@import url('https://fonts.googleapis.com/css2?family=Poppins:ital,wght@0,400;0,500;0,600;0,700;0,800;1,400;1,600&family=Inter:opsz,wght@14..32,300..700&family=JetBrains+Mono:wght@400;500&family=Dancing+Script:wght@500;600&display=swap');

/* ============ Quantix Invest design system: "The Vault"
   paper cream + pine ink + restrained gold. Editorial serif display,
   hairline rules, deliberate whitespace. ============ */
:root{
  --paper:#FBF6EA;--paper-2:#F3ECD9;--card:#FDF9F0;
  --ink:#241C15;--ink-soft:#453B31;--muted:#776C60;
  --pine:#B01E28;--pine-deep:#1B1510;--pine-bright:#D22F3A;
  --gold:#B08A3E;--gold-soft:#D4B36A;--cursive:"Dancing Script",cursive;
  --line:#E4DBC6;--line-strong:#C6BBA0;--line-dark:rgba(251,246,234,.18);
  --maxw:1180px;--radius:10px;
  --shadow:0 1px 2px rgba(36,28,21,.06);
  --shadow-lift:0 14px 40px -18px rgba(36,28,21,.2);
  --serif:"Poppins",Inter,sans-serif;
  --sans:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
  --mono:"JetBrains Mono",ui-monospace,SFMono-Regular,monospace;
}
*{box-sizing:border-box}
::selection{background:var(--pine);color:var(--paper)}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important;animation:none!important}}
body{margin:0;font-family:var(--sans);background:var(--paper);color:var(--ink);
  line-height:1.72;font-size:16.5px;font-optical-sizing:auto;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:var(--pine);text-decoration:none}
a:hover{color:var(--pine-bright)}
article a,p a:not(.btn),li a,dd a{text-decoration:underline;text-decoration-color:var(--line-strong);
  text-underline-offset:3px;text-decoration-thickness:1px;transition:text-decoration-color .18s}
article a:hover,p a:not(.btn):hover,li a:hover,dd a:hover{text-decoration-color:var(--gold)}
:focus-visible{outline:2px solid var(--gold);outline-offset:3px;border-radius:2px}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 28px}

/* ---------- header: hairline bar on paper ---------- */
body::after{content:"";position:fixed;top:0;left:0;right:0;height:3px;z-index:70;
  background:linear-gradient(90deg,var(--pine),var(--gold-soft))}
header.site{position:sticky;top:0;z-index:60;background:color-mix(in srgb,var(--paper) 92%,transparent);
  backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
header.site a{text-decoration:none}
header.site .wrap{display:flex;align-items:center;gap:20px;height:68px}
.logo{font-family:var(--serif);font-weight:700;font-size:19px;color:var(--ink);
  letter-spacing:-.01em;display:flex;align-items:center;gap:11px}
.logo:hover{color:var(--ink)}
.logo .qmark{flex:none;display:block}
.logo span{color:var(--pine)}
nav.main{display:flex;gap:4px;margin-left:auto;font-size:14px;align-items:center;font-family:var(--serif)}
nav.main a{color:var(--ink-soft);font-weight:500;padding:8px 11px;border-radius:6px;
  transition:color .16s;position:relative;white-space:nowrap;font-size:13.5px}
nav.main a:hover{color:var(--pine);background:none}
nav.main a:hover::after{content:"";position:absolute;left:12px;right:12px;bottom:2px;height:2px;background:var(--gold-soft);border-radius:2px}
nav.main a.active{color:var(--pine);font-weight:600}
nav.main a.active::after{content:"";position:absolute;left:13px;right:13px;bottom:2px;height:2px;background:var(--gold);border-radius:2px}
nav.main a i{font-style:normal;font-size:10px;background:none;border:1px solid var(--gold-soft);border-radius:4px;
  padding:1px 5px;margin-left:6px;letter-spacing:.05em;color:var(--gold);vertical-align:1px;font-family:var(--sans)}
nav.main a.cta{background:var(--pine);color:#FBF6EA;border-radius:6px;font-weight:600;margin-left:6px}
nav.main a.cta:hover{background:#8E1620;color:#FBF6EA}
nav.main a.cta.active::after{content:none}
nav.main a.cta:hover::after{content:none}
nav.main a.ghost-nav{border:1.5px solid var(--gold-soft);color:var(--gold);border-radius:6px;font-weight:600;margin-left:2px}
nav.main a.ghost-nav:hover{border-color:var(--gold);color:var(--gold)}
nav.main a.ghost-nav:hover::after,nav.main a.ghost-nav.active::after{content:none}

