:root{
  --bg:#0a0a0a;
  --bg-soft:#141414;
  --bg-card:#181818;
  --line:#262626;
  --fg:#ededed;
  --muted:#9a9a9a;
  --accent:#f7931a;        /* bitcoin orange */
  --accent-soft:#2a1d0a;
  --link:#ffb347;
  --max:960px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  background:var(--bg);
  color:var(--fg);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  line-height:1.55;
  -webkit-text-size-adjust:100%;
}
a{color:var(--link);text-decoration:underline;text-underline-offset:3px;text-decoration-color:rgba(255,179,71,.5)}
a:hover{text-decoration-color:var(--accent)}
.brand,.nav-links a,.btn,.footer-inner .links a,a.detail-btn{text-decoration:none}
img{max-width:100%;height:auto;display:block;border-radius:8px}

/* ---------- header / nav ---------- */
.site-header{
  position:sticky;top:0;z-index:50;
  background:rgba(10,10,10,.92);
  backdrop-filter:blur(8px);
  border-bottom:1px solid var(--line);
}
.nav-inner{
  max-width:var(--max);margin:0 auto;
  display:flex;align-items:center;justify-content:space-between;
  padding:.7rem 1rem;gap:1rem;
}
.brand{
  font-weight:800;letter-spacing:.18em;font-size:1.25rem;
  color:var(--accent);white-space:nowrap;
}
.brand:hover{text-decoration:none}
.nav-toggle{
  background:none;border:1px solid var(--line);color:var(--fg);
  font-size:1.4rem;line-height:1;padding:.25rem .55rem;border-radius:6px;cursor:pointer;
  display:none;
}
.nav-links{
  display:flex;flex-wrap:wrap;align-items:center;gap:.25rem .9rem;
  list-style:none;margin:0;padding:0;
}
.nav-links a{
  color:var(--fg);font-size:.82rem;letter-spacing:.03em;
  padding:.3rem .15rem;text-transform:uppercase;white-space:nowrap;
}
.nav-links a:hover,.nav-links a.active{color:var(--accent);text-decoration:none}
.nav-links .sub{font-size:.72rem;color:var(--muted)}

@media (max-width:860px){
  .nav-toggle{display:block}
  .nav-links{
    display:none;width:100%;flex-direction:column;align-items:stretch;
    gap:0;padding:.2rem 0 .4rem;
  }
  .nav-links.open{display:flex}
  .nav-links a{display:block;width:100%;padding:.42rem .2rem;font-size:.95rem;
    border-bottom:1px solid rgba(255,255,255,.04)}
  .nav-links a:last-child{border-bottom:none}
  .nav-links a:active{background:rgba(255,255,255,.03)}
  .nav-inner{flex-wrap:wrap}
}

/* ---------- layout ---------- */
main{max-width:var(--max);margin:0 auto;padding:1.4rem 1rem 3rem}
.page-title{
  font-size:1.6rem;letter-spacing:.08em;margin:.4rem 0 1.1rem;
  border-left:4px solid var(--accent);padding-left:.7rem;
}
.lead{color:var(--muted);margin-top:-.4rem}
hr{border:none;border-top:1px solid var(--line);margin:1.8rem 0}
section{margin:1.4rem 0}
h2{font-size:1.15rem;letter-spacing:.05em;margin:1.6rem 0 .6rem;color:var(--fg)}
h3{font-size:.95rem;letter-spacing:.06em;color:var(--accent);text-transform:uppercase;margin:1.2rem 0 .5rem}

/* code / address chips */
.mono{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}
.addr{
  display:inline-block;max-width:100%;background:var(--bg-soft);border:1px solid var(--line);
  border-radius:8px;padding:.5rem .7rem;white-space:nowrap;overflow-x:auto;
  font-size:clamp(.6rem,2.9vw,.82rem);
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;color:var(--accent);
}
.addr-copy{cursor:pointer;display:inline-flex;align-items:center;gap:.5rem;text-align:left}
.addr-copy:hover{border-color:var(--accent)}
.addr-copy:active{background:var(--accent-soft)}
.addr-copy .addr-ico{font-style:normal;color:var(--muted);flex:none}
.addr-copy.copied{border-color:var(--accent);color:#fff}
.addr-copy.copied .addr-ico{color:var(--accent)}

