:root{
  --r-bg:#050607;--r-bg2:#0a0d0f;--r-panel:#0d1113;--r-panel2:#11171a;
  --r-ink:#eee9dd;--r-muted:#9da6a9;--r-line:#30383c;--r-silver:#bbc7cc;
  --r-gold:#c7a75f;--r-gold2:#e2cb8e;--r-cyan:#79d0e6;--r-cyan2:#c4f0fb;
  --r-focus:#9ae9f7;--r-shadow:0 26px 90px rgba(0,0,0,.44)
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;background:var(--r-bg)}
body.rayo-room{margin:0;background:radial-gradient(circle at 50% -15%,rgba(121,208,230,.085),transparent 36rem),linear-gradient(180deg,#050607,#090c0e 52%,#050607);color:var(--r-ink);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.58}
.rayo-room a{color:inherit}.rayo-room button,.rayo-room input{font:inherit}.rayo-room button{cursor:pointer}.rayo-room a:focus-visible,.rayo-room button:focus-visible,.rayo-room input:focus-visible{outline:2px solid var(--r-focus);outline-offset:4px}
.rayo-skip{position:absolute;left:-9999px;top:0}.rayo-skip:focus{left:16px;top:16px;z-index:100;background:#111;padding:10px 14px;border:1px solid var(--r-focus)}
.rayo-sitebar{position:sticky;top:0;z-index:30;background:rgba(5,6,7,.88);backdrop-filter:blur(16px);border-bottom:1px solid rgba(199,167,95,.18)}
.rayo-sitebar-inner{width:min(1240px,calc(100% - 32px));margin:auto;min-height:62px;display:flex;align-items:center;gap:16px}.rayo-brand{display:flex;align-items:center;gap:11px;text-decoration:none}.rayo-hg{width:38px;height:38px;display:grid;place-items:center;border:1px solid rgba(199,167,95,.62);font-family:Georgia,serif;color:var(--r-gold2)}.rayo-brand strong{display:block;font-family:Georgia,serif;font-weight:500;letter-spacing:.035em}.rayo-brand span span{display:block;color:var(--r-muted);font-size:10px;letter-spacing:.16em;text-transform:uppercase}.rayo-nav{margin-left:auto;display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}.rayo-nav a{text-decoration:none;padding:8px 10px;border:1px solid var(--r-line);font-size:10px;letter-spacing:.13em;text-transform:uppercase;color:var(--r-muted)}.rayo-nav a[aria-current="page"]{color:var(--r-gold2);border-color:rgba(199,167,95,.52)}
.rayo-shell{width:min(1180px,calc(100% - 40px));margin:auto}.rayo-hero{min-height:78vh;display:grid;align-items:center;padding:82px 0 68px;border-bottom:1px solid rgba(255,255,255,.06);position:relative;overflow:hidden}.rayo-hero:after{content:"";position:absolute;left:0;right:0;bottom:13%;height:1px;background:linear-gradient(90deg,transparent,var(--r-silver) 20%,var(--r-gold) 50%,var(--r-silver) 80%,transparent);opacity:.5}.rayo-hero-copy{position:relative;z-index:2;max-width:900px}.rayo-eyebrow{font-size:11px;letter-spacing:.18em;text-transform:uppercase;color:var(--r-gold2)}.rayo-room h1,.rayo-room h2,.rayo-room h3{font-family:Georgia,"Times New Roman",serif;font-weight:500;line-height:1.03;margin:0}.rayo-room h1{font-size:clamp(48px,8vw,108px);letter-spacing:-.045em}.rayo-room h2{font-size:clamp(34px,5vw,68px);letter-spacing:-.035em}.rayo-room h3{font-size:clamp(22px,3vw,34px)}.rayo-lead{font-size:clamp(17px,2vw,23px);max-width:780px;color:#d5d8d5}.rayo-hero .rayo-lead{margin:24px 0}.rayo-note{font-size:13px;color:var(--r-muted);max-width:800px}.rayo-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:28px}.rayo-action{display:inline-flex;align-items:center;justify-content:center;min-height:46px;padding:12px 16px;border:1px solid rgba(199,167,95,.52);background:linear-gradient(180deg,#17150f,#0a0a08);color:var(--r-gold2);text-decoration:none;text-transform:uppercase;letter-spacing:.105em;font-size:11px;font-weight:700}.rayo-action.secondary{border-color:rgba(121,208,230,.42);background:#071013;color:var(--r-cyan2)}.rayo-action.ghost{border-color:var(--r-line);background:#090b0d;color:var(--r-muted)}