/* ---------- hero ---------- */
.hero{position:relative;padding:76px 0 68px;border-bottom:1px solid var(--line)}
.hero::before{content:none}
.hero .wrap{position:relative}
h1{font-family:var(--serif);font-size:clamp(38px,5.2vw,66px);line-height:1.03;margin:0 0 22px;
  font-weight:700;letter-spacing:-.01em;text-transform:uppercase}
h1 em,.serif-i{font-style:normal;font-weight:700;color:var(--pine)}
.sub{color:var(--ink-soft);font-size:19px;max-width:640px;line-height:1.65;margin:0;font-weight:400}
.hero .wrap:not(.hero-split){text-align:center}
.hero .wrap:not(.hero-split) .sub{margin:0 auto 8px}
.hero p:has(.btn){display:flex;gap:14px;flex-wrap:wrap;margin-top:30px}
.hero .wrap:not(.hero-split) p:has(.btn){justify-content:center}
.hero-split{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,.95fr);gap:64px;align-items:center;text-align:left}
.hero-split .sub{margin:0 0 8px}
.hero-art{display:flex;flex-direction:column;gap:18px;justify-content:center}
.hero-art .photo{width:100%}

/* kicker: small caps over a short gold rule */
.kicker{display:block;font-size:12px;font-weight:600;text-transform:uppercase;
  letter-spacing:.22em;color:var(--gold);margin-bottom:18px}
.kicker::before{content:"";display:block;width:34px;height:2px;background:var(--gold);margin-bottom:14px}
article .kicker{margin-bottom:14px}

/* trust row: understated */
.trust{display:flex;gap:26px;flex-wrap:wrap;margin:30px 0 0;padding:0;list-style:none}
.trust li,.trust .pill{display:inline-flex;align-items:center;gap:9px;background:none;border:none;
  padding:0;font-size:13.5px;font-weight:500;color:var(--muted);letter-spacing:.01em}
.trust .dot{width:5px;height:5px;border-radius:50%;background:var(--gold);display:inline-block}

/* dark hero band */
.hero.dark{background:var(--pine-deep);border-bottom:none;color:var(--paper)}
.hero.dark::before{background:radial-gradient(760px 420px at 88% -10%,rgba(200,165,92,.16),transparent 70%)}
.hero.dark h1{color:var(--paper)}
.hero.dark h1 em{color:var(--gold-soft)}
.hero.dark .sub{color:color-mix(in srgb,var(--paper) 74%,transparent)}
.hero.dark .kicker{color:var(--gold-soft)}
.hero.dark .kicker::before{background:var(--gold-soft)}
.hero.dark .trust li{color:color-mix(in srgb,var(--paper) 62%,transparent)}
.hero.dark .trust .dot{background:var(--gold-soft)}
.hero.dark .btn{background:var(--gold-soft);border-color:var(--gold-soft);color:var(--pine-deep);font-weight:600}
.hero.dark .btn:hover{background:#D9BC7E;border-color:#D9BC7E}
.hero.dark .btn.ghost{background:transparent;color:var(--paper);border-color:var(--line-dark)}
.hero.dark .btn.ghost:hover{border-color:var(--paper);color:var(--paper)}
.hero.dark .photo{background:rgba(250,248,243,.06);border-color:var(--line-dark);box-shadow:none}
.hero.dark .photo figcaption{color:color-mix(in srgb,var(--paper) 55%,transparent)}
.hero.dark .scribble{color:var(--gold-soft);border-color:var(--gold-soft)}