/* hero */
.shot{display:block;width:100%;max-width:480px;margin:0 auto;border-radius:8px}

/* animated intro */
.intro{max-width:600px;margin:1.2rem auto .4rem;text-align:center}
.intro-controls{display:flex;gap:.5rem;justify-content:center;margin-bottom:1rem;flex-wrap:wrap}
.intro-voice{background:var(--bg-soft);border:1px solid var(--line);color:var(--muted);
  border-radius:20px;padding:.4rem .9rem;font-size:.8rem;cursor:pointer;display:inline-flex;
  align-items:center;gap:.4rem}
.intro-voice[aria-pressed="true"]{border-color:var(--accent);color:var(--accent)}
.intro-stage{position:relative;min-height:5.2em;display:flex;align-items:center;justify-content:center}
.intro-line{position:absolute;left:0;right:0;margin:0;font-size:1.05rem;line-height:1.55;color:var(--fg);
  opacity:0;transform:translateX(40px);transition:opacity .45s ease,transform .45s ease;pointer-events:none}
.intro-line.in{opacity:1;transform:translateX(0)}
.intro-line.out{opacity:0;transform:translateX(-40px)}
.intro-line .w{transition:color .1s ease,background .1s ease;border-radius:3px;padding:0 1px}
.intro-line .w.hl{color:#000;background:var(--accent)}
.hero{text-align:center;margin:1rem 0 2rem}
.livestats{display:flex;flex-wrap:wrap;justify-content:center;gap:.4rem;margin:0 0 1.4rem}
.ls-item{background:var(--bg-card);border:1px solid var(--line);border-radius:8px;
  padding:.3rem .6rem;min-width:80px;text-align:center;flex:1 1 auto}
.ls-label{display:block;font-size:.6rem;letter-spacing:.05em;text-transform:uppercase;color:var(--muted)}
.ls-val{display:block;font-size:.85rem;font-weight:700;color:var(--accent);margin-top:.05rem}
.ls-val.up{color:#1fbf75}.ls-val.down{color:#e5484d}
.hero img{margin:0 auto;max-width:480px;width:100%}
.hero .tag{margin-top:1rem;color:var(--muted);letter-spacing:.2em;font-size:.9rem}

/* button-style link grid */
.btn-row{display:flex;flex-wrap:wrap;gap:.6rem;margin:1rem 0}
.btn{
  display:inline-block;background:var(--accent-soft);border:1px solid var(--accent);
  color:var(--accent);padding:.6rem 1rem;border-radius:8px;font-weight:600;
  font-size:.85rem;letter-spacing:.04em;
}
.btn:hover{background:var(--accent);color:#000;text-decoration:none}

/* link list cards */
.link-group{
  background:var(--bg-card);border:1px solid var(--line);border-radius:12px;
  padding:1rem 1.1rem;margin:1rem 0;
}
.link-group h3{margin-top:0}
.link-group ul{list-style:none;margin:.3rem 0 0;padding:0;
  display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:.3rem .9rem}
.link-group li{padding:.18rem 0;font-size:.9rem}
.link-group li a{color:var(--link);text-decoration:underline;text-underline-offset:3px;text-decoration-color:rgba(255,179,71,.45)}
.link-group li a:hover{color:#fff;text-decoration-color:var(--accent)}
.link-group li a::before{content:"\2192 ";color:var(--accent);text-decoration:none;font-weight:700}
.link-copy{background:transparent;border:1px solid var(--line);color:var(--accent);border-radius:6px;
  font-size:.85rem;line-height:1;padding:.12rem .35rem;margin-left:.35rem;cursor:pointer;vertical-align:middle}
.link-copy:hover{background:var(--accent);color:#0d1117}
.link-copy.copied{background:var(--accent);color:#0d1117;border-color:var(--accent)}

