/* ==========================================================================
   U 蓝中文站 · 共享样式 /assets/site.css
   框架式导航（左轨道 + 顶细框带）+ 蓝图网格 + 宝石色分区
   ========================================================================== */

/* ---------- 1. Reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body,h1,h2,h3,h4,h5,h6,p,figure,blockquote,dl,dd{margin:0}
ul,ol{list-style:none;margin:0;padding:0}
img,svg,video{display:block;max-width:100%}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}
a{color:inherit;text-decoration:none}
table{border-collapse:collapse;width:100%}
main{display:block}
:focus-visible{outline:2px solid var(--electric);outline-offset:3px;border-radius:6px}

/* ---------- 2. Tokens ---------- */
:root{
  --deep:#0A1F44;
  --deep-ink:#061530;
  --mist:#F5F7FB;
  --indigo:#1B2A6B;
  --violet:#4B3B8F;
  --electric:#0066FF;
  --cyan:#4DD0E1;
  --teal:#0E5C63;
  --wine:#7A2E3C;
  --orange:#FF6B35;
  --line:#8892A6;

  --ink:#0A1F44;
  --ink-2:rgba(10,31,68,.72);
  --ink-3:rgba(10,31,68,.52);
  --hair:rgba(10,31,68,.12);
  --hair-dark:rgba(136,146,166,.26);

  --rail-w:168px;
  --topbar-h:56px;

  --r-xl:36px;
  --r-lg:28px;
  --r-md:18px;
  --r-pill:999px;

  --sp:clamp(56px,8vw,112px);
  --shadow:0 30px 60px -34px rgba(6,21,48,.6);
  --ease:cubic-bezier(.22,.9,.28,1);

  --font-display:"Noto Serif SC","Source Han Serif SC","Songti SC",Georgia,"Times New Roman",serif;
  --font-body:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}

/* ---------- 3. Base ---------- */
body{
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  color:var(--ink);
  background-color:var(--mist);
  background-image:
    linear-gradient(rgba(10,31,68,.04) 1px,transparent 1px),
    linear-gradient(90deg,rgba(10,31,68,.04) 1px,transparent 1px);
  background-size:48px 48px,48px 48px;
  padding-top:var(--topbar-h);
  padding-left:var(--rail-w);
  min-height:100vh;
  -webkit-font-smoothing:antialiased;
}
body.nav-open{overflow:hidden}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:800;line-height:1.28;letter-spacing:.01em}
h1{font-size:clamp(30px,4.4vw,52px)}
h2{font-size:clamp(24px,3.2vw,40px)}
h3{font-size:clamp(18px,2.2vw,24px);font-weight:700}
h4{font-size:17px;font-weight:700}
p{max-width:74ch}
strong{font-weight:600}

/* ---------- 4. Utilities ---------- */
.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}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums;letter-spacing:-.01em}
.eyebrow{display:inline-block;font-family:var(--font-mono);font-size:12px;letter-spacing:.26em;text-transform:uppercase;color:var(--ink-3)}
.lede{font-size:clamp(16px,1.6vw,19px);line-height:1.85;color:var(--ink-2);max-width:62ch}
.divider{height:1px;border:0;background:var(--hair);margin:clamp(28px,4vw,48px) 0}
.wrap{width:100%;max-width:1180px;margin:0 auto;padding:0 28px}
.section{padding:var(--sp) 0}
.section--tight{padding:clamp(36px,5vw,64px) 0}
.page-head{padding:clamp(40px,6vw,84px) 0 clamp(24px,3vw,40px)}

/* ---------- 5. Skip link ---------- */
.skip-link{
  position:fixed;top:10px;left:10px;z-index:300;
  transform:translateY(-200%);
  background:#fff;color:var(--deep);
  padding:11px 18px;border-radius:var(--r-pill);
  border:1px solid var(--electric);
  font:600 14px/1 var(--font-body);
  box-shadow:var(--shadow);
  transition:transform .2s var(--ease);
}
.skip-link:focus{transform:none}

/* ---------- 6. Header / rail ---------- */
.site-header{position:relative;z-index:80}

.rail{
  position:fixed;top:0;left:0;bottom:0;width:var(--rail-w);
  z-index:90;
  display:flex;flex-direction:column;
  padding:22px 0 24px;
  background:linear-gradient(180deg,#0A1F44 0%,#061530 64%,#0B2350 100%);
  border-right:1px solid var(--hair-dark);
  overflow:hidden;
}
.rail::before{
  content:"";position:absolute;inset:0;pointer-events:none;opacity:.55;
  background-image:repeating-linear-gradient(180deg,rgba(136,146,166,.12) 0 1px,transparent 1px 28px);
}
.rail > *{position:relative;z-index:1}

