/* LOAD Endurance: shared stylesheet for /learn/ pages */
:root{
  --carbon:#15181C; --carbon-2:#1E2227; --chalk:#F5F3EE; --paper:#FBFAF7;
  --forge:#D0432B; --forge-ink:#B5361F; --sulphur:#E4FF38; --grit:#D9D4CA;
  --ink:#15181C; --ink-2:#4A4E55; --ink-3:#6E7279; --line:#E3DED4;
  --display:"Archivo",system-ui,sans-serif; --body:"Spline Sans",system-ui,sans-serif;
  --mono:"Spline Sans Mono",ui-monospace,monospace;
  --measure:68ch; --gutter:clamp(16px,4vw,40px);
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--chalk);color:var(--ink);font:400 1.0625rem/1.65 var(--body);-webkit-font-smoothing:antialiased}
a{color:var(--forge-ink);text-underline-offset:.18em;text-decoration-thickness:1px}
a:hover{text-decoration-thickness:2px}
:focus-visible{outline:2px solid var(--forge);outline-offset:3px;border-radius:2px}
.skip{position:absolute;left:-9999px}.skip:focus{left:16px;top:12px;background:var(--chalk);padding:8px 12px;z-index:10}

/* Header: matches site; Learn is the active verb */
.site-head{background:var(--carbon);color:var(--chalk)}
.site-head .in{max-width:1180px;margin:0 auto;padding:14px var(--gutter);display:flex;align-items:center;gap:24px}
.brand{display:inline-flex;align-items:center;text-decoration:none;line-height:0;flex:none}
.brand .logo{display:block;height:28px;width:auto}
.brand .mark{display:none;width:30px;height:30px}
.nav{display:flex;gap:22px;margin-left:auto;align-items:center;font-size:.95rem}
.nav a{white-space:nowrap}
.nav a{color:var(--grit);text-decoration:none}
.nav a:hover,.nav a[aria-current]{color:var(--chalk)}
.nav a[aria-current]{box-shadow:inset 0 -2px 0 var(--forge);padding-bottom:4px}
.nav .cta{background:var(--forge);color:var(--chalk);padding:8px 14px;border-radius:4px;font-weight:600;transition:background-color .18s ease,transform .18s ease,box-shadow .18s ease}
.nav .cta:hover{transform:translateY(-1px);box-shadow:0 0 0 1px rgba(208,67,43,.6),0 0 14px 2px rgba(208,67,43,.55),0 0 32px 6px rgba(208,67,43,.25)}
.nav .cta:active{transform:none;box-shadow:none}
@media (prefers-reduced-motion:reduce){.nav .cta{transition:none}.nav .cta:hover{transform:none}}
@media (max-width:559px){.nav .hide-s{display:none}.nav{gap:16px}.site-head .in{gap:16px}}
@media (max-width:479px){
  .site-head .in{gap:10px;padding-left:16px;padding-right:16px}
  .brand .logo{display:none}
  .brand .mark{display:block}
  .nav{gap:12px;font-size:.875rem}
  .nav .cta{padding:8px 10px}
}
@media (max-width:359px){.site-head .in{gap:8px}.nav{gap:9px;font-size:.84rem}.nav .cta{padding:7px 8px}}

/* Page frame: article + sticky contents rail on wide screens */
.frame{max-width:1180px;margin:0 auto;padding:0 var(--gutter);display:grid;grid-template-columns:minmax(0,1fr);gap:48px}
@media (min-width:1040px){.frame{grid-template-columns:minmax(0,var(--measure)) 240px;justify-content:space-between}}
article{min-width:0;padding:28px 0 72px}

.crumbs{font-size:.875rem;color:var(--ink-3);margin:0 0 28px}
.crumbs ol{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:6px}
.crumbs li+li::before{content:"/";margin-right:6px;color:var(--grit)}
.crumbs a{color:var(--ink-3);text-decoration:none}.crumbs a:hover{color:var(--ink)}