/* interest tick-boxes */
.pick{display:flex;align-items:center;gap:.5rem;width:100%;cursor:pointer;
  margin:.6rem 0 0;padding:.6rem .8rem;border:1px solid var(--line);border-radius:8px;
  background:var(--bg-soft);font-size:.9rem;box-sizing:border-box}
.pick:hover{border-color:var(--accent)}
.pick-cb{position:absolute;opacity:0;width:0;height:0}
.pick-box{width:18px;height:18px;border:2px solid var(--accent);border-radius:4px;flex:0 0 auto;
  display:inline-block;position:relative}
.pick-cb:checked + .pick-box{background:var(--accent)}
.pick-cb:checked + .pick-box::after{content:"";position:absolute;left:4px;top:0;width:5px;height:10px;
  border:solid #0d1117;border-width:0 2px 2px 0;transform:rotate(45deg)}
.pick-txt{flex:1 1 auto;color:var(--fg);font-weight:600}
.pick-cb:checked ~ .pick-txt{color:var(--accent)}
.pick-code{color:var(--muted);letter-spacing:.04em;font-weight:700;font-size:.8rem}
.pick-wrap{margin:0}
.pickrow{margin:.4rem 0}
.pick-note{font-size:.78rem;color:var(--muted);margin-left:.3rem}
.sendbox{background:var(--bg-card);border:1px solid var(--accent);border-radius:12px;padding:1rem 1.1rem;margin:1.4rem 0}
.picked-list{font-size:.85rem;color:var(--fg)}
.picked-list .pi{display:inline-block;background:var(--bg-soft);border:1px solid var(--line);border-radius:6px;
  padding:.1rem .4rem;margin:.15rem .2rem .15rem 0}
.picked-list .pc{color:var(--accent);font-weight:700}

/* image gallery */
.gallery{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:.8rem}
.figrow{display:grid;grid-template-columns:1fr;gap:.7rem;margin:1rem 0}
.figcard{background:var(--bg-soft);border:1px solid var(--line);border-radius:10px;padding:.8rem 1rem;display:flex;align-items:center;gap:1rem;text-align:left}
.figcard .ini{width:48px;height:48px;border-radius:50%;flex:0 0 48px;margin:0;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:1rem;color:#0d1117;background:var(--accent)}
.figcard .nm{font-weight:600;font-size:.95rem;margin:0}
.figcard .yr{color:var(--accent);font-weight:700;font-size:.82rem;margin:.1rem 0 0}
.quote{background:var(--bg-soft);border-left:3px solid var(--accent);border-radius:8px;padding:1rem 1.2rem;margin:1rem 0}
.quote p{font-size:1.05rem;line-height:1.55;font-style:italic;margin:0 0 .5rem;color:var(--fg)}
.quote .by{color:var(--accent);font-weight:600;font-style:normal;font-size:.9rem;margin:0}
.pagenav{display:flex;justify-content:space-between;align-items:center;gap:.6rem;margin:2rem 0 .5rem;padding-top:1.2rem;border-top:1px solid var(--line)}
.pagenav-btn{background:var(--bg-soft);border:1px solid var(--line);color:var(--accent);border-radius:8px;padding:.6rem .9rem;font-size:.9rem;font-weight:600;text-decoration:none;max-width:48%;line-height:1.2}
.pagenav-btn:hover{border-color:var(--accent);background:var(--accent);color:#0d1117}
.fade-in{opacity:0;transform:translateY(16px);transition:opacity .7s ease,transform .7s ease}
.fade-in.shown{opacity:1;transform:translateY(0)}
table.btmi{width:100%;border-collapse:collapse;margin:1rem 0;font-size:.9rem}
table.btmi th,table.btmi td{border:1px solid var(--line);padding:.5rem .6rem;text-align:right}
table.btmi th{background:var(--bg-soft);color:var(--accent);text-align:center;font-size:.82rem}
table.btmi td:first-child,table.btmi th:first-child{text-align:left}
.figcard .rl{color:var(--muted);font-size:.82rem;margin:.1rem 0 0;line-height:1.35}
.detail-btn{background:var(--bg-soft);border:1px solid var(--accent);color:var(--accent);border-radius:8px;padding:.45rem .8rem;font-size:.85rem;cursor:pointer;font-weight:600;margin:.3rem 0}
.detail-btn:hover{background:var(--accent);color:#0d1117}
.detail-panel{display:none;border:1px solid var(--line);border-radius:10px;padding:.9rem 1rem;margin:.5rem 0;background:var(--bg-soft)}
.detail-panel.open{display:block}
.detail-panel p{margin:.4rem 0;font-size:.9rem;line-height:1.5}

