:root {
  --ink: #1d1a26;
  --ink-soft: #4c4757;
  --muted: #837c8e;
  --bone: #f6f1e7;
  --paper: #fffdf8;
  --rule: #e4ddcd;
  --rule-strong: #cfc7b3;
  --plum: #4a2b6b;
  --plum-deep: #3a1f56;
  --plum-wash: #efe9f5;
  --brass: #a9761a;
  --brass-wash: #f8efd8;
  --sage: #2f7d5b;
  --sage-wash: #e6f2ec;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --fast: 200ms;
  --sans: "Inter", "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
  --mono: ui-monospace, "SFMono-Regular", "Cascadia Mono", Menlo, Consolas, monospace;
  --max: 1080px;
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bone);
  background-image: radial-gradient(circle at 1px 1px, rgba(74, 43, 107, 0.07) 1px, transparent 0);
  background-size: 26px 26px;
  color: var(--ink);
  font: 400 clamp(16px, 0.6vw + 14px, 17px) / 1.62 var(--sans);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { font-family: var(--serif); line-height: 1.14; letter-spacing: -0.015em; margin: 0; font-weight: 600; }
h1 { font-size: clamp(2.1rem, 4.6vw, 3.3rem); }
h2 { font-size: clamp(1.45rem, 2.2vw, 1.9rem); }
h3 { font-size: 1.1rem; letter-spacing: -0.006em; }
p { margin: 0 0 1em; }
a { color: var(--plum-deep); text-underline-offset: 3px; }
ul, ol { padding-left: 1.15em; margin: 0 0 1em; }
li { margin-bottom: 0.45em; }
strong { font-weight: 640; }
em { font-style: italic; }

.mono, .fig-tag, .mini-label, .note-tag, .watch-tag, .kicker, .crumb-line, .track-label { font-family: var(--mono); }

.skip { position: absolute; left: -9999px; top: 0; padding: 12px 18px; background: var(--plum); color: #fff; z-index: 20; text-decoration: none; }
.skip:focus { left: 12px; top: 12px; }

/* ---------------------------------------------------------------- masthead */
.top { position: sticky; top: 0; z-index: 10; background: var(--plum-deep); border-bottom: 3px solid var(--brass); }
.bar { max-width: var(--max); margin: 0 auto; padding: 12px 22px; display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.brand {
  display: inline-flex; align-items: center; gap: 10px; color: #fff; text-decoration: none;
  font-family: var(--serif); font-weight: 600; letter-spacing: -0.01em; margin-right: auto; font-size: 1.12rem;
}
.brand .mark {
  display: inline-grid; place-items: center; width: 30px; height: 30px; border-radius: 8px;
  background: var(--brass); color: var(--plum-deep); font: 700 0.8rem/1 var(--mono); letter-spacing: 0.03em;
}
.menu { display: flex; gap: 3px; flex-wrap: wrap; }
.menu a {
  color: #ddd2ea; text-decoration: none; font-size: 0.83rem; padding: 6px 10px; border-radius: 7px;
  border: 1px solid transparent;
  transition: color var(--fast) var(--ease), background var(--fast) var(--ease), border-color var(--fast) var(--ease);
}
.menu a:hover { color: #fff; background: #553377; border-color: #6a4a90; }
.menu a[aria-current="page"] { color: var(--plum-deep); background: var(--brass); border-color: var(--brass); }

/* ---------------------------------------------------------------- buttons */
.btn, .ghost {
  display: inline-flex; align-items: center; gap: 8px; padding: 11px 18px; border-radius: 9px;
  font-weight: 620; font-size: 0.9rem; text-decoration: none; border: 1px solid transparent;
  transition: transform var(--fast) var(--ease), background var(--fast) var(--ease), border-color var(--fast) var(--ease), color var(--fast) var(--ease);
}
.btn { background: var(--brass); color: #241705; }
.btn:hover { background: #c58f24; transform: translateY(-1px); }
.ghost { background: transparent; color: var(--ink); border-color: var(--rule-strong); }
.ghost:hover { border-color: var(--plum); color: var(--plum-deep); transform: translateY(-1px); }
.top .btn { padding: 8px 14px; font-size: 0.82rem; }

