot{display:none}

/* 12 个导航项在窄屏放不下，900px 以下收敛为 快捷图标 + 汉堡（面板内是全量 12 项） */
@media (max-width:900px){
  .site-nav{padding-left:12px;padding-right:12px}
  .nav-links{display:none}
  .nav-quick{display:flex}
  .nav-burger{display:block}
  .nav-panel{grid-template-columns:repeat(3,1fr)}
}
@media (max-width:640px){
  .nav-panel{grid-template-columns:repeat(2,1fr)}
}

/* ---- v3 可达性与图标升级：SVG 快捷图标 / 焦点可见 / 44px 触摸区 ---- */
.nav-quick a { color: var(--fg2, #6E5F77); }
.nav-quick a svg { width: 19px; height: 19px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.nav-quick a:hover { color: var(--fg, #3D3040); border-color: rgba(139, 92, 246, .45); }
.nav-quick a[aria-current="page"] {
  color: #fff;
  background: linear-gradient(120deg, var(--a, #EC4899), var(--b, #8B5CF6));
  border-color: transparent;
}
.nav-links a:focus-visible, .nav-quick a:focus-visible, .nav-burger:focus-visible,
.nav-logo:focus-visible, .nav-panel a:focus-visible {
  outline: 2px solid var(--b, #8B5CF6);
  outline-offset: 2px;
}
@media (max-width: 640px) {
  .nav-links a { min-height: 44px; display: inline-flex; align-items: center; }
  .nav-panel a { min-height: 44px; display: flex; align-items: center; justify-content: center; }
  .nav-quick a { width: 44px; height: 44px; }
  .nav-burger { width: 44px; height: 44px; }
}