/* ===========================================================
   Smart Valley Tech — shared stylesheet (v2)
   Palette, type, and components carried from v1; extended for
   multi-page structure, active nav, scroll reveals, form states.
   =========================================================== */
:root{
  --ink:#0E1B2A;        /* deep navy ink */
  --slate:#33475B;      /* slate text */
  --mist:#5C6E80;       /* muted */
  --line:#D9E0E7;       /* hairline */
  --paper:#F7F9FB;      /* near-white bg */
  --white:#FFFFFF;
  --accent:#0F8B8D;     /* teal, traceability signal */
  --accent-deep:#0A6E70;
  --gold:#C9A24B;       /* restrained warm accent */
  --maxw:1120px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:'Inter',system-ui,sans-serif;color:var(--slate);background:var(--white) url('../pattern-bg.svg');line-height:1.6;-webkit-font-smoothing:antialiased}
h1,h2,h3,h4{font-family:'Fraunces',Georgia,serif;color:var(--ink);font-weight:500;line-height:1.12;letter-spacing:-0.01em}
a{color:var(--accent-deep);text-decoration:none}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 28px}
.eyebrow{font-family:'IBM Plex Mono',monospace;font-size:.74rem;letter-spacing:.18em;text-transform:uppercase;color:var(--accent-deep)}
.center{text-align:center}

/* ---------- NAV ---------- */
header.nav{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.88);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:68px;max-width:var(--maxw);margin:0 auto;padding:0 28px}
.brand{display:flex;align-items:center;gap:11px;font-family:'Fraunces',serif;font-weight:600;color:var(--ink);font-size:1.12rem;letter-spacing:-0.01em}
.brand .mark{width:26px;height:26px;flex:0 0 26px}
.nav-links{display:flex;gap:30px;align-items:center}
.nav-links a{color:var(--slate);font-size:.92rem;font-weight:500;position:relative}
.nav-links a:hover{color:var(--accent-deep)}
.nav-links a.active{color:var(--accent-deep)}
.nav-links a.active::after{content:"";position:absolute;left:0;right:0;bottom:-24px;height:2px;background:var(--accent)}
.nav-links a.nav-cta{background:var(--ink);color:#fff;padding:9px 18px;border-radius:6px;font-size:.9rem}
.nav-links a.nav-cta:hover{background:var(--accent-deep);color:#fff}
.nav-links a.nav-cta.active::after{display:none}
.nav-toggle{display:none;background:none;border:0;cursor:pointer;flex-direction:column;gap:5px}
.nav-toggle span{width:24px;height:2px;background:var(--ink);display:block;transition:.25s}

/* ---------- HERO (home) ---------- */
.hero{position:relative;overflow:hidden;background:#16344A url('../hero-bg.svg') center/cover no-repeat;color:#fff}
.hero .wrap{position:relative;z-index:2;padding-top:96px;padding-bottom:104px}
.hero-grid{display:grid;grid-template-columns:1.45fr .9fr;gap:54px;align-items:center}
.hero h1{color:#fff;font-size:clamp(2.3rem,5vw,3.7rem);font-weight:500;text-shadow:0 2px 22px rgba(7,20,30,.5)}
.hero h1 em{font-style:italic;color:#8FD6D2}
.hero p.lede{margin-top:22px;font-size:1.12rem;color:#CDD9E2;max-width:33em;text-shadow:0 1px 14px rgba(7,20,30,.45)}
.hero .eyebrow{color:#7Fd1cd}
.hero-cta{margin-top:34px;display:flex;gap:14px;flex-wrap:wrap}

/* ---------- PAGE HERO (interior) ---------- */
.page-hero{position:relative;overflow:hidden;background:#16344A url('../hero-bg.svg') center/cover no-repeat;color:#fff}
.page-hero .wrap{position:relative;z-index:2;padding:72px 28px 78px}
.page-hero .eyebrow{color:#7Fd1cd}
.page-hero h1{color:#fff;font-size:clamp(2rem,4.4vw,3rem);margin-top:12px;text-shadow:0 2px 22px rgba(7,20,30,.5)}
.page-hero p{margin-top:18px;font-size:1.1rem;color:#CDD9E2;max-width:44ch;text-shadow:0 1px 14px rgba(7,20,30,.4)}