.rail__brand{
  display:grid;grid-template-columns:40px minmax(0,1fr);grid-template-rows:auto auto;
  gap:3px 10px;align-items:center;
  padding:4px 14px 22px;
}
.rail__mark{
  grid-row:1 / span 2;
  width:40px;height:40px;border-radius:14px;
  display:grid;place-items:center;
  font-family:var(--font-mono);font-weight:700;font-size:18px;color:#fff;
  background:linear-gradient(140deg,var(--electric),var(--cyan));
  box-shadow:0 12px 26px -14px rgba(77,208,225,.95);
}
.rail__brandname{font-family:var(--font-display);font-size:15px;font-weight:800;color:#fff;line-height:1.2}
.rail__brandtag{font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;color:var(--cyan);line-height:1.2}

.rail__nav{
  flex:1;min-height:0;overflow-y:auto;
  display:flex;flex-direction:column;gap:16px;
  padding:0 14px;
}
.rail__head,.rail__grouptitle,.rail__note{display:none}

.rail__list{border-left:1px solid rgba(136,146,166,.3);padding-left:0}
.rail__link{
  position:relative;
  display:grid;grid-template-columns:18px minmax(0,1fr);gap:10px;align-items:center;
  padding:9px 8px 9px 18px;
  color:rgba(226,234,247,.74);
  transition:color .18s var(--ease),background .18s var(--ease);
}
.rail__link::before{
  content:"";position:absolute;left:-4.5px;top:50%;width:8px;height:8px;margin-top:-4px;
  border-radius:50%;background:#2C3A63;
  transition:background .18s var(--ease),box-shadow .18s var(--ease);
}
.rail__num{font-family:var(--font-mono);font-size:10.5px;letter-spacing:.04em;color:rgba(136,146,166,.85)}
.rail__label{font-size:13.5px;line-height:1.35;white-space:nowrap}
.rail__link:hover{color:#fff;background:rgba(255,255,255,.05)}
.rail__link:hover::before{background:var(--cyan)}
.rail__link[aria-current="page"]{color:#fff;background:rgba(77,208,225,.1)}
.rail__link[aria-current="page"] .rail__num{color:var(--cyan)}
.rail__link[aria-current="page"]::before{
  background:var(--cyan);
  box-shadow:0 0 0 4px rgba(77,208,225,.18);
}

.rail__meta{
  margin-top:auto;display:grid;gap:12px;
  padding:20px 14px 0;
  border-top:1px solid rgba(136,146,166,.22);
}
.rail__cta{
  display:inline-flex;align-items:center;justify-content:center;
  padding:10px 12px;border-radius:var(--r-pill);
  border:1px solid rgba(255,107,53,.55);
  color:#FFD9C9;font-size:13px;font-weight:500;
  transition:background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.rail__cta:hover{background:var(--orange);border-color:var(--orange);color:#fff}

.rail__close{display:none}

/* ---------- 7. Topbar ---------- */
.topbar{
  position:fixed;top:0;left:var(--rail-w);right:0;height:var(--topbar-h);
  z-index:70;display:flex;align-items:center;
  background:rgba(10,31,68,.94);
  -webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);
  border-bottom:1px solid var(--hair-dark);
}
.topbar__inner{
  width:100%;max-width:1240px;margin:0 auto;padding:0 28px;
  display:flex;align-items:center;gap:14px;
}
.topbar__lang{font-size:13px;letter-spacing:.16em;color:#DCE4F2}
.topbar__sep{color:rgba(136,146,166,.7);font-family:var(--font-mono)}
.topbar__note{font-size:12.5px;letter-spacing:.06em;color:rgba(220,228,242,.62)}
.topbar__cta{margin-left:auto}

/* ---------- 8. Buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:11px 20px;border-radius:var(--r-pill);
  border:1px solid transparent;
  font-family:var(--font-body);font-size:14px;font-weight:500;line-height:1;
  letter-spacing:.02em;text-align:center;
  transition:transform .18s var(--ease),background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.btn:hover{transform:translateY(-1px)}
.btn--accent{background:var(--orange);color:#fff;box-shadow:0 14px 30px -16px rgba(255,107,53,.95)}
.btn--accent:hover{background:#FF7E4E}
.btn--primary{background:var(--electric);color:#fff;box-shadow:0 14px 30px -18px rgba(0,102,255,.95)}
.btn--primary:hover{background:#1A78FF}
.btn--ghost{border-color:rgba(136,146,166,.5);color:#E6EDF9}
.btn--ghost:hover{border-color:var(--cyan);color:#fff}
.btn--light{background:#fff;color:var(--deep);border-color:var(--hair)}
.btn--light:hover{border-color:var(--electric);color:var(--electric)}