.rayo-section{padding:84px 0;border-bottom:1px solid rgba(255,255,255,.055)}.rayo-section-head{max-width:860px;margin-bottom:30px}.rayo-section-head .rayo-lead{margin:14px 0 0}.rayo-bay{display:grid;grid-template-columns:minmax(0,1.55fr) minmax(280px,.75fr);gap:24px;align-items:stretch}.rayo-apparatus{position:relative;min-height:420px;padding:26px;background:linear-gradient(135deg,rgba(255,255,255,.024),transparent 42%),linear-gradient(180deg,#0e1214,#080a0b);border:1px solid rgba(187,199,204,.18);box-shadow:var(--r-shadow);overflow:hidden}.rayo-apparatus:before,.rayo-apparatus:after{content:"";position:absolute;top:13px;width:7px;height:7px;border:1px solid #5b656a;border-radius:50%}.rayo-apparatus:before{left:13px}.rayo-apparatus:after{right:13px}.rayo-controls{padding:22px;background:linear-gradient(180deg,#111619,#090b0c);border:1px solid rgba(199,167,95,.2);display:flex;flex-direction:column;gap:16px}.rayo-watch{font-size:10px;letter-spacing:.15em;text-transform:uppercase;color:var(--r-gold2);margin-bottom:5px}.rayo-plate{padding:12px 14px;border-left:2px solid var(--r-gold);background:rgba(199,167,95,.045);color:#ddd7c8}.rayo-plate.cyan{border-left-color:var(--r-cyan);background:rgba(121,208,230,.04)}.rayo-value{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;color:var(--r-cyan2)}.rayo-hidden{display:none!important}.rayo-reveal{animation:rayoReveal .4s ease both}@keyframes rayoReveal{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}
.rayo-prediction{display:grid;gap:9px}.rayo-choice{min-height:44px;padding:10px 12px;border:1px solid var(--r-line);background:#0a0e10;color:var(--r-ink);text-align:left}.rayo-choice[aria-pressed="true"]{border-color:var(--r-gold);background:rgba(199,167,95,.08);color:#fff0c4}.rayo-choice:disabled{opacity:.54;cursor:default}.rayo-equation{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;padding:12px 14px;border-top:1px solid rgba(199,167,95,.3);color:#e3ddcb}.rayo-proof{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;margin-top:18px}.rayo-proof-step{border:1px solid var(--r-line);padding:12px;min-height:100px;background:#0a0e10}.rayo-proof-step span{display:block;font-size:9px;letter-spacing:.13em;color:var(--r-gold2);text-transform:uppercase;margin-bottom:6px}.rayo-proof-step b{font-size:13px;font-weight:600}.rayo-status{display:inline-flex;align-items:center;gap:8px;font-size:10px;letter-spacing:.13em;text-transform:uppercase;color:var(--r-muted)}.rayo-status:before{content:"";width:8px;height:8px;border-radius:50%;background:#4e575b}.rayo-status.done{color:var(--r-cyan2)}.rayo-status.done:before{background:var(--r-cyan);box-shadow:0 0 12px rgba(121,208,230,.5)}
.hotel{display:grid;grid-template-columns:repeat(8,minmax(52px,1fr));gap:8px;margin-top:24px}.room{border:1px solid #343d41;background:#090c0e;min-height:72px;padding:8px;display:flex;flex-direction:column;justify-content:space-between;transition:transform .5s ease,border-color .3s,background .3s}.room small{color:var(--r-muted);font-size:9px;letter-spacing:.1em}.room strong{font-size:12px}.room.shift{transform:translateX(10px);border-color:rgba(121,208,230,.65);background:rgba(121,208,230,.06)}.room.new{border-color:var(--r-gold);background:rgba(199,167,95,.08)}