.btn{display:inline-block;padding:13px 24px;border-radius:7px;font-weight:600;font-size:.95rem;cursor:pointer;border:1px solid transparent;transition:.18s}
.btn-primary{background:var(--accent);color:#fff}
.btn-primary:hover{background:#13a0a2}
.btn-ghost{background:transparent;color:#fff;border-color:rgba(255,255,255,.35)}
.btn-ghost:hover{border-color:#fff}
.btn-dark{background:var(--ink);color:#fff}
.btn-dark:hover{background:var(--accent-deep)}

.hero-card{background:rgba(8,23,33,.42);border:1px solid rgba(255,255,255,.16);border-radius:14px;padding:26px;backdrop-filter:blur(3px);-webkit-backdrop-filter:blur(3px)}
.hero-card .label{font-family:'IBM Plex Mono',monospace;font-size:.7rem;letter-spacing:.15em;text-transform:uppercase;color:#7Fd1cd}
.hero-card ul{list-style:none;margin-top:14px}
.hero-card li{padding:11px 0;border-bottom:1px solid rgba(255,255,255,.10);color:#D7E1EA;font-size:.96rem;display:flex;align-items:center;gap:10px}
.hero-card li:last-child{border-bottom:0}
.hero-card li svg{flex:0 0 16px}

/* ---------- SECTIONS ---------- */
section{padding:84px 0}
.section-head{max-width:62ch;margin-bottom:46px}
.section-head.center{margin-left:auto;margin-right:auto}
.section-head h2{font-size:clamp(1.8rem,3.4vw,2.6rem);margin-top:12px}
.section-head p{margin-top:16px;font-size:1.06rem;color:var(--mist)}
.alt{background:var(--paper) url('../pattern-bg.svg')}
.vdiv{height:58px;margin:-44px 0 24px;background:url('../valley-divider.svg') center bottom/100% 100% no-repeat;pointer-events:none}

/* value / cards */
.cols{display:grid;grid-template-columns:repeat(3,1fr);gap:26px}
.card{background:var(--white);border:1px solid var(--line);border-radius:12px;padding:28px;transition:.2s}
.alt .card{background:#fff}
.card:hover{border-color:var(--accent);transform:translateY(-3px);box-shadow:0 14px 30px -18px rgba(14,27,42,.35)}
.card .num{font-family:'IBM Plex Mono',monospace;font-size:.72rem;letter-spacing:.14em;color:var(--accent-deep)}
.card h3{font-size:1.24rem;margin:12px 0 9px}
.card p{font-size:.96rem;color:var(--mist)}

/* about */
.about-grid{display:grid;grid-template-columns:.85fr 1.15fr;gap:50px;align-items:start}
.about-body p{margin-bottom:16px}
.about-body p.big{font-size:1.18rem;color:var(--ink);font-family:'Fraunces',serif;line-height:1.4}
.facts{display:flex;flex-wrap:wrap;gap:14px;margin-top:24px}
.fact{border:1px solid var(--line);border-radius:8px;padding:12px 16px;background:#fff}
.fact b{display:block;font-family:'Fraunces',serif;font-size:1.5rem;color:var(--ink)}
.fact small{color:var(--mist);font-size:.82rem}

/* services */
.svc{display:grid;grid-template-columns:repeat(2,1fr);gap:24px}
.svc-item{border:1px solid var(--line);border-radius:12px;padding:26px;background:#fff;position:relative;transition:.2s}
.svc-item:hover{border-color:var(--accent);box-shadow:0 14px 30px -20px rgba(14,27,42,.3)}
.svc-item h3{font-size:1.18rem;margin-bottom:8px;display:flex;align-items:center;gap:10px}
.svc-item p{font-size:.95rem;color:var(--mist)}
.svc-item .dot{width:9px;height:9px;border-radius:50%;background:var(--accent);flex:0 0 9px}
.cap{list-style:none;margin-top:16px;display:grid;grid-template-columns:1fr 1fr;gap:9px 28px}
.cap li{font-size:.92rem;color:var(--mist);padding-left:17px;position:relative;line-height:1.5}
.cap li::before{content:"";position:absolute;left:0;top:.5em;width:6px;height:6px;border-radius:50%;background:var(--accent)}
.cap li b{color:var(--ink);font-weight:600}