/* ---------- 9. Badges / pills / tags ---------- */
.badge{
  display:inline-flex;align-items:center;gap:6px;
  padding:5px 11px;border-radius:var(--r-pill);
  font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;
  border:1px solid rgba(136,146,166,.4);color:#CFE0F5;
}
.badge--version{background:rgba(77,208,225,.14);border-color:rgba(77,208,225,.42);color:#BFF0F7}
.pill{
  display:inline-flex;align-items:center;gap:8px;
  padding:6px 14px;border-radius:var(--r-pill);
  border:1px solid var(--hair);background:#fff;
  font-size:12px;letter-spacing:.08em;color:var(--ink-2);
}
.tag{
  display:inline-block;padding:4px 12px;border-radius:var(--r-pill);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.06em;
  background:var(--violet);color:#fff;
}
.tag--teal{background:var(--teal)}
.tag--wine{background:var(--wine)}
.tag--cyan{background:var(--cyan);color:#06283A}
.tag--electric{background:var(--electric)}
.tag--orange{background:var(--orange)}

/* ---------- 10. Mobile nav capsule ---------- */
.nav-capsule{display:none}
.nav-capsule__dots{display:inline-grid;grid-template-columns:repeat(3,4px);gap:3px}
.nav-capsule__dots i{display:block;width:4px;height:4px;border-radius:50%;background:var(--cyan)}

/* ---------- 11. Layout helpers ---------- */
.grid{display:grid;gap:clamp(18px,2.6vw,32px)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.split{display:grid;grid-template-columns:minmax(0,.92fr) minmax(0,1.35fr);gap:clamp(24px,4vw,64px);align-items:start}
.split--reverse{grid-template-columns:minmax(0,1.35fr) minmax(0,.92fr)}

/* ---------- 12. Chapter ---------- */
.chapter{margin:0 0 clamp(26px,3.6vw,44px)}
.chapter__index{
  display:block;font-family:var(--font-mono);font-weight:700;
  font-size:clamp(44px,6.4vw,88px);line-height:.86;letter-spacing:-.05em;
  color:var(--violet);
}
.chapter__title{margin-top:12px;font-size:clamp(24px,3.1vw,40px);color:var(--deep)}
.chapter__lede{margin-top:12px;font-size:16px;color:var(--ink-2);max-width:60ch}
.chapter--tight .chapter__index{font-size:clamp(32px,4vw,52px)}

/* ---------- 13. Jewel bands & cards ---------- */
.band{border-radius:var(--r-xl);padding:clamp(28px,4vw,56px);color:#fff;position:relative;overflow:hidden}
.band h1,.band h2,.band h3,.band p{color:#fff}
.band--indigo{background:linear-gradient(140deg,#1B2A6B,#0A1F44)}
.band--violet{background:linear-gradient(140deg,#4B3B8F,#22184A)}
.band--teal{background:linear-gradient(140deg,#0E5C63,#062F35)}
.band--wine{background:linear-gradient(140deg,#7A2E3C,#3A141C)}

.card{
  background:#fff;border:1px solid var(--hair);border-radius:var(--r-lg);
  padding:clamp(20px,2.6vw,32px);box-shadow:var(--shadow);
}
.card--dark{
  background:linear-gradient(150deg,#0A1F44,#061530);
  border-color:var(--hair-dark);color:#E6EDF9;
}
.card--dark h2,.card--dark h3{color:#fff}

.status{
  display:grid;gap:1px;background:var(--hair);
  border:1px solid var(--hair);border-radius:var(--r-md);overflow:hidden;
}
.status__row{
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:14px 18px;background:#fff;font-size:14px;
}
.status__label{display:inline-flex;align-items:center;color:var(--ink-2)}
.status__value{font-family:var(--font-mono);font-weight:600;color:var(--deep)}
.status__dot{
  display:inline-block;width:8px;height:8px;border-radius:50%;margin-right:9px;
  background:var(--cyan);box-shadow:0 0 0 4px rgba(77,208,225,.18);
}
.status__dot--orange{background:var(--orange);box-shadow:0 0 0 4px rgba(255,107,53,.18)}
.status__dot--wine{background:var(--wine);box-shadow:0 0 0 4px rgba(122,46,60,.16)}