/* collapsible course blocks */
.detail{display:none}
.detail.open{display:block}
.course{padding:.7rem .9rem}
.course-head{display:flex;align-items:center;justify-content:space-between;width:100%;
  background:transparent;border:none;cursor:pointer;padding:0;text-align:left;color:var(--accent);
  font-family:inherit}
.course-title{font-size:.95rem;font-weight:700;letter-spacing:.02em;text-transform:uppercase;color:var(--accent)}
.course-chev{flex:0 0 auto;margin-left:.6rem;display:flex;flex-direction:column;align-items:center;justify-content:center;
  gap:.05rem;background:var(--accent);color:#0d1117;border-radius:8px;padding:.35rem .5rem;min-width:3.6rem;text-align:center;line-height:1.05}
.chev-txt{font-size:.6rem;letter-spacing:.03em;text-transform:uppercase;font-weight:700;display:block}
.course-arrow{display:block;font-size:.85rem;line-height:1;transition:transform .15s}
.course-head[aria-expanded="true"] .course-chev{background:transparent;color:var(--accent);border:1px solid var(--accent);padding:.3rem .45rem}
.course-head[aria-expanded="true"] .course-arrow{transform:rotate(180deg)}
.course-sum{color:var(--muted);font-size:.88rem;line-height:1.45;margin:.4rem 0 .2rem}
.course-detail{margin-top:.5rem}
.course-detail ul{margin:.2rem 0;padding-left:1.2rem}
/* tinyseed demo */
.ts-demo{margin:.8rem 0 0;border-top:1px solid var(--line);padding-top:.8rem}
.ts-warn{background:rgba(229,72,77,.08);border:1px solid #e5484d;border-radius:8px;padding:.6rem .8rem;font-size:.82rem;color:#f2b8ba;line-height:1.45;margin:0 0 .7rem}
.ts-readout{font-family:"Courier New",Courier,ui-monospace,monospace;font-size:.82rem;margin-top:.2rem}
.ts-line{display:grid;grid-template-columns:2rem 1fr 4.2rem 7.5rem;gap:.4rem;align-items:baseline;
  padding:.18rem 0;border-bottom:1px solid rgba(255,255,255,.04)}
.ts-n{color:var(--muted);text-align:right}
.ts-w{color:var(--fg);font-weight:700}
.ts-i{color:var(--muted);text-align:right}
.ts-b{color:var(--accent);letter-spacing:.06em;text-align:right;white-space:nowrap}
.ts-len-label{font-size:.82rem;color:var(--muted);margin:.2rem 0 .35rem}
.ts-len{display:flex;gap:.4rem;margin:0 0 .4rem}
.ts-len-btn{flex:1 1 auto;background:var(--bg-soft);border:1px solid var(--line);color:var(--fg);
  border-radius:8px;padding:.5rem 0;font-size:.9rem;font-weight:700;cursor:pointer;font-family:inherit}
.ts-len-btn.active{background:var(--accent);color:#0d1117;border-color:var(--accent)}
.ts-len-note{font-size:.76rem;color:var(--muted);margin:0 0 .7rem;line-height:1.4}
.ts-head{display:grid;grid-template-columns:2rem 1fr 4.2rem 7.5rem;gap:.4rem;align-items:baseline;
  font-family:"Courier New",Courier,ui-monospace,monospace;font-size:.78rem;font-weight:700;
  color:var(--accent);padding:.2rem 0;border-bottom:1px solid var(--line);margin-top:.6rem;text-transform:uppercase;letter-spacing:.04em}
.ts-head span{color:var(--accent)!important}
.ts-head .ts-n,.ts-head .ts-i,.ts-head .ts-b{text-align:right}
.gallery figure{margin:0}
.gallery img{width:100%;height:200px;object-fit:cover;border-radius:8px}
.gallery figcaption{font-size:.78rem;color:var(--muted);margin-top:.35rem;text-align:center}

