/* HERD infrasound library — shared styles */
:root{--ink:#0a1624;--ink-2:#0e1f33;--ink-3:#13293f;--teal:#2dd4c8;--gold:#f0a843;--muted:#8fa3b8;--line:rgba(143,163,184,.16);--green:#4ade80;--blue:#60a5fa;--violet:#a78bfa;--max:880px}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:"Avenir Next","Segoe UI",system-ui,-apple-system,sans-serif;background:var(--ink);color:#e8eef4;line-height:1.7;-webkit-font-smoothing:antialiased}
h1,h2,h3{font-weight:800;line-height:1.18;letter-spacing:-.01em}
a{color:var(--teal)}
.wrap{max-width:var(--max);margin:0 auto;padding:0 22px}

/* nav */
nav.top{position:fixed;top:0;left:0;right:0;z-index:50;background:rgba(10,22,36,.85);backdrop-filter:blur(12px);border-bottom:1px solid rgba(255,255,255,.06)}
nav.top .wrap{max-width:1100px;display:flex;align-items:center;justify-content:space-between;height:62px}
.logo{display:flex;align-items:center;gap:9px;font-size:20px;font-weight:800;letter-spacing:.14em;color:#fff;text-decoration:none}
.logo span{color:var(--teal)}
.logo img{height:28px;width:28px;display:block}
nav.top .links{display:flex;align-items:center}
nav.top .links a{color:var(--muted);text-decoration:none;font-size:13px;margin-left:18px;white-space:nowrap}
nav.top .links a:hover{color:#fff}
nav.top .links .cta{color:var(--teal);font-weight:600}
.nav-toggle{display:none;background:none;border:0;cursor:pointer;width:42px;height:42px;padding:9px;margin-left:10px}
.nav-toggle span{display:block;width:100%;height:2px;background:#e8eef4;border-radius:2px;transition:transform .25s,opacity .2s}
.nav-toggle span+span{margin-top:5px}
nav.top.open .nav-toggle span:nth-child(1){transform:translateY(7px) rotate(45deg)}
nav.top.open .nav-toggle span:nth-child(2){opacity:0}
nav.top.open .nav-toggle span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}
@media(max-width:900px){
  .nav-toggle{display:block}
  nav.top .wrap{position:relative}
  nav.top .links{position:absolute;top:62px;left:0;right:0;flex-direction:column;align-items:stretch;background:rgba(10,22,36,.98);backdrop-filter:blur(14px);border-bottom:1px solid rgba(255,255,255,.08);padding:6px 0 12px;display:none}
  nav.top.open .links{display:flex}
  nav.top .links a{margin:0;padding:14px 24px;font-size:16px;border-top:1px solid rgba(255,255,255,.05)}
}

/* hero */
header.hero{position:relative;min-height:62vh;display:flex;align-items:flex-end;background-size:cover;background-position:center;padding-bottom:48px;padding-top:90px}
header.hero.tall{min-height:78vh}
header.hero .wrap{position:relative;z-index:2}
.eyebrow{display:inline-block;font-size:12px;letter-spacing:.2em;text-transform:uppercase;color:var(--teal);border:1px solid rgba(45,212,200,.4);border-radius:999px;padding:6px 14px;margin-bottom:18px}
.eyebrow.violet{color:var(--violet);border-color:rgba(167,139,250,.45);background:rgba(167,139,250,.08)}
header.hero h1{font-size:clamp(30px,5.4vw,54px);max-width:16ch}
header.hero h1 em{font-style:normal;color:var(--teal)}
header.hero .sub{color:#cdd9e4;font-size:clamp(16px,2.3vw,21px);margin-top:18px;max-width:52ch}

/* breadcrumb */
.crumb{font-size:13px;color:var(--muted);margin-bottom:14px}
.crumb a{color:var(--muted);text-decoration:none}
.crumb a:hover{color:var(--teal)}

/* article */
article{padding:52px 0 30px}
.seg{font-size:12px;letter-spacing:.18em;text-transform:uppercase;color:var(--gold);font-weight:700;margin:0 0 6px}
h2{font-size:clamp(23px,3.6vw,32px);margin:42px 0 4px;scroll-margin-top:80px}
h2:first-child{margin-top:0}
p.body{font-size:17.5px;color:#dbe6f0;margin:16px 0}
p.body b{color:#fff}
.ref{color:var(--teal);font-size:13px;vertical-align:super;text-decoration:none;font-weight:700;margin-left:1px}
.lead{font-size:19px;color:#e3ecf4;margin:6px 0 8px}

figure{margin:24px 0}
figure img{width:100%;border-radius:16px;display:block;border:1px solid var(--line)}
figcaption{color:var(--muted);font-size:13.5px;margin-top:10px;text-align:center}

