/* Learn section: the landing page's look, for long-form reading. */
:root {
  color-scheme: dark;
  --bg: #000; --panel: #070708; --rule: #1d1d21; --rule-2: #2a2a30;
  --ink: #d6d6d6; --ink-2: #8e8e96; --ink-3: #5c5c64; --pos: #a77bff;
  --display: "Martian Mono", "JetBrains Mono", ui-monospace, Menlo, Consolas, monospace;
  --mono: "JetBrains Mono", ui-monospace, Menlo, Consolas, monospace;
  --gut: max(16px, env(safe-area-inset-left, 0px));
}
* { box-sizing: border-box; }
html { background: var(--bg); }
body { margin: 0; background: var(--bg); color: var(--ink); font: 400 15px/1.75 var(--mono); -webkit-font-smoothing: antialiased; }
a { color: #fff; text-decoration-color: var(--pos); text-underline-offset: 3px; }
a:hover { color: var(--pos); }
::selection { background: var(--pos); color: #000; }
:focus-visible { outline: 1px solid var(--pos); outline-offset: 3px; }
.lab { font: 500 10px/1.2 var(--mono); letter-spacing: .2em; text-transform: uppercase; color: var(--ink-3); }

.bar { position: sticky; top: 0; z-index: 5; height: 30px; display: flex; align-items: center; gap: 18px; padding: 0 var(--gut); background: rgba(0,0,0,.86); border-bottom: 1px solid var(--rule); backdrop-filter: blur(6px); }
.bar .mark { display: inline-flex; align-items: center; gap: 10px; font: 800 11px/1 var(--display); letter-spacing: .38em; color: #fff; text-decoration: none; }
.bar nav { display: flex; gap: 2px; }
.bar nav a { font: 500 10px/1 var(--mono); letter-spacing: .16em; text-transform: uppercase; color: var(--ink-2); text-decoration: none; padding: 6px 8px; }
.bar nav a:hover { color: #fff; background: #141416; }
.bar .sp { flex: 1; }
.bar .in { font: 500 10px/1 var(--mono); letter-spacing: .16em; text-transform: uppercase; color: #000; background: var(--ink); padding: 7px 10px; text-decoration: none; }
.bar .in:hover { background: var(--pos); color: #000; }
@media (max-width: 640px) { .bar nav a:not(:first-child) { display: none; } }

main { max-width: 760px; margin: 0 auto; padding: 34px var(--gut) 60px; }
.hub { max-width: 1120px; }
.crumbs { font-size: 11px; color: var(--ink-3); margin-bottom: 26px; }
.crumbs a { color: var(--ink-2); text-decoration: none; }
.crumbs a:hover { color: #fff; }
.kicker { margin: 0 0 12px; color: var(--pos); text-transform: none; letter-spacing: .1em; }
/* Greek kickers carry σ: uppercasing would turn it into Σ (a sum) */
.cards .lab { text-transform: none; letter-spacing: .1em; }
h1 { margin: 0 0 18px; font: 800 clamp(26px, 4.6vw, 42px)/1.12 var(--display); color: #fff; letter-spacing: -.01em; }
h2 { margin: 44px 0 12px; font: 800 17px/1.35 var(--display); color: #fff; }
.lede { font-size: 17px; line-height: 1.7; color: var(--ink); margin: 0 0 8px; }
p, li { color: #c4c4ca; }
b, strong { color: #fff; font-weight: 500; }
ul { padding-left: 1.1em; }
li { margin: 6px 0; }
.eq { font: 500 15px/1.9 var(--mono); color: #fff; background: var(--panel); border: 1px solid var(--rule-2); border-left: 2px solid var(--pos); padding: 12px 16px; overflow-x: auto; white-space: nowrap; }
.note { font-size: 12px; color: var(--ink-3); }
.t { width: 100%; border-collapse: collapse; font-size: 13px; margin: 14px 0; display: block; overflow-x: auto; }
.t th { text-align: left; font: 500 10px/1.2 var(--mono); letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); padding: 8px 10px 8px 0; border-bottom: 1px solid var(--rule-2); }
.t td { padding: 8px 10px 8px 0; border-bottom: 1px solid var(--rule); vertical-align: top; color: #c4c4ca; }
.shot { margin: 40px 0 0; }
.shot img { display: block; width: 100%; height: auto; border: 1px solid var(--rule-2); background: #050505; }
.shot figcaption { font-size: 12px; color: var(--ink-2); margin-top: 8px; }

.faq details { border-top: 1px solid var(--rule); padding: 12px 0; }
.faq details:last-child { border-bottom: 1px solid var(--rule); }
.faq summary { cursor: pointer; color: #fff; font-weight: 500; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before { content: "+ "; color: var(--pos); }
.faq details[open] summary::before { content: "− "; }
.faq details div { color: #c4c4ca; margin-top: 8px; }

.cta { margin: 48px 0 0; border: 1px solid var(--rule-2); background: var(--panel); padding: 20px; }
.cta p { margin: 0 0 14px; }
.btn { display: inline-block; font: 500 11px/1 var(--mono); letter-spacing: .18em; text-transform: uppercase; padding: 13px 16px; border: 1px solid var(--rule-2); color: var(--ink); background: #000; text-decoration: none; margin: 4px 6px 0 0; }
.btn:hover { border-color: var(--pos); color: #fff; }
.btn.solid { background: #fff; color: #000; border-color: #fff; }
.btn.solid:hover { background: var(--pos); border-color: var(--pos); color: #000; }

.related ul, .cards { list-style: none; padding: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 0; border-top: 1px solid var(--rule); }
.related { margin-top: 40px; }
.related li, .cards li { margin: 0; border-bottom: 1px solid var(--rule); }
.related a, .cards a { display: grid; gap: 4px; padding: 14px 14px 14px 0; text-decoration: none; }
.related a b, .cards a b { color: #fff; font-weight: 500; }
.related a span, .cards a span { font-size: 12px; color: var(--ink-2); }
.related a:hover b, .cards a:hover b { color: var(--pos); }
.hub section h2 { border-top: 1px solid var(--rule-2); padding-top: 14px; }
.cards { grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); column-gap: 28px; border-top: 0; }

.foot { border-top: 1px solid var(--rule); padding: 28px var(--gut) 50px; font-size: 12px; color: var(--ink-3); }
.foot .cols { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 18px; max-width: 1120px; margin: 0 auto 22px; }
.foot h2 { margin: 0 0 8px; }
.foot ul { list-style: none; padding: 0; margin: 0; }
.foot li { margin: 3px 0; }
.foot a { color: var(--ink-2); text-decoration: none; }
.foot a:hover { color: #fff; }
.foot p { max-width: 1120px; margin: 0 auto; color: var(--ink-3); }
.foot .mark { display: inline-flex; align-items: center; gap: 8px; vertical-align: -2px; font: 800 10px/1 var(--display); letter-spacing: .38em; color: var(--ink-2); margin-right: 10px; }
.disclaimer { margin: 36px 0 0; padding: 12px 14px; border: 1px solid var(--rule-2); font-size: 12px; color: var(--ink-2); }