/* ---------- type & rhythm ---------- */
h2{font-family:var(--serif);font-size:clamp(26px,3vw,38px);margin:60px 0 16px;font-weight:700;
  letter-spacing:-.012em;line-height:1.12}
h3{font-family:var(--serif);font-size:20px;margin:38px 0 10px;font-weight:600;letter-spacing:-.008em}
main{padding:44px 0 88px}
section.wrap{margin-bottom:8px}
hr.squiggle{border:none;height:1px;margin:60px auto;max-width:var(--maxw);background:var(--line)}

/* ---------- cards: hairline, ink on hover ---------- */
.grid{display:grid;gap:20px;background:none;border:none}
.grid.c3{grid-template-columns:repeat(3,1fr)}
.grid.c2{grid-template-columns:repeat(2,1fr)}
.grid .card{border:1.5px solid var(--ink);border-radius:8px}
.card{background:var(--card);border:1.5px solid var(--ink);border-radius:8px;padding:30px;
  min-width:0;overflow-wrap:break-word;transition:transform .18s,box-shadow .18s;position:relative}
.card:hover{transform:translate(-2px,-2px);box-shadow:4px 4px 0 var(--ink)}
.card h2{margin:6px 0 12px}
.card h3{margin:6px 0 10px;font-size:19.5px}
.card h3 a{color:var(--ink);text-decoration:none}
.card h3 a::after{content:"";position:absolute;inset:0}
.card h3 a:hover{color:var(--pine)}
.card p{color:var(--muted);margin:0;font-size:15px;line-height:1.62}
.card ol{margin:14px 0 0;padding-left:20px;font-size:15px}
.card ol li{margin:6px 0}
.card ol a,.card p a{position:static;text-decoration:none}
.card ol a:hover{text-decoration:underline;text-decoration-color:var(--gold)}
.photo-top{margin:-30px -30px 18px;overflow:hidden;border-bottom:1.5px solid var(--ink);border-radius:6px 6px 0 0}
.photo-top img{width:100%;height:170px;object-fit:cover;display:block;
  filter:saturate(.82) contrast(1.02);transition:filter .3s}
.card:hover .photo-top img{filter:saturate(1) contrast(1.02)}

/* ---------- buttons ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;background:var(--pine);
  color:#FBF6EA;font-weight:600;padding:15px 30px;border-radius:5px;border:1.5px solid var(--ink);
  cursor:pointer;font-size:15px;letter-spacing:.01em;font-family:var(--serif);
  transition:transform .15s,box-shadow .15s}
.btn::after{content:"→";font-family:var(--sans);transition:transform .18s}
.btn:hover{transform:translate(-2px,-2px);box-shadow:4px 4px 0 var(--ink);color:#FBF6EA;text-decoration:none}
.btn:hover::after{transform:translateX(3px)}
.btn.ghost{background:transparent;color:var(--ink);border:1.5px solid var(--ink)}
.btn.ghost::after{content:none}
.btn.ghost:hover{background:var(--paper-2);color:var(--ink)}

/* ---------- stats: ledger style ---------- */
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:0;margin:30px 0;
  border-top:2px solid var(--gold)}
.stats .stat{background:none;border:none;border-top:none;padding:22px 24px 0 0;text-align:left}
.stat .n{font-family:var(--serif);font-size:42px;font-weight:700;letter-spacing:-.02em;color:var(--ink);
  font-variant-numeric:tabular-nums}
.stat .l{color:var(--muted);font-size:13px;font-weight:500;margin-top:6px;text-transform:uppercase;letter-spacing:.08em}

/* ---------- steps ---------- */
.steps{counter-reset:step}
.steps .card::before{counter-increment:step;content:"0" counter(step);
  font-family:var(--serif);font-weight:800;font-size:34px;color:var(--pine);
  display:block;line-height:1;margin-bottom:14px}