/* thought leadership / IP */
.tl{display:grid;grid-template-columns:repeat(2,1fr);gap:24px}
.tl-card{border:1px solid var(--line);border-radius:12px;padding:30px;background:#fff;transition:.2s}
.tl-card:hover{border-color:var(--accent);box-shadow:0 14px 30px -20px rgba(14,27,42,.3)}
.tl-card .tag{font-family:'IBM Plex Mono',monospace;font-size:.7rem;letter-spacing:.14em;text-transform:uppercase;color:var(--gold)}
.tl-card h3{font-size:1.4rem;margin:12px 0 10px}
.tl-card p{font-size:.97rem;color:var(--mist);margin-bottom:16px}
.tl-card a.more{font-weight:600;font-size:.92rem;display:inline-flex;align-items:center;gap:6px}

/* writing list (insights) */
.writing{display:grid;gap:16px;margin-top:8px}
.write-item{display:flex;justify-content:space-between;align-items:baseline;gap:20px;border:1px solid var(--line);border-radius:12px;padding:22px 26px;background:#fff;transition:.2s}
.write-item:hover{border-color:var(--accent);box-shadow:0 14px 30px -20px rgba(14,27,42,.3)}
.write-item .wt h3{font-size:1.16rem;margin-bottom:6px}
.write-item .wt p{font-size:.92rem;color:var(--mist)}
.write-item .kind{font-family:'IBM Plex Mono',monospace;font-size:.68rem;letter-spacing:.14em;text-transform:uppercase;color:var(--accent-deep);white-space:nowrap;flex:0 0 auto}

/* CTA band */
.cta-band{background:var(--ink) url('../footer-bg.svg') center/cover no-repeat;color:#fff;border-radius:16px;padding:46px 44px;display:flex;justify-content:space-between;align-items:center;gap:26px;flex-wrap:wrap}
.cta-band h2{color:#fff;font-size:clamp(1.5rem,3vw,2rem)}
.cta-band p{color:#B9C7D4;margin-top:8px;max-width:46ch}

/* preview links (home) */
.more-link{font-weight:600;font-size:.95rem;display:inline-flex;align-items:center;gap:7px;margin-top:22px}
.two-col{display:grid;grid-template-columns:1fr 1fr;gap:24px;align-items:stretch}

/* contact */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:50px;align-items:start}
.contact-info p{margin-bottom:18px;color:var(--mist)}
.contact-info .email{font-family:'Fraunces',serif;font-size:1.4rem;color:var(--ink)}
form .row{display:grid;grid-template-columns:1fr 1fr;gap:16px}
form label{display:block;font-size:.82rem;font-weight:600;color:var(--ink);margin:0 0 6px}
form input,form textarea{width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:8px;font-family:inherit;font-size:.95rem;color:var(--ink);background:#fff;margin-bottom:16px}
form input:focus,form textarea:focus{outline:2px solid var(--accent);border-color:transparent}
form textarea{min-height:130px;resize:vertical}
.form-status{margin-top:14px;padding:13px 16px;border-radius:8px;font-size:.92rem;display:none}
.form-status.show{display:block}
.form-status.ok{background:rgba(15,139,141,.10);border:1px solid var(--accent);color:var(--accent-deep)}
.form-status.err{background:#FCEEEE;border:1px solid #E4B4B4;color:#9A3B3B}

/* 404 */
.notfound{min-height:56vh;display:flex;align-items:center;justify-content:center;text-align:center;padding:80px 28px}
.notfound .code{font-family:'IBM Plex Mono',monospace;color:var(--accent-deep);letter-spacing:.2em;font-size:.8rem;text-transform:uppercase}
.notfound h1{font-size:clamp(2rem,5vw,3rem);margin:14px 0 12px}
.notfound p{color:var(--mist);max-width:44ch;margin:0 auto 26px}

/* footer */
footer{background:#0E1B2A url('../footer-bg.svg') center/cover no-repeat;color:#A9BACA;padding:50px 0 34px}
footer .f-grid{display:flex;justify-content:space-between;align-items:center;gap:24px;flex-wrap:wrap}
footer .brand{color:#fff}
footer a{color:#A9BACA}
footer a:hover{color:#fff}
footer .legal{font-size:.84rem;color:#6E8197;margin-top:18px;border-top:1px solid rgba(255,255,255,.08);padding-top:18px}