/* steps */
.steps{background:var(--bg-card);border:1px solid var(--line);border-radius:12px;padding:1rem 1.2rem;margin:1rem 0}
.steps h3{margin-top:0}
.steps ol,.steps ul{margin:.4rem 0;padding-left:1.2rem}
.steps li{margin:.35rem 0;font-size:.92rem}

.note{
  background:var(--accent-soft);border:1px solid var(--accent);border-radius:10px;
  padding:.8rem 1rem;font-size:.86rem;color:var(--link);margin:1rem 0;
}
.disclaimer{font-size:.8rem;color:var(--muted);font-style:italic}

/* footer */
.site-footer{
  border-top:1px solid var(--line);background:var(--bg-soft);
  padding:1.4rem 1rem 2rem;margin-top:2rem;
}
.footer-inner{max-width:var(--max);margin:0 auto;text-align:center}
.footer-inner .links{
  display:flex;flex-wrap:wrap;justify-content:center;gap:.4rem 1rem;
  list-style:none;padding:0;margin:0 0 1rem;font-size:.8rem;
}
.footer-inner .links a{color:var(--muted);text-transform:uppercase;letter-spacing:.05em}
.footer-inner .links a:hover{color:var(--accent)}
.footer-inner .copy{color:var(--muted);font-size:.78rem}

/* course filter */
.coursefilter{background:var(--bg-soft);border:1px solid var(--line);border-radius:10px;padding:.9rem;margin:1.2rem 0}
.cf-search-row{display:flex;gap:.5rem;margin-bottom:.7rem}
.cf-search{flex:1;background:#0d1117;border:1px solid var(--line);color:#f5f6f8;border-radius:8px;padding:.6rem .8rem;font-size:.95rem}
.cf-search:focus{outline:none;border-color:var(--accent)}
.cf-clear{background:#0d1117;border:1px solid var(--line);color:var(--muted);border-radius:8px;padding:.6rem .9rem;font-size:.85rem;cursor:pointer;white-space:nowrap}
.cf-clear:hover{border-color:var(--accent);color:var(--accent)}
.cf-tags{display:flex;flex-wrap:wrap;gap:.4rem}
.cf-tag{background:#0d1117;border:1px solid var(--line);color:#cfcfcf;border-radius:999px;padding:.35rem .8rem;font-size:.82rem;cursor:pointer;transition:all .15s ease}
.cf-tag:hover{border-color:var(--accent);color:var(--accent)}
.cf-tag.on{background:var(--accent);border-color:var(--accent);color:#0d1117;font-weight:600}
.cf-count{margin:.7rem 0 0;color:var(--muted);font-size:.82rem;text-align:center}

/* home quick-jump chips */
.chip-row{display:flex;flex-wrap:wrap;gap:.4rem;justify-content:center;margin:1rem 0}
.chip{display:inline-block;background:var(--bg-soft);border:1px solid var(--line);color:#cfcfcf;border-radius:999px;padding:.32rem .7rem;font-size:.8rem;text-decoration:none;transition:all .15s ease;white-space:nowrap}
.chip:hover{border-color:var(--accent);color:var(--accent)}

/* footer chip nav */
.footer-chips{margin:0 0 1.1rem;padding-bottom:1rem;border-bottom:1px solid var(--line)}
.chip.chip-here{background:var(--accent);border-color:var(--accent);color:#0d1117;font-weight:600}

/* disabled send button until a class is ticked */
.send-interests.is-disabled{opacity:.4;filter:grayscale(0.6);cursor:not-allowed;pointer-events:none}

/* visually hidden (SEO/screen-reader heading, not shown) */
.visually-hidden{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}

/* multipage */
.page{display:block}