/* ---------- article ---------- */
article{max-width:720px;margin:0 auto}
article p,article li{color:var(--ink-soft);font-size:17px;line-height:1.78}
article>p:first-of-type{font-size:19px;color:var(--ink)}
article h1{font-size:clamp(32px,4.2vw,48px);text-transform:none;letter-spacing:-.015em}
article h2{font-size:clamp(26px,3vw,34px);margin:56px 0 14px}
blockquote{font-family:var(--serif);font-style:normal;font-weight:500;font-size:18px;color:var(--ink-soft);
  border-left:2px solid var(--gold);margin:32px 0;padding:4px 0 4px 26px;background:none;line-height:1.6}
table{border-collapse:collapse;width:100%;margin:26px 0;font-size:14.5px;background:var(--card);
  border:1px solid var(--line)}
th,td{border-bottom:1px solid var(--line);padding:12px 16px;text-align:left}
tr:last-child td{border-bottom:none}
th{background:var(--paper-2);font-weight:600;font-size:12px;text-transform:uppercase;
  letter-spacing:.09em;color:var(--muted);font-family:var(--sans)}
td{font-variant-numeric:tabular-nums}
tbody tr:hover{background:#FFFDF8}
code{font-family:var(--mono);background:var(--paper-2);border:1px solid var(--line);
  padding:2px 7px;border-radius:5px;font-size:.85em}

/* ---------- callouts: ledger notes ---------- */
.callout{background:var(--card);border:1px solid var(--line);border-left:3px solid var(--gold);
  border-radius:0 var(--radius) var(--radius) 0;padding:20px 26px;margin:32px 0}
.callout.tip{border-left-color:var(--pine-bright)}
.callout.warn{border-left-color:#9C6B12}
.callout b:first-child,.callout strong:first-child{display:block;margin-bottom:6px;font-size:11.5px;
  text-transform:uppercase;letter-spacing:.16em;color:var(--muted);font-family:var(--sans)}

/* ---------- toc ---------- */
.toc{background:none;border:none;border-top:2px solid var(--gold);border-bottom:1px solid var(--line);
  border-radius:0;padding:20px 2px 22px;margin:36px 0;font-size:14.5px}
.toc b{display:block;margin-bottom:12px;font-size:11.5px;text-transform:uppercase;letter-spacing:.18em;color:var(--gold)}
.toc ol{margin:0;padding-left:18px;columns:2;column-gap:44px}
.toc li{margin:5px 0;break-inside:avoid}
.toc a{color:var(--ink-soft);text-decoration:none}
.toc a:hover{color:var(--pine);text-decoration:underline;text-decoration-color:var(--gold)}
.toc>a{display:block;margin:6px 0;padding-left:0;position:relative;color:var(--ink-soft);text-decoration:none}
.toc>a::before{content:"—";color:var(--line-strong);margin-right:10px}
.toc>a:hover{color:var(--pine)}

/* ---------- meta / pills ---------- */
.meta{color:var(--muted);font-size:13px;margin:20px 0 30px;display:flex;gap:18px;flex-wrap:wrap;align-items:center}
.pill{display:inline-flex;align-items:center;background:none;border:none;padding:0;font-size:12.5px;
  font-weight:550;color:var(--muted);text-transform:uppercase;letter-spacing:.1em}
.pill+.pill::before{content:"·";margin-right:18px;color:var(--line-strong)}

/* ---------- next/prev ---------- */
.next{display:flex;justify-content:space-between;gap:1px;margin-top:72px;font-weight:500;font-size:15px;
  border:1px solid var(--line);background:var(--line)}
.next a{padding:20px 24px;color:var(--ink);flex:1;min-width:0;overflow-wrap:break-word;background:var(--card);
  text-decoration:none;transition:background .18s,color .18s}
.next a:last-child{text-align:right}
.next a:hover{background:#FFFDF8;color:var(--pine)}