/* scroll reveal */
.reveal{opacity:0;transform:translateY(16px);transition:opacity .6s ease,transform .6s ease}
.reveal.in{opacity:1;transform:none}

@media (max-width:860px){
  .hero-grid{grid-template-columns:1fr;gap:38px}
  .cols{grid-template-columns:1fr}
  .about-grid{grid-template-columns:1fr;gap:30px}
  .svc,.tl,.contact-grid,.cap,.two-col{grid-template-columns:1fr}
  .nav-links{position:fixed;inset:68px 0 auto 0;background:#fff;flex-direction:column;align-items:flex-start;padding:18px 28px;gap:18px;border-bottom:1px solid var(--line);transform:translateY(-130%);transition:.25s;box-shadow:0 20px 30px -20px rgba(0,0,0,.25)}
  .nav-links.open{transform:translateY(0)}
  .nav-links a.active::after{display:none}
  .nav-toggle{display:flex}
  form .row{grid-template-columns:1fr}
  .cta-band{padding:34px 28px}
}
@media (prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}.reveal{opacity:1;transform:none}}

/* ============ BOOK / FET FEATURE ============ */
.book-hero{background:var(--ink);color:#fff;padding:76px 0 84px;position:relative;overflow:hidden}
.book-hero::before{content:"";position:absolute;inset:0;background:radial-gradient(120% 80% at 78% 12%,rgba(15,139,141,.18),transparent 60%);pointer-events:none}
.book-hero .wrap{position:relative}
.book-grid{display:grid;grid-template-columns:minmax(0,340px) 1fr;gap:56px;align-items:center}
.book-cover-wrap{perspective:1600px}
.book-cover{width:100%;height:auto;border-radius:6px;display:block;box-shadow:0 40px 70px -30px rgba(0,0,0,.7),0 10px 24px -12px rgba(0,0,0,.5);transform:rotateY(-9deg) rotateX(1.5deg);transition:transform .5s ease}
.book-cover-wrap:hover .book-cover{transform:rotateY(0deg)}
.book-hero .eyebrow{color:var(--gold)}
.book-hero h1{color:#fff;font-size:clamp(2.1rem,4.6vw,3.2rem);margin:12px 0 8px}
.book-hero .subtitle{color:#C7D2DD;font-size:1.15rem;font-family:'Fraunces',serif;font-style:italic;margin-bottom:22px}
.book-hero .vol{font-family:'IBM Plex Mono',monospace;font-size:.74rem;letter-spacing:.22em;text-transform:uppercase;color:var(--gold);display:inline-block;margin-bottom:6px}
.book-meta{display:flex;gap:10px;flex-wrap:wrap;margin-top:26px}
.book-meta span{font-family:'IBM Plex Mono',monospace;font-size:.72rem;letter-spacing:.08em;color:#9FB0BF;border:1px solid rgba(255,255,255,.16);border-radius:20px;padding:6px 14px}
.book-cta-row{display:flex;gap:14px;flex-wrap:wrap;margin-top:30px}

/* trailer / teaser */
.trailer{background:var(--ink);color:#E8EEF3;padding:0 0 82px}
.trailer .wrap{max-width:760px}
.trailer-card{border-left:2px solid var(--gold);padding:6px 0 6px 30px}
.trailer p{font-family:'Fraunces',Georgia,serif;font-size:1.24rem;line-height:1.62;color:#DCE4EB;margin-bottom:18px}
.trailer p:last-child{margin-bottom:0}
.trailer .lede{font-size:1.4rem;color:#fff}
.trailer .close-line{color:var(--gold);font-style:italic}

/* about the book */
.book-about .two{display:grid;grid-template-columns:1.5fr 1fr;gap:48px}
.book-about blockquote{font-family:'Fraunces',serif;font-size:1.2rem;line-height:1.5;color:var(--ink);border-left:3px solid var(--gold);padding-left:22px;margin:0}
.book-about cite{display:block;margin-top:14px;font-style:normal;font-family:'IBM Plex Mono',monospace;font-size:.78rem;letter-spacing:.06em;color:var(--mist)}