/* ---------------------------------------------------------------- shell */
.shell { max-width: var(--max); margin: 0 auto; padding: 0 22px 72px; }
main { display: block; }

.page-hero { padding: clamp(36px, 5.4vw, 62px) 0 28px; border-bottom: 1px solid var(--rule); margin-bottom: 36px; }
.crumb-line { font-size: 0.74rem; letter-spacing: 0.09em; text-transform: uppercase; color: var(--muted); margin-bottom: 14px; }
.eyebrow {
  display: inline-block; font-size: 0.71rem; letter-spacing: 0.13em; text-transform: uppercase;
  color: var(--plum); border: 1px solid var(--plum); background: var(--plum-wash);
  padding: 4px 10px; border-radius: 6px; margin-bottom: 16px;
}
.page-hero h1 { max-width: 24ch; }
.lede { max-width: 64ch; margin-top: 16px; color: var(--ink-soft); font-size: 1.06rem; }
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 22px; }

/* ---------------------------------------------------------------- blocks */
.block { margin-bottom: 48px; scroll-margin-top: 96px; }
.block > h2 { padding-bottom: 12px; margin-bottom: 18px; border-bottom: 2px solid var(--rule-strong); }
.block h2 { max-width: 30ch; }

.mini-nav {
  display: flex; align-items: center; gap: 7px; flex-wrap: wrap; padding: 12px 14px;
  background: var(--paper); border: 1px solid var(--rule); border-radius: 10px; margin-bottom: 30px;
}
.mini-label { font-size: 0.7rem; letter-spacing: 0.11em; text-transform: uppercase; color: var(--muted); margin-right: 4px; }
.mini-nav a {
  font-size: 0.8rem; text-decoration: none; color: var(--ink); padding: 4px 9px; border: 1px solid var(--rule);
  border-radius: 6px; background: var(--bone);
  transition: border-color var(--fast) var(--ease), background var(--fast) var(--ease), transform var(--fast) var(--ease);
}
.mini-nav a:hover { border-color: var(--plum); background: var(--plum-wash); transform: translateY(-1px); }

.note { background: var(--paper); border: 1px solid var(--rule); border-left: 4px solid var(--plum); padding: 16px 18px; border-radius: 9px; margin: 0 0 30px; }
.note p { margin: 6px 0 0; color: var(--ink-soft); font-size: 0.94rem; }
.note-tag { font-size: 0.68rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--plum); }
.note-warn { border-left-color: var(--brass); background: var(--brass-wash); }
.note-warn .note-tag { color: var(--brass); }

/* ---------------------------------------------------------------- figure cards */
.fig-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; margin: 22px 0 8px; }
.fig {
  background: var(--paper); border: 1px solid var(--rule); border-top: 3px solid var(--plum);
  border-radius: 10px; padding: 20px 18px 18px;
  transition: transform var(--fast) var(--ease), border-color var(--fast) var(--ease), box-shadow var(--fast) var(--ease);
}
.fig:hover { transform: translateY(-3px); box-shadow: 0 10px 26px rgba(58, 31, 86, 0.09); }
.fig-tag { display: inline-block; font-size: 0.66rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--muted); margin-bottom: 12px; }
.fig strong { display: block; font-family: var(--serif); font-size: clamp(1.9rem, 3.6vw, 2.6rem); line-height: 1; color: var(--plum-deep); letter-spacing: -0.02em; }
.fig .fig-cap { display: block; font-size: 0.86rem; color: var(--ink-soft); margin-top: 10px; }