/* ---------- footer: dark pine band ---------- */
footer.site{border-top:none;margin-top:40px;padding:64px 0 48px;color:var(--line-strong);
  font-size:14px;background:var(--pine-deep)}
footer.site a{color:var(--gold-soft);text-decoration:none}
footer.site a:hover{color:var(--paper);text-decoration:underline}
footer.site .wrap{color:color-mix(in srgb,var(--paper) 78%,transparent)}
.disclaimer{font-size:12.5px;color:color-mix(in srgb,var(--paper) 45%,transparent);
  border-top:1px solid var(--line-dark);margin-top:26px;padding-top:20px;max-width:860px;line-height:1.65}

/* ---------- forms / calculators ---------- */
input,select{background:var(--card);color:var(--ink);border:1px solid var(--line-strong);border-radius:7px;
  padding:12px 15px;font-size:15.5px;width:100%;font-family:var(--sans);
  transition:border-color .15s,box-shadow .15s;outline:none}
input:focus,select:focus{border-color:var(--pine);box-shadow:0 0 0 3px color-mix(in srgb,var(--pine) 14%,transparent)}
label{font-weight:550;font-size:12.5px;display:block;margin:16px 0 7px;color:var(--muted);
  text-transform:uppercase;letter-spacing:.08em}
.result{font-family:var(--mono);font-size:24px;font-weight:500;margin:18px 0 4px;color:var(--pine);
  font-variant-numeric:tabular-nums}

.card .btn{margin-top:20px}
.card .result{margin-top:20px}
.callout h2{margin:4px 0 12px}
.callout h3{margin:4px 0 8px}

/* scroll-in reveal (JS adds .rv, then .in when visible) */
.rv{opacity:0;transform:translateY(16px);transition:opacity .55s ease,transform .55s cubic-bezier(.2,.7,.3,1)}
.rv.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.rv{opacity:1;transform:none;transition:none}}

/* article hero image */
.article-hero{margin:6px 0 26px;width:100%}
.article-hero img{aspect-ratio:21/9}

/* ---------- glossary ---------- */
dl.gloss dt{font-family:var(--serif);font-weight:600;text-transform:none;margin-top:26px;font-size:18px;letter-spacing:-.005em}
dl.gloss dd{margin:5px 0 0;color:var(--muted);font-size:15.5px}
#q{max-width:440px;margin:10px 0 8px}

/* ---------- photos ---------- */
.photo{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  padding:10px 10px 12px;box-shadow:var(--shadow);display:inline-block;max-width:100%}
.photo img{display:block;width:100%;border-radius:calc(var(--radius) - 4px);aspect-ratio:4/3;object-fit:cover;
  filter:saturate(.85)}
.photo figcaption{font-size:12.5px;color:var(--muted);text-align:center;padding-top:10px;letter-spacing:.02em}
figure.photo{margin:0}
.photo.tilt-l,.photo.tilt-r{rotate:none}

