/* Islands of Stability - site design tokens and layout
   Design from feedback4 (30 September 2026): warm paper, dark masthead and footer, Newsreader for
   headings, Instrument Sans for text, JetBrains Mono for labels; amber for the one accent, teal for
   what has been measured. Every page shares these rules; pages add their own <style> for their figures. */
:root {
  color-scheme: light;
  --page: #f4f2ed;
  --surface: #fbfaf7;
  --surface-2: #ebe8e1;
  --surface-3: #e7e3da;
  --ink: #17191b;
  --ink-2: #3d4043;
  --ink-3: #595c5f;
  --muted: #8d887c;
  --hairline: #d6d2c8;
  --border: #c9c3b6;
  --accent: #2b8297;
  --accent-ink: #1c6074;
  --amber: oklch(0.8 0.13 75);
  --amber-hover: oklch(0.86 0.12 75);
  --good: #2b8297;
  --warn: #9a5a0c;
  --crit: #b32d2d;
  --dark-bg: #0e1519;
  --dark-bg-2: #080c0e;
  --dark-ink: #e9ecea;
  --dark-ink-2: #c9d1d2;
  --dark-muted: #9aa6a8;
  --dark-line: rgba(233,236,234,.1);
  --dark-line-2: rgba(233,236,234,.3);
  --seq-100:#d2e6ea; --seq-150:#bcdae0; --seq-200:#a3cdd6; --seq-250:#8ac0cb; --seq-300:#6fb2c0;
  --seq-350:#55a3b4; --seq-400:#3c93a7; --seq-450:#2b8297; --seq-500:#237186; --seq-550:#1c6074;
  --seq-600:#165062; --seq-650:#104150; --seq-700:#0c333f;
  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --sans: "Instrument Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --measure: 68ch;
  --wrap: 82.5rem;
  --gutter: clamp(20px, 4vw, 48px);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --page: #0e1519; --surface: #141c21; --surface-2: #1a232a; --surface-3: #202a31;
    --ink: #e9ecea; --ink-2: #c9d1d2; --ink-3: #b9c3c4; --muted: #9aa6a8;
    --hairline: rgba(233,236,234,.12); --border: rgba(233,236,234,.22);
    --accent: #6fb2c0; --accent-ink: #8ac0cb;
    --good: #6fb2c0; --warn: oklch(0.8 0.13 75); --crit: #e66767;
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --page: #0e1519; --surface: #141c21; --surface-2: #1a232a; --surface-3: #202a31;
  --ink: #e9ecea; --ink-2: #c9d1d2; --ink-3: #b9c3c4; --muted: #9aa6a8;
  --hairline: rgba(233,236,234,.12); --border: rgba(233,236,234,.22);
  --accent: #6fb2c0; --accent-ink: #8ac0cb;
  --good: #6fb2c0; --warn: oklch(0.8 0.13 75); --crit: #e66767;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--page); color: var(--ink);
  font-family: var(--sans); font-size: 16px; line-height: 1.55;
  -webkit-font-smoothing: antialiased; font-feature-settings: "kern", "liga";
}
::selection { background: oklch(0.8 0.12 75); color: #17191b; }
:focus-visible { outline: 2px solid var(--amber); outline-offset: 2px; }
a { color: inherit; text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 3px; text-decoration-color: color-mix(in srgb, currentColor 35%, transparent); }
a:hover { text-decoration-color: currentColor; }
h1, h2, h3, h4 { font-family: var(--serif); font-weight: 400; line-height: 1.1; margin: 0 0 .5rem; letter-spacing: -0.02em; text-wrap: balance; }
h1 { font-size: clamp(2.2rem, 4.6vw, 3.6rem); font-weight: 300; line-height: 1.02; letter-spacing: -0.025em; }
h2 { font-size: clamp(1.7rem, 3vw, 2.5rem); margin-top: 2.75rem; }
h3 { font-size: 1.45rem; margin-top: 1.75rem; letter-spacing: -0.01em; }
h4 { font-size: 1.2rem; }
p { margin: 0 0 1rem; max-width: var(--measure); text-wrap: pretty; }
ul, ol { max-width: var(--measure); padding-left: 1.25rem; }
li { margin: .25rem 0; }
small, .small { font-size: .875rem; color: var(--ink-2); }
.muted { color: var(--muted); }
code, .mono { font-family: var(--mono); font-size: .9em; }
hr { border: 0; border-top: 1px solid var(--hairline); margin: 2.5rem 0; }