/* TOC */
.toc-wrap{display:grid;grid-template-columns:1fr 1fr;gap:14px 40px}
.toc-part{grid-column:1/-1;font-family:'IBM Plex Mono',monospace;font-size:.74rem;letter-spacing:.16em;text-transform:uppercase;color:var(--gold);margin-top:20px;padding-bottom:8px;border-bottom:1px solid var(--line)}
.toc-part:first-child{margin-top:0}
.toc-item{display:flex;gap:14px;align-items:baseline;padding:7px 0;border-bottom:1px dotted var(--line)}
.toc-num{font-family:'IBM Plex Mono',monospace;font-size:.8rem;color:var(--accent);min-width:26px}
.toc-title{color:var(--slate);font-size:.98rem}
.toc-note{color:var(--mist);font-size:.86rem;font-style:italic;margin-top:8px;grid-column:1/-1}

/* request access form */
.request-band{background:var(--paper) url('../pattern-bg.svg');border:1px solid var(--line);border-radius:16px;padding:44px;max-width:620px;margin:0 auto}
.request-band h2{margin-bottom:8px}
.access-note{font-size:.9rem;color:var(--mist);margin:6px 0 24px}
.gate-legend{display:flex;gap:20px;flex-wrap:wrap;margin-top:16px;font-size:.86rem;color:var(--mist)}
.gate-legend b{color:var(--ink);font-weight:600}
.gate-open{color:var(--accent-deep)}

@media (max-width:860px){
  .book-grid{grid-template-columns:1fr;gap:36px;text-align:center}
  .book-cover-wrap{max-width:280px;margin:0 auto}
  .book-cover{transform:none}
  .book-meta,.book-cta-row{justify-content:center}
  .book-about .two{grid-template-columns:1fr;gap:28px}
  .toc-wrap{grid-template-columns:1fr}
  .trailer-card{padding-left:20px}
  .request-band{padding:30px 22px}
}

/* homepage book teaser band */
.book-band{background:var(--ink);color:#fff;position:relative;overflow:hidden}
.book-band::before{content:"";position:absolute;inset:0;background:radial-gradient(100% 90% at 15% 20%,rgba(15,139,141,.16),transparent 55%);pointer-events:none}
.book-band .wrap{position:relative}
.book-band-grid{display:grid;grid-template-columns:200px 1fr auto;gap:40px;align-items:center}
.book-band img{width:200px;height:auto;border-radius:5px;box-shadow:0 24px 44px -22px rgba(0,0,0,.7);display:block}
.book-band .eyebrow{color:var(--gold)}
.book-band h2{color:#fff;margin:8px 0 10px}
.book-band p{color:#C7D2DD;max-width:56ch}
@media (max-width:860px){
  .book-band-grid{grid-template-columns:1fr;text-align:center;gap:26px;justify-items:center}
  .book-band p{max-width:none}
}




/* ============ BOOK SEAL (hero, floating, clickable) ============ */
.hero .wrap{position:relative}
.book-seal{position:absolute;top:2px;right:12px;z-index:4;display:block;text-decoration:none;transition:transform .3s ease;cursor:pointer;width:150px;height:150px}
.book-seal:hover{transform:scale(1.04)}
.book-seal svg{display:block;filter:drop-shadow(0 10px 22px rgba(0,0,0,.45))}
.bs-ticks{transform-origin:110px 110px;animation:bsspin 26s linear infinite}
@keyframes bsspin{to{transform:rotate(360deg)}}
.bs-shine{animation:bspulse 2.6s ease-in-out infinite}
@keyframes bspulse{0%,100%{opacity:.45}50%{opacity:1}}
.bs-explore{position:absolute;left:50%;bottom:-14px;transform:translateX(-50%);font-family:'IBM Plex Mono',monospace;font-size:.68rem;letter-spacing:.1em;text-transform:uppercase;color:var(--gold);background:rgba(14,27,42,.95);border:1px solid var(--gold);border-radius:20px;padding:5px 15px;white-space:nowrap;transition:.2s}
.book-seal:hover .bs-explore{background:var(--gold);color:var(--ink)}
@media (max-width:980px){
  .hero .wrap{display:flex;flex-direction:column}
  .hero-grid{order:2}
  .book-seal{position:static;order:1;margin:0 auto 22px;top:auto;right:auto;width:150px}
}
@media (prefers-reduced-motion:reduce){.bs-ticks,.bs-shine{animation:none}}