/* ---------- 14. Figure / media ---------- */
.figure{margin:0;display:grid;gap:12px}
.figure__media{
  position:relative;overflow:hidden;aspect-ratio:16 / 9;
  border-radius:var(--r-lg);border:1px solid var(--hair-dark);
  background:linear-gradient(150deg,#0A1F44,#1B2A6B 55%,#4B3B8F);
}
.figure__media::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:
    linear-gradient(rgba(255,255,255,.06) 1px,transparent 1px),
    linear-gradient(90deg,rgba(255,255,255,.06) 1px,transparent 1px);
  background-size:36px 36px,36px 36px;
}
.figure__media img{width:100%;height:100%;object-fit:cover}
.figure--4x3 .figure__media{aspect-ratio:4 / 3}
.figure--21x9 .figure__media{aspect-ratio:21 / 9}
.figure--square .figure__media{aspect-ratio:1 / 1}
.figure--teal .figure__media{background:linear-gradient(150deg,#0E5C63,#062F35)}
.figure--wine .figure__media{background:linear-gradient(150deg,#7A2E3C,#3A141C)}
.figure--indigo .figure__media{background:linear-gradient(150deg,#1B2A6B,#0A1F44)}
.figure__cap{font-family:var(--font-mono);font-size:12.5px;letter-spacing:.04em;color:var(--ink-3)}

/* ---------- 15. Tabs ---------- */
.tabs{display:grid;gap:22px}
.tabs__list{
  display:inline-flex;flex-wrap:wrap;gap:4px;width:max-content;max-width:100%;
  padding:5px;border-radius:var(--r-pill);
  background:rgba(10,31,68,.06);border:1px solid var(--hair);
}
.tabs__tab{
  padding:9px 18px;border-radius:var(--r-pill);
  font-size:14px;font-weight:500;color:var(--ink-2);
  transition:background .18s var(--ease),color .18s var(--ease);
}
.tabs__tab:hover{color:var(--deep)}
.tabs__tab[aria-selected="true"]{
  background:var(--electric);color:#fff;
  box-shadow:0 12px 24px -16px rgba(0,102,255,.95);
}
.tabs__panel{display:grid;gap:16px}
.tabs__panel[hidden]{display:none}

/* ---------- 16. Accordion ---------- */
.accordion{border-top:1px solid var(--hair)}
.accordion__item{border-bottom:1px solid var(--hair)}
.accordion__item summary{
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:20px 4px;cursor:pointer;list-style:none;
  font-family:var(--font-display);font-size:17px;font-weight:700;color:var(--deep);
}
.accordion__item summary::-webkit-details-marker{display:none}
.accordion__item summary::after{
  content:"＋";font-family:var(--font-mono);font-size:17px;color:var(--electric);
}
.accordion__item[open] summary::after{content:"－"}
.accordion__body{padding:0 4px 22px;color:var(--ink-2);max-width:74ch}

/* ---------- 17. Breadcrumbs & prose ---------- */
.breadcrumbs{margin-bottom:22px;font-size:13px;color:var(--ink-3)}
.breadcrumbs ol{display:flex;flex-wrap:wrap;align-items:center;gap:8px}
.breadcrumbs li+li::before{
  content:"/";margin-right:8px;font-family:var(--font-mono);color:rgba(136,146,166,.8);
}
.breadcrumbs a{color:var(--ink-2);border-bottom:1px solid var(--hair);padding-bottom:1px}
.breadcrumbs a:hover{color:var(--electric);border-color:var(--electric)}
.breadcrumbs [aria-current="page"]{color:var(--deep);font-weight:500}

.prose{max-width:70ch;color:var(--ink-2);font-size:16px}
.prose > * + *{margin-top:1.1em}
.prose h2{font-size:clamp(22px,2.4vw,28px);color:var(--deep);margin-top:2em}
.prose h3{font-size:19px;color:var(--deep);margin-top:1.6em}
.prose ul,.prose ol{padding-left:1.35em;list-style:disc}
.prose ol{list-style:decimal}
.prose li + li{margin-top:.4em}
.prose a{color:var(--electric);border-bottom:1px solid rgba(0,102,255,.35)}
.prose a:hover{border-color:var(--electric)}
.prose blockquote{
  border-left:3px solid var(--violet);padding:6px 0 6px 20px;color:var(--ink-2);
}
.prose code{font-family:var(--font-mono);font-size:.9em;background:rgba(10,31,68,.07);padding:2px 6px;border-radius:6px}