/* Labels: the small uppercase mono line above a section */
.kicker, .eyebrow { font-family: var(--mono); font-size: 12px; letter-spacing: .12em; text-transform: uppercase; color: var(--ink-3); }

.mock-ribbon {
  background: var(--dark-bg-2); color: #b9c3c4; font-family: var(--mono); font-size: 12px; letter-spacing: .02em;
  padding: 8px var(--gutter); display: flex; flex-wrap: wrap; gap: 6px 18px; align-items: center;
}
.mock-ribbon::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--amber); flex: none; }
.mock-ribbon a { color: var(--dark-ink); margin-left: auto; }
.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }

header.site {
  background: var(--dark-bg); color: var(--dark-ink); border-bottom: 1px solid var(--dark-line);
  position: sticky; top: 0; z-index: 10;
}
header.site .wrap { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 14px 32px; padding-top: 18px; padding-bottom: 18px; }
.brand { font-family: var(--serif); font-size: 22px; letter-spacing: -.01em; color: var(--dark-ink); text-decoration: none; white-space: nowrap; display: inline-flex; align-items: baseline; gap: 12px; }
.brand-mark { height: 28px; width: auto; align-self: center; flex: none; }
.brand .v { font-family: var(--mono); font-size: 11px; color: var(--dark-muted); border: 1px solid rgba(233,236,234,.2); padding: 2px 7px; border-radius: 3px; letter-spacing: 0; }
nav.primary { display: flex; flex-wrap: wrap; gap: 6px 28px; align-items: center; font-size: 15px; max-width: 100%; }
nav.primary a { color: var(--dark-ink-2); text-decoration: none; padding: .2rem 0; border-bottom: 2px solid transparent; white-space: nowrap; }
nav.primary a:hover { color: #fff; }
nav.primary a[aria-current="page"] { color: #fff; border-bottom-color: var(--amber); }
nav.primary a[href^="newsletter"], nav.primary a[href^="/newsletter"] { background: var(--amber); color: var(--dark-bg); padding: 7px 14px; border-radius: 3px; font-weight: 500; border: 0; }
nav.primary a[href^="newsletter"]:hover, nav.primary a[href^="/newsletter"]:hover { background: var(--amber-hover); color: var(--dark-bg); }
.subnav { border-bottom: 1px solid var(--hairline); background: var(--surface); }
.subnav .wrap { display: flex; gap: 1rem; overflow-x: auto; padding-top: .55rem; padding-bottom: .55rem; font-size: 14px; }
.subnav a { color: var(--ink-2); text-decoration: none; white-space: nowrap; }
.subnav a[aria-current="page"] { color: var(--ink); font-weight: 600; }

main { padding: 2.5rem 0 4rem; }
.hero { padding: 1rem 0 1rem; }
.hero .kicker { margin-bottom: 1rem; }
.hero .sub { font-family: var(--serif); font-size: clamp(1.25rem, 2.2vw, 1.6rem); line-height: 1.3; color: var(--ink-2); max-width: 40ch; margin: .5rem 0 1.25rem; }
.hero .thesis { font-family: var(--serif); font-size: clamp(1.2rem, 2vw, 1.5rem); line-height: 1.35; color: var(--ink); max-width: 44ch; margin: .75rem 0 1rem; }
.hero .scope { font-size: .95rem; color: var(--ink-2); max-width: var(--measure); }
.badges { display: flex; flex-wrap: wrap; gap: .5rem; margin: 0 0 1.5rem; }
.badge { font-family: var(--mono); font-size: 11px; letter-spacing: .03em; border: 1px solid var(--border); border-radius: 3px; padding: 3px 8px; color: var(--ink-2); background: transparent; }
.badge.ok { border-color: var(--good); color: var(--good); }
.badge.pending { border-color: var(--warn); color: var(--warn); }
.badge.draft, .badge.neutral { color: var(--ink-2); border-color: var(--border); }

.figure { background: var(--surface); border: 1px solid var(--border); border-radius: 2px; padding: 1rem; margin: 1.5rem 0; }
.figure figcaption { font-size: .875rem; line-height: 1.5; color: var(--ink-2); margin-top: .6rem; max-width: none; }
.figure svg { width: 100%; height: auto; display: block; }