.diagonal-table{display:grid;grid-template-columns:50px repeat(8,36px);gap:4px;align-items:center;margin-top:22px;width:max-content;max-width:100%;overflow:auto;padding-bottom:8px}.diag-cell{display:grid;place-items:center;min-height:34px;border:1px solid #2e373a;background:#090c0e;font:13px ui-monospace,monospace}.diag-cell.label{border:0;background:transparent;color:var(--r-muted);font-size:10px}.diag-cell.hit{border-color:var(--r-gold);color:var(--r-gold2);background:rgba(199,167,95,.075)}.diag-cell.changed{border-color:var(--r-cyan);color:var(--r-cyan2);background:rgba(121,208,230,.06)}.constructed-number{margin-top:16px;font:clamp(18px,3vw,28px) ui-monospace,monospace;color:var(--r-cyan2);word-break:break-all}
.rayo-progress{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;margin:26px 0 0}.rayo-progress div{border-top:2px solid #343c40;padding-top:9px;color:var(--r-muted);font-size:9px;letter-spacing:.11em;text-transform:uppercase}.rayo-progress div.done{border-color:var(--r-cyan);color:var(--r-cyan2)}
.rayo-study-grid{display:grid;grid-template-columns:240px minmax(0,1fr);gap:28px;align-items:start}.rayo-study-nav{position:sticky;top:82px;border:1px solid var(--r-line);background:#090c0e;padding:12px}.rayo-study-nav a{display:block;text-decoration:none;padding:10px;border-bottom:1px solid rgba(255,255,255,.055);font-size:11px;color:var(--r-muted)}.rayo-study-nav a:hover{color:var(--r-ink)}.rayo-study-card{border:1px solid var(--r-line);background:linear-gradient(180deg,#0d1113,#090b0c);padding:24px;margin-bottom:18px}.rayo-study-card p:last-child{margin-bottom:0}.rayo-tool-drawer{border:1px solid rgba(121,208,230,.25);background:#081012;padding:16px;margin-top:18px}.rayo-tool-drawer summary{cursor:pointer;color:var(--r-cyan2);font-size:11px;letter-spacing:.12em;text-transform:uppercase}.rayo-tool-drawer p{color:#cfd7d8}.rayo-mapping{display:grid;grid-template-columns:1fr 72px 1fr;gap:10px;align-items:center;margin-top:16px}.rayo-token-column{display:grid;gap:8px}.rayo-token{padding:10px;border:1px solid var(--r-line);background:#080b0c;text-align:center;font:12px ui-monospace,monospace}.rayo-map-arrow{text-align:center;color:var(--r-gold2);font-size:24px}.rayo-check{margin-top:16px;padding:14px;border:1px solid rgba(199,167,95,.25);background:rgba(199,167,95,.035)}.rayo-check button{margin-top:8px}.rayo-footer{padding:34px 0 50px;color:var(--r-muted);font-size:12px}.rayo-attribution{border-top:1px solid var(--r-line);padding-top:18px;margin-top:30px}.rayo-attribution a{color:var(--r-cyan2)}
@media(max-width:900px){.rayo-bay,.rayo-study-grid{grid-template-columns:1fr}.rayo-study-nav{position:static}.rayo-proof{grid-template-columns:1fr 1fr}.hotel{grid-template-columns:repeat(4,1fr)}.rayo-nav{display:none}}
@media(max-width:560px){.rayo-shell{width:min(100% - 24px,1180px)}.rayo-hero{padding:64px 0 48px;min-height:70vh}.rayo-section{padding:58px 0}.rayo-apparatus,.rayo-controls{padding:18px}.rayo-proof{grid-template-columns:1fr}.hotel{grid-template-columns:repeat(2,1fr)}.rayo-actions{display:grid}.rayo-action{width:100%}.rayo-mapping{grid-template-columns:1fr 40px 1fr}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.rayo-reveal,.room{animation:none!important;transition:none!important}}


/* R19 — full Rayo ten-chapter course architecture */
.rayo-movement{display:inline-flex;gap:8px;align-items:center;border:1px solid rgba(199,167,95,.28);padding:8px 11px;margin-bottom:18px;color:var(--r-gold2);font-size:10px;letter-spacing:.13em;text-transform:uppercase;background:rgba(199,167,95,.035)}