/* ---------- 18. Progress & reveal ---------- */
.scroll-progress{
  position:fixed;top:var(--topbar-h);left:var(--rail-w);right:0;height:2px;
  z-index:74;background:rgba(10,31,68,.08);pointer-events:none;
}
.scroll-progress__bar{
  height:100%;width:100%;transform:scaleX(0);transform-origin:0 50%;
  background:linear-gradient(90deg,var(--cyan),var(--electric) 55%,var(--violet));
}
html.js-reveal [data-reveal]{opacity:0;transform:translateY(20px)}
[data-reveal]{
  transition:opacity .55s var(--ease),transform .55s var(--ease);
}
[data-reveal].is-visible{opacity:1;transform:none}

.to-top{
  position:fixed;right:22px;bottom:22px;z-index:100;
  width:46px;height:46px;border-radius:50%;
  display:grid;place-items:center;
  background:#fff;color:var(--deep);border:1px solid var(--hair);
  box-shadow:var(--shadow);font-family:var(--font-mono);font-size:16px;
  opacity:0;visibility:hidden;
  transition:opacity .2s var(--ease),visibility .2s var(--ease),transform .2s var(--ease);
}
.to-top[data-visible]{opacity:1;visibility:visible}
.to-top:hover{transform:translateY(-2px);border-color:var(--electric);color:var(--electric)}

/* ---------- 19. Footer ---------- */
.site-footer{
  position:relative;margin-top:var(--sp);
  background:linear-gradient(180deg,#0A1F44 0%,#061530 80%);
  color:#DCE4F2;
  padding:0 0 40px;
}
.footer__rule{
  height:14px;border-top:1px solid var(--hair-dark);
  background-image:repeating-linear-gradient(90deg,rgba(136,146,166,.55) 0 1px,transparent 1px 28px);
}
.footer__inner{max-width:1180px;margin:0 auto;padding:clamp(40px,5vw,72px) 28px 0}
.footer__top{
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;
  gap:16px;padding-bottom:28px;border-bottom:1px solid var(--hair-dark);
}
.footer__brand{display:inline-flex;align-items:center;gap:12px}
.footer__mark{
  display:grid;place-items:center;width:38px;height:38px;border-radius:13px;
  background:linear-gradient(140deg,var(--electric),var(--cyan));
  color:#fff;font-family:var(--font-mono);font-weight:700;font-size:16px;
}
.footer__brandtext{font-family:var(--font-display);font-size:18px;font-weight:800;color:#fff}
.footer__coords{font-size:12px;letter-spacing:.2em;color:rgba(220,228,242,.5)}

.footer__grid{
  display:grid;grid-template-columns:1.6fr 1fr 1fr;
  gap:clamp(24px,4vw,56px);
  padding:36px 0 32px;
}
.footer__coltitle{font-size:15px;font-weight:700;color:#fff;letter-spacing:.1em}
.footer__coltitle::after{
  content:"";display:block;width:28px;height:2px;margin-top:10px;
  border-radius:2px;background:var(--cyan);
}
.footer__list{display:grid;gap:10px;margin-top:18px}
.footer__item{
  display:flex;flex-wrap:wrap;align-items:baseline;gap:4px 10px;
  font-size:14px;line-height:1.6;
}
.footer__key{min-width:72px;color:rgba(220,228,242,.6);letter-spacing:.06em;font-size:13px}
.footer__val{color:#EAF0FA;word-break:break-all}
.footer__link{
  display:inline-block;font-size:14px;color:#DCE4F2;
  padding:1px 0;border-bottom:1px solid transparent;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.footer__link:hover{color:#fff;border-color:var(--cyan)}
.footer__signoff{margin-top:20px;font-size:13px;line-height:1.9;color:rgba(220,228,242,.62);max-width:32ch}
.footer__legal{
  display:flex;flex-wrap:wrap;gap:8px 24px;justify-content:space-between;
  padding-top:22px;border-top:1px solid var(--hair-dark);
  font-size:13px;color:rgba(220,228,242,.6);
}
.copy-btn{
  padding:3px 10px;border-radius:var(--r-pill);
  border:1px solid rgba(136,146,166,.45);
  font-size:11px;line-height:1.7;letter-spacing:.1em;color:#BFD4F0;
  transition:border-color .18s var(--ease),color .18s var(--ease),background .18s var(--ease);
}
.copy-btn:hover{border-color:var(--cyan);color:#fff}
.copy-btn[data-copy-state="done"]{background:var(--cyan);border-color:var(--cyan);color:#06283A}