/* ---------------------------------------------------------------- split comparison */
.split {
  display: grid; grid-template-columns: 1fr 1fr; gap: 0; margin: 22px 0 8px;
  background: var(--paper); border: 1px solid var(--rule); border-radius: 12px; overflow: hidden;
}
.track { padding: 20px 20px 22px; }
.track + .track { border-left: 1px solid var(--rule); }
.track-theory { background: var(--sage-wash); }
.track-you { background: var(--brass-wash); }
.track-label { display: inline-block; font-size: 0.67rem; letter-spacing: 0.13em; text-transform: uppercase; margin-bottom: 10px; }
.track-theory .track-label { color: var(--sage); }
.track-you .track-label { color: var(--brass); }
.track h3 { margin-bottom: 8px; }
.track p { font-size: 0.9rem; color: var(--ink-soft); margin: 0; }

/* ---------------------------------------------------------------- variance ladder */
.ladder { margin: 22px 0 8px; background: var(--paper); border: 1px solid var(--rule); border-radius: 12px; padding: 22px 20px 18px; }
.ladder-track { position: relative; height: 12px; border-radius: 6px; background: linear-gradient(90deg, var(--sage-wash), var(--plum-wash), var(--brass-wash)); border: 1px solid var(--rule); margin: 26px 0 14px; }
.ladder-stop { position: absolute; top: -6px; width: 24px; height: 24px; margin-left: -12px; border-radius: 50%; background: var(--paper); border: 2px solid var(--rule-strong); transition: transform var(--fast) var(--ease), border-color var(--fast) var(--ease); }
.ladder-stop:hover { transform: scale(1.2); border-color: var(--plum); }
.ladder-stop.on { background: var(--plum); border-color: var(--plum); }
.ladder-labels { display: flex; justify-content: space-between; gap: 10px; font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.05em; text-transform: uppercase; color: var(--muted); }

/* ---------------------------------------------------------------- worked example */
.worked { background: var(--plum-deep); color: #efe9f5; border-radius: 12px; padding: 20px 22px; margin: 22px 0 8px; }
.worked .kicker { display: block; font-size: 0.68rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--brass); margin-bottom: 12px; }
.worked p { margin: 0 0 10px; color: #d9cdea; font-size: 0.92rem; }
.worked .calc { display: block; font-family: var(--mono); font-size: 0.92rem; color: #fff; background: rgba(255, 255, 255, 0.07); border-radius: 8px; padding: 12px 14px; margin: 8px 0; overflow-x: auto; white-space: nowrap; }
.worked .calc .hl { color: var(--brass); }
.worked .verdict { font-family: var(--mono); font-size: 0.82rem; color: #c9b8e2; margin: 6px 0 0; }

/* ---------------------------------------------------------------- tables */
.table-wrap { overflow-x: auto; border: 1px solid var(--rule); border-radius: 12px; background: var(--paper); margin: 22px 0 8px; }
table.data { border-collapse: collapse; width: 100%; min-width: 660px; font-size: 0.89rem; }
table.data caption { text-align: left; padding: 14px 16px 0; font-size: 0.8rem; color: var(--muted); }
table.data th, table.data td { text-align: left; padding: 12px 16px; border-top: 1px solid var(--rule); vertical-align: top; }
table.data thead th { background: var(--plum-deep); color: #fff; font-size: 0.72rem; letter-spacing: 0.09em; text-transform: uppercase; font-weight: 600; border-top: 0; white-space: nowrap; }
table.data tbody tr { transition: background var(--fast) var(--ease); }
table.data tbody tr:hover { background: var(--plum-wash); }
table.data td:first-child { font-weight: 600; color: var(--ink); }

/* ---------------------------------------------------------------- faq */
.faq { display: grid; gap: 10px; margin: 22px 0 8px; }
.faq-item { background: var(--paper); border: 1px solid var(--rule); border-radius: 11px; overflow: hidden; }
.faq-item summary { cursor: pointer; padding: 16px 18px; font-weight: 620; font-size: 1rem; list-style: none; display: flex; gap: 12px; align-items: flex-start; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::before { content: "+"; font-family: var(--mono); color: var(--plum); flex: none; font-size: 1.15rem; line-height: 1.25; }
.faq-item[open] summary::before { content: "–"; }
.faq-body { padding: 0 18px 6px 46px; color: var(--ink-soft); font-size: 0.94rem; }
.faq-body p { margin: 0 0 14px; }