.rayo-cabinet{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin-top:26px}.rayo-cabinet-card{border:1px solid var(--r-line);background:linear-gradient(145deg,rgba(121,208,230,.035),transparent 42%),#090c0e;padding:18px;display:flex;flex-direction:column;gap:10px;min-height:190px}.rayo-cabinet-card.study-only{border-style:dashed;background:rgba(199,167,95,.025)}.rayo-cabinet-card .chapter{font:10px ui-monospace,monospace;letter-spacing:.13em;text-transform:uppercase;color:var(--r-gold2)}.rayo-cabinet-card h3{font-size:26px}.rayo-cabinet-card p{margin:0;color:#c9cecd;font-size:14px;flex:1}.rayo-cabinet-card a{align-self:flex-start;color:var(--r-cyan2);text-decoration:none;font-size:11px;letter-spacing:.09em;text-transform:uppercase}.rayo-cabinet-card a:hover{text-decoration:underline}
.rayo-course-strip{display:grid;grid-template-columns:repeat(10,1fr);gap:5px;margin-top:20px}.rayo-course-strip a{min-height:56px;border:1px solid var(--r-line);display:grid;place-items:center;text-decoration:none;text-align:center;padding:6px;color:var(--r-muted);font:10px ui-monospace,monospace}.rayo-course-strip a:hover,.rayo-course-strip a[aria-current="page"]{border-color:rgba(121,208,230,.5);color:var(--r-cyan2);background:rgba(121,208,230,.04)}
.rayo-thread-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:10px;margin-top:18px}.rayo-thread{border-top:2px solid var(--r-gold);padding:10px 2px;color:#cfd1cd;font-size:12px}.rayo-thread b{display:block;color:var(--r-gold2);font-size:10px;letter-spacing:.12em;text-transform:uppercase;margin-bottom:4px}
.rayo-stage{display:grid;grid-template-columns:repeat(auto-fit,minmax(110px,1fr));gap:8px;margin:18px 0}.rayo-stage .stage{border:1px solid var(--r-line);background:#090c0e;padding:12px;min-height:76px}.rayo-stage .stage b{display:block;color:var(--r-cyan2);font:12px ui-monospace,monospace}.rayo-stage .stage small{color:var(--r-muted)}
.rayo-console{border:1px solid var(--r-line);background:#070a0b;padding:16px;margin-top:16px;font:13px ui-monospace,monospace;white-space:pre-wrap;min-height:84px;color:#d6e8e9}.rayo-meter{height:10px;border:1px solid var(--r-line);background:#07090a;margin:10px 0;overflow:hidden}.rayo-meter>i{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--r-gold),var(--r-cyan));transition:width .35s ease}.rayo-branch{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:14px}.rayo-branch>div{border:1px solid var(--r-line);padding:14px;background:#090c0e}.rayo-branch b{color:var(--r-gold2)}
.rayo-stepper{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px}.rayo-stepper button{border:1px solid var(--r-line);background:#090c0e;color:var(--r-ink);padding:10px 12px}.rayo-stepper button.done{border-color:var(--r-cyan);color:var(--r-cyan2)}
.rayo-logic-row{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:14px 0}.rayo-logic-row>div{border:1px solid var(--r-line);background:#090c0e;padding:14px}.rayo-logic-row b{display:block;color:var(--r-gold2);margin-bottom:4px}
.rayo-chipset{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0}.rayo-chip{border:1px solid var(--r-line);padding:8px 10px;background:#080b0c;color:#d7dcda;font:11px ui-monospace,monospace}.rayo-chip.active{border-color:var(--r-cyan);color:var(--r-cyan2)}
.rayo-warn{border:1px solid rgba(199,167,95,.35);background:rgba(199,167,95,.045);padding:16px;margin:16px 0}.rayo-warn strong{color:var(--r-gold2)}