/* ---------- 20. Responsive ---------- */
@media (max-width:900px){
  .grid--2,.grid--3,.split,.split--reverse{grid-template-columns:minmax(0,1fr)}
  .footer__grid{grid-template-columns:minmax(0,1fr);gap:34px}
  .footer__signoff{max-width:none}
}

@media (max-width:1023px){
  :root{--rail-w:0px}
  body{padding-left:0;padding-bottom:104px}

  .rail{position:static;width:auto;height:0;padding:0;border:0;background:none;overflow:visible}
  .rail::before{display:none}

  .rail__brand{
    position:fixed;top:0;left:0;z-index:95;
    grid-template-columns:34px auto;gap:2px 9px;
    height:var(--topbar-h);padding:0 12px;align-content:center;
  }
  .rail__mark{width:34px;height:34px;border-radius:12px;font-size:15px}
  .rail__brandname{font-size:14px}
  .rail__brandtag{font-size:10px;letter-spacing:.1em}

  .topbar__inner{padding:0 14px 0 136px;justify-content:flex-end;gap:10px}
  .topbar__lang,.topbar__sep,.topbar__note,.topbar__version{display:none}

  .rail__nav{
    position:fixed;inset:0;z-index:120;
    display:flex;flex-direction:column;gap:22px;
    padding:22px 22px 40px;overflow-y:auto;
    background:linear-gradient(160deg,#0A1F44 0%,#132A5C 48%,#4B3B8F 122%);
    opacity:0;visibility:hidden;pointer-events:none;transform:translateY(10px);
    transition:opacity .24s var(--ease),transform .24s var(--ease),visibility .24s var(--ease);
  }
  .rail__nav[data-open]{opacity:1;visibility:visible;pointer-events:auto;transform:none}

  .rail__head{display:flex;align-items:center;justify-content:space-between;gap:12px}
  .rail__eyebrow{
    display:block;font-family:var(--font-mono);font-size:11px;
    letter-spacing:.26em;color:var(--cyan);margin:0;
  }
  .rail__close{
    display:grid;place-items:center;width:42px;height:42px;border-radius:50%;
    border:1px solid rgba(136,146,166,.45);color:#fff;font-size:20px;line-height:1;
  }
  .rail__close:hover{border-color:var(--cyan);color:var(--cyan)}

  .rail__group{display:grid;gap:10px}
  .rail__grouptitle{
    display:block;margin:0;font-size:12px;letter-spacing:.22em;
    color:rgba(220,228,242,.55);font-family:var(--font-mono);
  }
  .rail__list{border-left:1px solid rgba(136,146,166,.35)}
  .rail__link{grid-template-columns:34px minmax(0,1fr);gap:12px;padding:13px 10px 13px 20px}
  .rail__num{font-size:12px;color:var(--cyan)}
  .rail__label{
    font-family:var(--font-display);font-weight:700;
    font-size:clamp(19px,5.6vw,25px);white-space:normal;letter-spacing:.02em;
  }
  .rail__link[aria-current="page"]{background:rgba(77,208,225,.12)}

  .rail__note{
    display:block;margin:auto 0 0;font-size:12.5px;
    letter-spacing:.14em;color:rgba(220,228,242,.6);font-family:var(--font-mono);
  }
  .rail__meta{display:none}

  .nav-capsule{
    display:inline-flex;position:fixed;left:50%;bottom:20px;transform:translateX(-50%);
    z-index:110;align-items:center;gap:10px;
    padding:13px 24px;border-radius:var(--r-pill);
    border:1px solid rgba(77,208,225,.5);
    background:rgba(8,24,54,.95);color:#fff;
    font-size:14px;font-weight:500;letter-spacing:.06em;
    box-shadow:0 20px 44px -18px rgba(6,21,48,.95);
    -webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);
  }
  .nav-capsule[aria-expanded="true"]{background:var(--electric);border-color:var(--electric)}

  .scroll-progress{left:0}
  .to-top{right:16px;bottom:96px}
}

/* ---------- 21. Focus on dark surfaces ---------- */
.rail :focus-visible,
.topbar :focus-visible,
.site-footer :focus-visible{outline-color:var(--cyan)}

/* ---------- 22. Reduced motion ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  html.js-reveal [data-reveal]{opacity:1;transform:none}
  .btn:hover,.to-top:hover{transform:none}
}