.grid { display: grid; gap: 12px; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); margin: 1.5rem 0; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: 2px; padding: 22px 22px 20px; display: flex; flex-direction: column; gap: .5rem; }
.card h3 { margin: 0; font-size: 1.4rem; }
.card p { margin: 0; font-size: .92rem; color: var(--ink-2); }
.card .num { font-family: var(--mono); font-size: 11px; color: var(--ink-3); }
.card a.cta { margin-top: auto; padding-top: .5rem; font-size: .9rem; font-weight: 500; text-decoration: none; }
.card a.cta:hover { text-decoration: underline; }
.card a.cta::after { content: " \2192"; }

.two-col { display: grid; gap: 2rem; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

table { border-collapse: collapse; width: 100%; font-size: .92rem; margin: 1rem 0 1.5rem; }
th, td { text-align: left; vertical-align: top; padding: .6rem .6rem; border-bottom: 1px solid var(--hairline); }
th { font-family: var(--mono); font-weight: 500; color: var(--ink-3); font-size: 11px; letter-spacing: .1em; text-transform: uppercase; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; font-family: var(--mono); font-size: .85rem; }
.table-scroll { overflow-x: auto; }

.prop { border-top: 1px solid var(--hairline); padding: 1.5rem 0; }
.prop:last-of-type { border-bottom: 1px solid var(--hairline); }
.prop .n { font-family: var(--mono); color: var(--ink-3); font-size: 13px; }
.prop h3 { margin-top: .25rem; }
.prop dl { display: grid; grid-template-columns: max-content 1fr; gap: .35rem 1rem; max-width: var(--measure); margin: 1rem 0 0; }
.prop dt { font-family: var(--mono); font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: var(--ink-3); padding-top: .25rem; }
.prop dd { margin: 0; }
/* Chip rule: teal fill means measured or built; the warm accent means "not yet run / zero";
   every other state is neutral ink in an outline. */
.status { font-family: var(--mono); font-size: 11px; letter-spacing: .03em; padding: 3px 9px; border-radius: 2px; border: 1px solid var(--border); white-space: nowrap; color: var(--ink-2); }
.status.live { color: var(--page); background: var(--good); border-color: var(--good); }
.status.prereg, .status.pending { color: var(--warn); border-color: var(--warn); }
.status.none, .status.draft, .status.framing { color: var(--ink-2); border-color: var(--border); }
.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.status.kind { color: var(--ink); background: var(--surface-2); border-color: var(--border); }

/* Evidence ledger on the home page and the propositions index on the theory page */
.ledger { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); margin: 1rem 0 1.5rem; }
.ledger .stat .value { font-size: 1.7rem; }
.index-table td:first-child { font-family: var(--mono); font-size: 13px; color: var(--ink-3); white-space: nowrap; }
.last-changed { font-family: var(--mono); font-size: 11.5px; color: var(--dark-muted); }
.diagram { color: var(--ink-2); font-family: var(--sans); font-size: 12px; }