.rayo-math-table{width:100%;border-collapse:collapse;margin-top:14px;font-size:13px}.rayo-math-table th,.rayo-math-table td{border:1px solid var(--r-line);padding:10px;text-align:left}.rayo-math-table th{color:var(--r-gold2);font-size:10px;letter-spacing:.1em;text-transform:uppercase}.rayo-mini-axis{display:flex;align-items:center;gap:3px;overflow:auto;padding:16px 0}.rayo-mini-axis span{min-width:42px;height:42px;border:1px solid var(--r-line);display:grid;place-items:center;background:#090c0e;font:11px ui-monospace,monospace}.rayo-mini-axis span.limit{border-color:var(--r-gold);color:var(--r-gold2);min-width:58px}.rayo-orbit{display:flex;flex-wrap:wrap;gap:8px;margin:16px 0}.rayo-orbit span{border:1px solid var(--r-line);padding:9px 11px;font:11px ui-monospace,monospace;background:#080b0c}.rayo-orbit span.group-u{border-color:#6a8da0}.rayo-orbit span.group-d{border-color:#9a7857}.rayo-orbit span.group-l{border-color:#728f72}.rayo-orbit span.group-r{border-color:#8d6e8f}
.rayo-transfer{border:1px solid rgba(121,208,230,.25);background:rgba(121,208,230,.025);padding:20px;margin-top:18px}.rayo-transfer h3{font-size:26px}.rayo-source-note{color:var(--r-muted);font-size:11px;border-top:1px solid var(--r-line);padding-top:14px;margin-top:28px}
@media(max-width:900px){.rayo-cabinet{grid-template-columns:1fr}.rayo-course-strip{grid-template-columns:repeat(5,1fr)}.rayo-thread-grid{grid-template-columns:1fr 1fr}.rayo-logic-row{grid-template-columns:1fr}.rayo-branch{grid-template-columns:1fr}}
@media(max-width:560px){.rayo-course-strip{grid-template-columns:repeat(2,1fr)}.rayo-thread-grid{grid-template-columns:1fr}}
@media(prefers-reduced-motion:reduce){.rayo-meter>i{transition:none!important}}


/* R22 — Study Atelier shell / chapter-rail repair */
.rayo-room[data-rayo-mode="study"] .rayo-hero{
  min-height:auto;
  align-items:start;
  padding:70px 0 42px;
  overflow:visible;
}
.rayo-room[data-rayo-mode="study"] .rayo-hero:after{bottom:0;opacity:.38}
.rayo-room[data-rayo-mode="study"] .rayo-hero-copy{max-width:980px}
.rayo-room[data-rayo-mode="study"] h1{font-size:clamp(44px,6vw,84px);max-width:960px}
.rayo-room[data-rayo-mode="study"] .rayo-hero .rayo-lead{margin:18px 0;max-width:860px}
.rayo-room[data-rayo-mode="study"] .rayo-actions{margin-top:22px}
.rayo-room[data-rayo-mode="study"] .rayo-progress{margin-top:20px}
.rayo-room[data-rayo-mode="study"] .rayo-section{padding:64px 0}
.rayo-course-strip{
  grid-template-columns:repeat(5,minmax(0,1fr));
  gap:8px;
  margin-top:16px;
}
.rayo-course-strip a{
  min-height:68px;
  display:flex;
  flex-direction:column;
  align-items:flex-start;
  justify-content:center;
  gap:4px;
  padding:10px 12px;
  text-align:left;
  line-height:1.2;
  overflow:hidden;
}
.rayo-course-strip .rayo-chapter-no{
  display:block;
  color:var(--r-gold2);
  font:9px ui-monospace,monospace;
  letter-spacing:.12em;
}
.rayo-course-strip .rayo-chapter-title{
  display:block;
  color:inherit;
  font:11px/1.25 ui-monospace,monospace;
  overflow-wrap:anywhere;
}
.rayo-course-strip a[aria-current="page"] .rayo-chapter-title{color:var(--r-cyan2)}
@media(max-width:900px){
  .rayo-room[data-rayo-mode="study"] .rayo-hero{padding:58px 0 34px}
  .rayo-course-strip{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:560px){
  .rayo-room[data-rayo-mode="study"] .rayo-hero{padding:44px 0 30px}
  .rayo-room[data-rayo-mode="study"] h1{font-size:clamp(38px,13vw,58px)}
  .rayo-course-strip{grid-template-columns:repeat(2,minmax(0,1fr));gap:6px}
  .rayo-course-strip a{min-height:62px;padding:9px 10px}
  .rayo-course-strip .rayo-chapter-title{font-size:10px}
}