.eyebrow{font:600 .8125rem/1 var(--display);letter-spacing:.12em;text-transform:uppercase;color:var(--forge-ink);margin:0 0 14px}
h1{font:800 clamp(2.1rem,5.5vw,3.25rem)/1.04 var(--display);letter-spacing:-.02em;margin:0 0 24px}
h2{font:700 1.6rem/1.2 var(--display);letter-spacing:-.01em;margin:56px 0 14px;scroll-margin-top:24px}
h3{font:700 1.15rem/1.3 var(--display);margin:32px 0 8px}
p,ul,ol{margin:0 0 18px}
li{margin-bottom:6px}
strong{font-weight:600}

/* The answer: the quotable block. Two sentences, no links, no jargon left undefined. */
.answer{background:var(--carbon);color:var(--chalk);border-radius:14px;padding:24px 26px;margin:0 0 22px;font-size:1.15rem;line-height:1.55}
.answer p{margin:0}.answer p+p{margin-top:10px;color:var(--grit);font-size:1rem}
.answer dfn{font-style:normal;font-weight:600;color:var(--chalk)}

.byline{display:flex;flex-wrap:wrap;gap:6px 18px;font-size:.9rem;color:var(--ink-3);padding:0 0 26px;border-bottom:1px solid var(--line);margin-bottom:30px}
.byline a{color:var(--ink-2);font-weight:500}

/* At a glance */
.glance{width:100%;border-collapse:collapse;font-size:.95rem;margin:0 0 8px}
.glance th,.glance td{text-align:left;vertical-align:top;padding:12px 12px 12px 0;border-bottom:1px solid var(--line)}
.glance thead th{font:600 .75rem/1 var(--display);letter-spacing:.1em;text-transform:uppercase;color:var(--ink-3)}
.glance tbody th{font:700 1rem/1.3 var(--display)}
.glance .aka{display:block;font:400 .8rem/1.4 var(--mono);color:var(--ink-3);margin-top:3px}
.scroll{overflow-x:auto;-webkit-overflow-scrolling:touch}

/* Formula */
.formula{background:var(--paper);border:1px solid var(--line);border-left:3px solid var(--forge);border-radius:8px;padding:18px 20px;font:500 .95rem/1.8 var(--mono);margin:0 0 18px;overflow-x:auto;white-space:pre}

/* Worked example */
.example{background:var(--carbon);color:var(--chalk);border-radius:14px;padding:22px 24px;margin:0 0 18px}
.example h3{margin:0 0 6px;color:var(--chalk)}
.example p{color:var(--grit);font-size:.95rem}
.example table{width:100%;border-collapse:collapse;font:400 .9rem/1.4 var(--mono)}
.example td,.example th{padding:9px 8px 9px 0;border-bottom:1px solid #2C3137;text-align:left}
.example th{font:600 .72rem/1 var(--display);letter-spacing:.1em;text-transform:uppercase;color:#9EA2A8}
.example .num{text-align:right}
.example .hl{color:var(--sulphur);font-weight:500}

/* Figure */
figure{margin:8px 0 22px}
.chart{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:12px 8px 4px}
.chart svg{display:block;width:100%;height:auto}
.chart .g{stroke:var(--line);stroke-width:1}.chart .g0{stroke:#B9B3A7;stroke-width:1}
.chart .ax{font:400 11px var(--mono);fill:var(--ink-3)}
.chart .fit{stroke:var(--carbon);stroke-width:2.5;fill:none}
.chart .fat{stroke:var(--forge);stroke-width:1.5;fill:none;opacity:.85}
.chart .frm{stroke:#6E7279;stroke-width:2;fill:none;stroke-dasharray:5 4}
.key{display:flex;flex-wrap:wrap;gap:16px;font-size:.85rem;color:var(--ink-2);padding:6px 10px 8px}
.key i{display:inline-block;width:18px;height:0;border-top:3px solid;vertical-align:middle;margin-right:6px}
figcaption{font-size:.875rem;color:var(--ink-3);margin-top:10px}

/* Callouts */
.note{border-left:3px solid var(--grit);padding:2px 0 2px 16px;color:var(--ink-2);margin:0 0 18px}
.note strong{color:var(--ink)}