.scale{margin:22px 0;border:1px solid var(--line);border-radius:16px;overflow:hidden;background:var(--ink-2)}
.scale .row{display:flex;align-items:center;gap:14px;padding:13px 18px;border-bottom:1px solid var(--line);font-size:15px}
.scale .row:last-child{border-bottom:0}
.scale .hz{flex:none;width:120px;font-weight:800;color:var(--teal);font-variant-numeric:tabular-nums}
.scale .row.us{background:rgba(45,212,200,.07)}
.scale .row.us .hz{color:var(--gold)}
.scale .lbl{color:#cdd9e4}

ul.facts{list-style:none;display:grid;gap:13px;margin:20px 0}
ul.facts li{position:relative;padding:16px 18px 16px 52px;border:1px solid var(--line);border-radius:14px;background:var(--ink-2);font-size:16px;color:#dbe6f0}
ul.facts li b{color:#fff}
ul.facts li .e{position:absolute;left:16px;top:14px;font-size:22px}
ul.list{list-style:none;display:grid;gap:11px;margin:18px 0}
ul.list li{position:relative;padding-left:24px;font-size:16.5px;color:#dbe6f0}
ul.list li::before{content:"";position:absolute;left:2px;top:9px;width:9px;height:9px;border-radius:3px;border:1.5px solid var(--teal)}
ul.list li b{color:#fff}

.story{border-left:3px solid var(--gold);background:rgba(240,168,67,.06);border-radius:0 14px 14px 0;padding:18px 22px;margin:22px 0}
.story .h{color:var(--gold);font-weight:800;font-size:14px;letter-spacing:.04em;text-transform:uppercase;margin-bottom:6px}
.story p{font-size:16px;color:#e3ecf4}
.didyou{border:1px dashed rgba(45,212,200,.45);border-radius:16px;padding:20px 22px;margin:22px 0;background:rgba(45,212,200,.05)}
.didyou .h{color:var(--teal);font-weight:800;font-size:13px;letter-spacing:.08em;text-transform:uppercase;margin-bottom:10px}
.didyou ul{list-style:none;display:grid;gap:10px}
.didyou li{padding-left:24px;position:relative;font-size:15.5px;color:#dbe6f0}
.didyou li::before{content:"→";position:absolute;left:0;color:var(--teal);font-weight:800}
.herd{border:1px solid rgba(45,212,200,.35);border-radius:16px;padding:18px 20px;margin:22px 0;background:linear-gradient(180deg,rgba(45,212,200,.06),transparent)}
.herd .h{color:var(--teal);font-weight:800;font-size:13px;letter-spacing:.06em;text-transform:uppercase;margin-bottom:6px}
.herd p{color:#dbe6f0;font-size:15.5px;margin:0}
.callout{border-radius:14px;padding:16px 18px;margin:20px 0;border:1px solid var(--line);background:var(--ink-2)}
.callout.warn{border-color:rgba(240,168,67,.4);background:rgba(240,168,67,.07)}
.callout.ok{border-color:rgba(74,222,128,.4);background:rgba(74,222,128,.06)}
.callout.info{border-color:rgba(96,165,250,.35);background:rgba(96,165,250,.07)}
.callout .t{font-weight:800;margin-bottom:5px;font-size:14.5px}
.callout.warn .t{color:var(--gold)}.callout.ok .t{color:var(--green)}.callout.info .t{color:var(--blue)}
.callout p{color:#cdd9e4;font-size:14.5px}
.pull{font-size:clamp(21px,3.2vw,28px);font-weight:800;color:#fff;line-height:1.3;margin:30px 0;text-align:center}
.pull em{font-style:normal;color:var(--teal)}

/* hub grid */
.hubgrid{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:26px 0}
@media(max-width:680px){.hubgrid{grid-template-columns:1fr}}
.acard{display:block;border:1px solid var(--line);border-radius:16px;padding:22px;background:var(--ink-2);text-decoration:none;color:inherit;transition:border-color .15s,transform .15s}
.acard:hover{border-color:rgba(45,212,200,.5);transform:translateY(-2px)}
.acard .n{font-size:12px;color:var(--muted);font-weight:700;letter-spacing:.06em}
.acard h3{font-size:19px;color:#fff;margin:6px 0 6px}
.acard p{font-size:14.5px;color:#b8c7d6}
.acard .go{color:var(--teal);font-size:13.5px;font-weight:700;margin-top:10px;display:inline-block}