/* ===========================================================
   ARTICLE PAGES (research papers) — added v4
   =========================================================== */
.article{max-width:74ch;margin:0 auto;padding:0 28px}
.article > section{padding:0}
.article-body{padding:64px 0 20px}
.article-body p{font-size:1.06rem;color:var(--slate);margin-bottom:20px}
.article-body h2{font-size:clamp(1.45rem,2.8vw,1.95rem);margin:52px 0 18px}
.article-body h3{font-size:1.2rem;margin:34px 0 12px}
.article-body strong{color:var(--ink);font-weight:600}
.article-body em{font-style:italic}
.lede-para{font-size:1.2rem !important;color:var(--ink) !important;line-height:1.55}
.pull{border-left:3px solid var(--accent);padding:4px 0 4px 22px;margin:34px 0;font-family:'Fraunces',Georgia,serif;font-size:1.25rem;color:var(--ink);line-height:1.4}
.article-meta{font-family:'IBM Plex Mono',monospace;font-size:.72rem;letter-spacing:.14em;text-transform:uppercase;color:var(--mist);margin-bottom:8px}
.split{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin:30px 0}
.split .sp{border:1px solid var(--line);border-radius:12px;padding:22px 24px;background:#fff}
.split .sp h4{font-family:'IBM Plex Mono',monospace;font-size:.7rem;letter-spacing:.14em;text-transform:uppercase;margin-bottom:10px}
.split .sp.safe h4{color:var(--accent-deep)}
.split .sp.trap h4{color:var(--gold)}
.split .sp p{font-size:.95rem;color:var(--mist);margin:0}
.laws{list-style:none;margin:26px 0}
.laws li{border-top:1px solid var(--line);padding:20px 0}
.laws li:last-child{border-bottom:1px solid var(--line)}
.laws b{display:block;font-family:'Fraunces',Georgia,serif;font-weight:600;font-size:1.1rem;color:var(--ink);margin-bottom:7px}
.laws span{font-size:.98rem;color:var(--mist)}