/* FAQ */
.faq details{border-bottom:1px solid var(--line);padding:14px 0}
.faq summary{cursor:pointer;font:700 1.05rem/1.4 var(--display);list-style:none;display:flex;justify-content:space-between;gap:16px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-weight:400;color:var(--forge);font-size:1.3rem;line-height:1}
.faq details[open] summary::after{content:"–"}
.faq details p{margin:10px 0 0;color:var(--ink-2)}

/* Related */
.related{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:12px;list-style:none;padding:0}
.related a{display:block;height:100%;background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:14px 16px;text-decoration:none;color:var(--ink)}
.related a:hover{border-color:var(--ink-3)}
.related b{display:block;font:700 1rem/1.3 var(--display);margin-bottom:4px}
.related span{font-size:.875rem;color:var(--ink-3)}

/* In LOAD: one quiet paragraph, never a sales block */
.inload{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:20px 22px;margin-top:48px}
.inload .eyebrow{margin-bottom:8px}
.inload p{margin:0 0 10px;color:var(--ink-2)}.inload p:last-child{margin:0}

/* Sources */
.sources{font-size:.9rem;color:var(--ink-2);padding-left:20px}
.sources li{margin-bottom:10px}
.sources cite{font-style:italic}

/* Contents rail */
.toc{display:none}
@media (min-width:1040px){
  .toc{display:block;position:sticky;top:24px;align-self:start;margin-top:150px;font-size:.875rem}
  .toc p{font:600 .72rem/1 var(--display);letter-spacing:.12em;text-transform:uppercase;color:var(--ink-3);margin:0 0 12px}
  .toc ol{list-style:none;margin:0;padding:0;border-left:1px solid var(--line)}
  .toc li{margin:0}
  .toc a{display:block;padding:5px 0 5px 14px;color:var(--ink-2);text-decoration:none;margin-left:-1px;border-left:2px solid transparent}
  .toc a:hover{color:var(--ink);border-left-color:var(--grit)}
}

.site-foot{background:var(--carbon);color:var(--grit);font-size:.9rem}
.site-foot .in{max-width:1180px;margin:0 auto;padding:28px var(--gutter);display:flex;flex-wrap:wrap;gap:12px 22px;align-items:center}
.site-foot a{color:var(--grit);text-decoration:none}.site-foot a:hover{color:var(--chalk)}
.site-foot .c{margin-left:auto}

/* Template guide: add ?template to the URL to label every block. Invisible to visitors and crawlers. */
.guide [data-block]{position:relative;outline:1px dashed var(--forge);outline-offset:6px}
.guide [data-block]::before{content:attr(data-block);position:absolute;top:-22px;left:0;font:500 10px/1 var(--mono);background:var(--forge);color:#fff;padding:3px 6px;border-radius:3px;z-index:2;white-space:nowrap}

@media print{.site-head,.site-foot,.toc,.inload{display:none}.answer,.example{background:none;color:var(--ink);border:1px solid var(--ink)}}

/* End-of-page invite */
.endcta{margin-top:56px;padding:28px 26px;background:var(--carbon);color:var(--chalk);border-radius:14px}
.endcta h2{margin:0 0 8px;color:var(--chalk);font-size:1.35rem}
.endcta p{margin:0 0 18px;color:var(--grit)}
.btn{display:inline-block;background:var(--forge);color:var(--chalk);padding:11px 18px;border-radius:4px;font-weight:600;text-decoration:none;transition:transform .18s ease,box-shadow .18s ease}
.btn:hover{color:var(--chalk);transform:translateY(-1px);box-shadow:0 0 0 1px rgba(208,67,43,.6),0 0 14px 2px rgba(208,67,43,.55),0 0 32px 6px rgba(208,67,43,.25)}
.btn:active{transform:none;box-shadow:none}
@media (prefers-reduced-motion:reduce){.btn{transition:none}.btn:hover{transform:none}}

/* Hub */
.hub{grid-template-columns:minmax(0,1fr)!important}
.hub article{max-width:860px}
.stance{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:18px 0;margin:8px 0 8px}
.stance p{margin:0;color:var(--ink-2);font-size:1.05rem}.stance .eyebrow{margin-bottom:8px}
.topic{scroll-margin-top:24px}
.topic h2{margin-top:48px}
.topic .related{grid-template-columns:1fr}