/* prev/next */
.prevnext{display:flex;justify-content:space-between;gap:14px;margin:36px 0 0;flex-wrap:wrap}
.prevnext a{flex:1;min-width:200px;border:1px solid var(--line);border-radius:14px;padding:16px 18px;text-decoration:none;background:var(--ink-2)}
.prevnext a:hover{border-color:rgba(45,212,200,.5)}
.prevnext .d{font-size:12px;color:var(--muted)}
.prevnext .t{color:#fff;font-weight:700;font-size:15px;margin-top:3px}
.prevnext a.next{text-align:right}

/* CTA */
.cta-box{border:1px solid rgba(45,212,200,.4);border-radius:20px;padding:32px 26px;text-align:center;background:linear-gradient(180deg,rgba(45,212,200,.08),rgba(45,212,200,.02));margin:34px 0 10px}
.cta-box h2{margin:0 0 10px}
.cta-box p{color:#cdd9e4;font-size:16px;max-width:48ch;margin:0 auto 22px}
.btn{display:inline-block;background:var(--teal);color:var(--ink);font-weight:800;padding:14px 28px;border-radius:10px;text-decoration:none;font-size:16px}
.btn:hover{transform:translateY(-2px)}
.btn-ghost{background:transparent;color:var(--teal);border:1.5px solid rgba(45,212,200,.5);margin-left:8px}

/* glossary */
.glossary{display:grid;gap:10px;margin:20px 0}
.glossary dt{color:#fff;font-weight:800;font-size:15.5px}
.glossary dd{color:#b8c7d6;font-size:15px;margin:2px 0 10px}

/* references / bibliography */
.refs{border-top:1px solid var(--line);margin-top:30px;padding-top:24px}
.refs h2{font-size:21px;margin-top:0}
ol.bib{margin:14px 0 0;padding-left:0;list-style:none;counter-reset:b}
ol.bib li{counter-increment:b;position:relative;padding:12px 14px 12px 44px;border:1px solid var(--line);border-radius:12px;background:var(--ink-2);margin-bottom:10px;font-size:14px;color:#cdd9e4;line-height:1.5;scroll-margin-top:80px}
ol.bib li::before{content:counter(b);position:absolute;left:14px;top:12px;color:var(--teal);font-weight:800;font-variant-numeric:tabular-nums}
ol.bib li b{color:#fff}
ol.bib a{color:var(--teal);word-break:break-word}
.tag{display:inline-block;font-size:10.5px;font-weight:700;letter-spacing:.04em;padding:2px 8px;border-radius:999px;margin-right:6px;vertical-align:middle;text-transform:uppercase}
.tag.peer{color:#86efac;background:rgba(74,222,128,.12);border:1px solid rgba(74,222,128,.4)}
.tag.org{color:#93c5fd;background:rgba(96,165,250,.12);border:1px solid rgba(96,165,250,.4)}
.tag.review{color:#f4c178;background:rgba(240,168,67,.12);border:1px solid rgba(240,168,67,.4)}
.tag.history{color:#d8b4fe;background:rgba(167,139,250,.12);border:1px solid rgba(167,139,250,.4)}
.tag.media{color:#cbd5e1;background:rgba(148,163,184,.14);border:1px solid rgba(148,163,184,.35)}
.tag.counter{color:#fca5a5;background:rgba(248,113,113,.12);border:1px solid rgba(248,113,113,.4)}

.bib-toggle{margin-top:8px}
.bib-toggle>summary{cursor:pointer;display:inline-block;padding:11px 18px;border:1px solid rgba(45,212,200,.4);border-radius:999px;color:var(--teal);font-weight:700;font-size:14px;list-style:none;-webkit-tap-highlight-color:transparent}
.bib-toggle>summary::-webkit-details-marker{display:none}
.bib-toggle>summary::after{content:" ▾";font-size:12px}
.bib-toggle[open]>summary{margin-bottom:16px}
.bib-toggle[open]>summary::after{content:" ▴"}

footer{border-top:1px solid var(--line);padding:32px 0 60px;color:var(--muted);font-size:13.5px;text-align:center}
footer a{color:var(--muted)}