/* ---------- DOI CARD: an in-doubt transaction that resolves ---------- */
.doi-card{display:block;max-width:640px;margin:44px auto 0;background:#fff;border:1px solid var(--line);border-radius:12px;padding:26px 28px 22px;position:relative;overflow:hidden;transition:border-color .45s ease,box-shadow .45s ease,transform .45s ease}
.doi-card:hover,.doi-card:focus-visible{border-color:var(--accent);box-shadow:0 18px 40px -22px rgba(14,27,42,.45);transform:translateY(-2px);outline:none}
.doi-card:focus-visible{outline:2px solid var(--accent);outline-offset:3px}
.doi-status{display:flex;align-items:center;gap:9px;font-family:'IBM Plex Mono',monospace;font-size:.68rem;letter-spacing:.14em;text-transform:uppercase;font-weight:500;color:var(--gold);transition:color .45s ease;margin-bottom:14px}
.doi-card:hover .doi-status,.doi-card:focus-visible .doi-status{color:var(--accent-deep)}
.doi-dot{width:7px;height:7px;border-radius:50%;background:var(--gold);animation:doubtPulse 1.7s ease-in-out infinite;transition:background .45s ease;flex:none}
.doi-card:hover .doi-dot,.doi-card:focus-visible .doi-dot{background:var(--accent);animation:none}
@keyframes doubtPulse{0%,100%{opacity:1;box-shadow:0 0 0 0 rgba(201,162,75,.5)}50%{opacity:.5;box-shadow:0 0 0 7px rgba(201,162,75,0)}}
.doi-status .lbl-ok{display:none}
.doi-card:hover .lbl-doubt,.doi-card:focus-visible .lbl-doubt{display:none}
.doi-card:hover .lbl-ok,.doi-card:focus-visible .lbl-ok{display:inline}
.doi-card h3{font-size:1.35rem;margin:0 0 6px}
.doi-card .doi-sub{font-size:.95rem;color:var(--mist);margin:0 0 22px}
.doi-channel{position:relative;height:24px;margin-bottom:18px}
.doi-wire{position:absolute;top:50%;left:0;right:0;height:1px;background:repeating-linear-gradient(90deg,var(--line) 0 6px,transparent 6px 12px);transition:opacity .45s ease}
.doi-card:hover .doi-wire,.doi-card:focus-visible .doi-wire{background:var(--accent);opacity:.3}
.doi-packet{position:absolute;top:50%;left:0;width:22px;height:6px;border-radius:2px;background:var(--gold);transform:translateY(-50%);animation:travel 3s cubic-bezier(.5,0,.5,1) infinite;transition:background .45s ease}
.doi-card:hover .doi-packet,.doi-card:focus-visible .doi-packet{background:var(--accent);animation:arrive .5s cubic-bezier(.2,.8,.3,1) forwards}
@keyframes travel{0%{left:0;opacity:0}12%{opacity:1}60%{left:calc(100% - 22px);opacity:1}70%{left:calc(100% - 22px);opacity:0}100%{left:0;opacity:0}}
@keyframes arrive{to{left:calc(100% - 22px);opacity:1}}
.doi-endpoint{position:absolute;top:50%;right:0;width:9px;height:9px;border:1.5px solid var(--line);border-radius:50%;background:#fff;transform:translateY(-50%);transition:border-color .45s ease,background .45s ease}
.doi-card:hover .doi-endpoint,.doi-card:focus-visible .doi-endpoint{border-color:var(--accent);background:var(--accent)}
.doi-foot{display:flex;align-items:center;justify-content:space-between;gap:16px;border-top:1px solid var(--line);padding-top:16px}
.doi-id{font-family:'IBM Plex Mono',monospace;font-size:.76rem;color:var(--mist);word-break:break-all}
.doi-cta{display:inline-flex;align-items:center;gap:7px;font-size:.93rem;font-weight:600;color:var(--ink);white-space:nowrap;transition:color .45s ease}
.doi-card:hover .doi-cta,.doi-card:focus-visible .doi-cta{color:var(--accent-deep)}
.doi-arrow{display:inline-block;transition:transform .45s cubic-bezier(.2,.8,.3,1)}
.doi-card:hover .doi-arrow,.doi-card:focus-visible .doi-arrow{transform:translateX(5px)}

@media (max-width:760px){
  .split{grid-template-columns:1fr}
  .doi-foot{flex-direction:column;align-items:flex-start;gap:10px}
  .article-body{padding-top:44px}
}
@media (prefers-reduced-motion:reduce){
  .doi-dot,.doi-packet{animation:none}
  .doi-packet{left:calc(100% - 22px);opacity:1}
  .doi-card,.doi-arrow,.doi-status,.doi-cta{transition:none}
}

/* ---------- ARTICLE + STICKY PAPER RAIL (v4.1) ---------- */
.article-layout{display:grid;grid-template-columns:minmax(0,1fr) 324px;gap:54px;align-items:start;max-width:var(--maxw);margin:0 auto;padding:0 28px}
.article-layout .article-body{padding:56px 0 20px;max-width:68ch}
.paper-rail{position:sticky;top:92px;padding-top:56px}
.rail-point{display:flex;justify-content:center;margin-bottom:10px}
.rail-arrow{width:38px;height:60px;animation:bob 1.5s ease-in-out infinite;filter:drop-shadow(0 6px 10px rgba(168,132,47,.35))}
@keyframes bob{0%,100%{transform:translateY(0)}50%{transform:translateY(7px)}}
.paper-rail .doi-card{margin:0;max-width:none;padding:22px 22px 18px}
.paper-rail .doi-card h3{font-size:1.12rem}
.paper-rail .doi-card .doi-sub{font-size:.86rem;margin-bottom:18px}
.paper-rail .doi-foot{flex-direction:column;align-items:flex-start;gap:9px}
.paper-rail .doi-id{font-size:.7rem}
@media (max-width:980px){
  .article-layout{grid-template-columns:1fr;gap:0}
  .paper-rail{position:static;padding-top:38px;order:-1}
  .article-layout .article-body{padding-top:34px}
  .rail-point{justify-content:center}
  .rail-arrow{width:32px;height:50px}
}
@media (prefers-reduced-motion:reduce){.rail-arrow{animation:none}}