.plain { list-style: none; padding: 0; max-width: var(--measure); }
.plain li { display: grid; grid-template-columns: 3.2rem 1fr; gap: .5rem; padding: .55rem 0; border-top: 1px solid var(--hairline); }
.plain li:last-child { border-bottom: 1px solid var(--hairline); }
.plain .k { font-family: var(--mono); font-size: 13px; color: var(--ink-3); padding-top: .15rem; }
.paths { display: grid; gap: .5rem 1.5rem; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); max-width: var(--wrap); margin: 1rem 0 1.5rem; }
.paths div { font-size: .95rem; border-left: 2px solid var(--hairline); padding-left: .75rem; }
.paths strong { display: block; font-family: var(--mono); font-size: 11px; text-transform: uppercase; letter-spacing: .1em; color: var(--ink-3); font-weight: 500; }
.checklist { list-style: none; padding: 0; max-width: var(--measure); }
.checklist li { display: grid; grid-template-columns: max-content 1fr; gap: .75rem; padding: .5rem 0; border-top: 1px solid var(--hairline); align-items: start; }
.checklist li:last-child { border-bottom: 1px solid var(--hairline); }
.glossary dl { display: grid; grid-template-columns: max-content 1fr; gap: .4rem 1rem; max-width: var(--measure); }
.glossary dt { font-weight: 600; font-size: .95rem; }
.glossary dd { margin: 0; font-size: .95rem; color: var(--ink-2); }
ol.refs { list-style: none; padding: 0; margin: .75rem 0 1rem; max-width: var(--measure); }
ol.refs li { margin: 0 0 .6rem; padding-left: 1.25rem; text-indent: -1.25rem; font-size: .95rem; color: var(--ink-2); }
ol.refs a { overflow-wrap: anywhere; }
ol.refs li:target, #ref-fields:target { outline: 2px solid var(--amber); outline-offset: 4px; }
details.sources { margin: .75rem 0 0; max-width: var(--measure); border-top: 1px solid var(--hairline); }
details.sources summary { cursor: pointer; font-size: 13px; color: var(--ink-2); padding: .5rem 0; font-family: var(--mono); }
details.sources dl { margin-top: .25rem; }
.use-now { display: grid; gap: 12px; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); margin: 1rem 0 1.5rem; }
.author { border-top: 1px solid var(--hairline); padding-top: 1.25rem; margin-top: 2rem; font-size: .95rem; color: var(--ink-2); max-width: var(--measure); }
@media (max-width: 640px) { .plain li, .glossary dl, .checklist li { grid-template-columns: 1fr; } }
@media print { details.sources { display: block; } details.sources[open] summary { display: none; } }

.callout { background: var(--surface-2); border-left: 3px solid var(--amber); padding: .9rem 1.1rem; border-radius: 0 2px 2px 0; margin: 1.5rem 0; max-width: var(--measure); }
.callout p:last-child { margin-bottom: 0; }
.note { font-size: .875rem; color: var(--ink-2); }

.stat-row { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); margin: 1.25rem 0; }
.stat { background: var(--surface); border: 1px solid var(--border); border-radius: 2px; padding: .9rem 1rem; }
.stat .label { font-size: 13px; color: var(--ink-3); }
.stat .value { font-family: var(--serif); font-size: 2.2rem; line-height: 1.05; letter-spacing: -.02em; margin: .2rem 0; }
.stat .foot { font-size: 13px; line-height: 1.45; color: var(--ink-3); }

.btn { display: inline-block; border: 1px solid var(--ink); color: var(--ink); background: transparent; padding: 10px 16px; border-radius: 3px; text-decoration: none; font-size: 14px; font-weight: 500; line-height: 1.3; cursor: pointer; font-family: var(--sans); }
.btn:hover { background: var(--ink); color: var(--page); }
.btn.primary { background: var(--amber); color: #0e1519; border-color: var(--amber); font-weight: 600; }
.btn.primary:hover { background: var(--amber-hover); border-color: var(--amber-hover); color: #0e1519; }
.btn + .btn { margin-left: .5rem; }

footer.site { background: var(--dark-bg); color: var(--dark-muted); border-top: 1px solid var(--dark-line); padding: 20px 0 28px; font-family: var(--mono); font-size: 11.5px; line-height: 1.6; }
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 10px 28px; justify-content: space-between; }
footer.site a { color: var(--dark-ink-2); }

@media (max-width: 640px) {
  header.site { position: static; }
  header.site .wrap { padding-top: 14px; padding-bottom: 14px; }
  nav.primary { gap: 6px 18px; }
  .status { white-space: normal; }
  .prop dl { grid-template-columns: 1fr; }
  .btn + .btn { margin-left: 0; margin-top: .5rem; }
}

@media print {
  :root { color-scheme: light; }
  body { font-size: 11pt; background: #fff; }
  header.site { position: static; }
  .mock-ribbon, header.site, footer.site { -webkit-print-color-adjust: exact; print-color-adjust: exact; }
  .figure, .card, .prop, .stat, .callout, table, details { break-inside: avoid; }
  h2, h3 { break-after: avoid; }
  .badge, .status, .figure, .card, .stat, .callout, svg * { -webkit-print-color-adjust: exact; print-color-adjust: exact; }
  nav.primary a[aria-current="page"] { border-bottom-color: var(--amber); }
  .btn { border-color: var(--ink); }
  details { display: block; }
  .print-break { break-before: page; }
}