/* ---------- accents ---------- */
.hand,.note{font-family:var(--cursive);font-style:normal;font-size:19px;color:var(--muted);display:inline-block;line-height:1.4}
.photo figcaption{font-family:var(--cursive);font-size:16px}
blockquote.pull{font-family:var(--cursive);font-size:clamp(26px,3vw,38px);line-height:1.35;color:var(--ink);
  border:none;padding:0;margin:10px 0 6px;text-align:center}
blockquote.pull footer{font-family:var(--sans);font-size:12.5px;text-transform:uppercase;letter-spacing:.16em;color:var(--gold);margin-top:14px}
.note.blue{color:var(--pine)}
.scribble{position:relative;display:inline-block;color:var(--pine);border:2px solid var(--pine);padding:.04em .18em .08em;margin:.06em .05em;line-height:1.16;
  background-image:radial-gradient(circle,var(--pine) 3.2px,transparent 3.6px),radial-gradient(circle,var(--pine) 3.2px,transparent 3.6px),radial-gradient(circle,var(--pine) 3.2px,transparent 3.6px),radial-gradient(circle,var(--pine) 3.2px,transparent 3.6px);
  background-repeat:no-repeat;background-size:9px 9px;
  background-position:top -4.5px left -4.5px,top -4.5px right -4.5px,bottom -4.5px left -4.5px,bottom -4.5px right -4.5px}
.scribble>svg{display:none}
.hl{background:linear-gradient(180deg,transparent 55%,color-mix(in srgb,var(--gold-soft) 38%,transparent) 55%);
  padding:0 2px}
.doodle-arrow{stroke:var(--muted);stroke-width:2;fill:none;stroke-linecap:round}
.progress{position:fixed;top:0;left:0;height:2px;background:var(--gold);z-index:100;width:0}
.chart{margin:30px 0}
.chart .card{padding:20px 20px 16px;border:1px solid var(--line-strong)}
.chart .card:hover{transform:none;box-shadow:none}

/* ---------- show the math ---------- */
details.math{background:var(--paper-2);border:1px solid var(--line);border-radius:10px;margin:24px 0;padding:0}
details.math summary{cursor:pointer;font-family:var(--serif);font-weight:600;font-size:14px;padding:14px 20px;
  color:var(--pine);list-style:none;display:flex;align-items:center;gap:10px}
details.math summary::before{content:"\2211";font-family:var(--mono);font-size:15px;color:var(--gold)}
details.math summary::after{content:"+";margin-left:auto;font-family:var(--mono);color:var(--muted)}
details.math[open] summary::after{content:"\2212"}
details.math>*:not(summary){margin-left:20px;margin-right:20px}
details.math>p:last-child,details.math>table:last-child{margin-bottom:18px}
details.math code{background:#fff}

/* ---------- table scroll ---------- */
.table-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch;margin:26px 0}
.table-scroll table{margin:0;min-width:520px}
img{max-width:100%}

/* ---------- responsive ---------- */
@media(max-width:1120px){
  nav.main{overflow-x:auto;scrollbar-width:none;-webkit-overflow-scrolling:touch;min-width:0}
  nav.main::-webkit-scrollbar{display:none}
  nav.main a{white-space:nowrap;padding:8px 10px;font-size:13.5px}
  header.site .wrap{min-width:0}
}
@media(max-width:960px){
  .hero-split{grid-template-columns:1fr;gap:36px}
  .grid.c3{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:720px){
  body{font-size:16px}
  header.site .wrap{height:58px;gap:10px}
  .logo{font-size:18px}
  .hero{padding:60px 0 48px}
  h2{margin:56px 0 14px}
  main{padding:36px 0 80px}
  .card{padding:24px}
  .photo-top{margin:-24px -24px 16px}
  .btn{width:100%;padding:14px 22px}
  p:has(.btn){flex-direction:column;align-items:stretch}
  .trust{gap:14px}
  .toc ol{columns:1}
  .next{flex-direction:column}
  .next a:last-child{text-align:left}
  table{font-size:13.5px;display:block;overflow-x:auto;-webkit-overflow-scrolling:touch}
  th,td{padding:10px 12px}
  .result{overflow-wrap:anywhere}
  .stats{grid-template-columns:repeat(2,1fr)}
  .stat .n{font-size:34px}
  article p,article li{font-size:16px}
  hr.squiggle{margin:52px auto}
}
@media(max-width:640px){
  .grid.c3,.grid.c2{grid-template-columns:1fr}
}
@media(max-width:420px){
  h1{font-size:34px}
}

/* ---------- show-the-math boxes ---------- */
details.math{background:var(--card);border:1px solid var(--line);border-left:3px solid var(--gold);
  border-radius:8px;padding:14px 18px;margin:22px 0}
details.math summary{cursor:pointer;font-weight:600;color:var(--gold)}
details.math[open] summary{margin-bottom:10px}