/* ---------------------------------------------------------------- lists */
ul.plain, ol.plain { list-style: none; padding-left: 0; margin: 18px 0 8px; }
ul.plain > li, ol.plain > li {
  background: var(--paper); border: 1px solid var(--rule); border-left: 3px solid var(--rule-strong);
  border-radius: 9px; padding: 13px 16px; margin-bottom: 10px;
  transition: border-color var(--fast) var(--ease), transform var(--fast) var(--ease);
}
ul.plain > li:hover, ol.plain > li:hover { border-left-color: var(--plum); transform: translateX(2px); }
ol.plain { counter-reset: step; }
ol.plain > li { counter-increment: step; padding-left: 52px; position: relative; }
ol.plain > li::before { content: counter(step, decimal-leading-zero); position: absolute; left: 16px; top: 13px; font-family: var(--mono); font-size: 0.78rem; color: var(--plum); letter-spacing: 0.06em; }
ul.checklist > li { border-left-color: var(--sage); }

/* ---------------------------------------------------------------- cta + disclosure */
.next-step {
  display: flex; align-items: center; gap: 22px; justify-content: space-between; flex-wrap: wrap;
  background: var(--plum); color: #f0eaf7; border-radius: 12px; padding: 24px 26px; margin: 42px 0 26px;
}
.next-step h2 { color: #fff; font-size: 1.24rem; margin: 4px 0 6px; }
.next-step p { margin: 0; color: #cdbfe0; font-size: 0.9rem; max-width: 52ch; }
.next-step .kicker { display: inline-block; font-size: 0.68rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--brass); }
.next-step .btn { background: var(--brass); color: #241705; }
.next-step .btn:hover { background: #c58f24; }

.disclosure { background: var(--paper); border: 1px solid var(--rule); border-radius: 10px; padding: 16px 18px; font-size: 0.85rem; color: var(--ink-soft); }
.disclosure strong { color: var(--ink); }
.link-out { color: var(--plum-deep); font-weight: 600; }

/* ---------------------------------------------------------------- footer */
.footer { background: var(--plum-deep); color: #cbbfdd; padding: 46px 22px 30px; margin-top: 24px; }
.foot-grid { max-width: var(--max); margin: 0 auto; display: grid; grid-template-columns: 1.6fr 1fr 1fr; gap: 30px; }
.footer .brand { color: #fff; margin-bottom: 10px; }
.footer p { font-size: 0.86rem; color: #a99abe; }
.footer strong { display: block; color: #fff; font-size: 0.75rem; letter-spacing: 0.11em; text-transform: uppercase; margin-bottom: 12px; font-family: var(--mono); }
.footer a { display: block; color: #d3c8e4; text-decoration: none; font-size: 0.88rem; padding: 4px 0; transition: color var(--fast) var(--ease), transform var(--fast) var(--ease); }
.footer a:hover { color: #fff; transform: translateX(2px); }
.fine { max-width: var(--max); margin: 30px auto 0; font-size: 0.78rem; color: #9c8db4; border-top: 1px solid #4d3273; padding-top: 20px; }

/* ---------------------------------------------------------------- narrow */
@media (max-width: 900px) {
  .fig-grid { grid-template-columns: 1fr; }
  .split { grid-template-columns: 1fr; }
  .track + .track { border-left: 0; border-top: 1px solid var(--rule); }
  .foot-grid { grid-template-columns: 1fr; gap: 22px; }
}
@media (max-width: 620px) {
  .bar { padding: 10px 16px; gap: 10px; }
  .shell { padding: 0 16px 56px; }
  .menu a { padding: 5px 8px; font-size: 0.79rem; }
  .ladder-labels { font-size: 0.62rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .fig:hover, .btn:hover, .ghost:hover, .mini-nav a:hover, ul.plain > li:hover, ol.plain > li:hover,
  .footer a:hover, .ladder-stop:hover {
    transform: none;
  }
}