/* AI Systems Orchestration — editorial reading design.
   New long form style using the shared repo DNA:
   mono uppercase kickers · subtle grid backdrop · CSS variable theming. */

:root {
  --sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --serif: 'Newsreader', Georgia, 'Times New Roman', serif;
  --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;

  --bg: #faf9f6;
  --bg-raise: #ffffff;
  --panel: #f2f1ec;
  --panel-2: #ecebe4;
  --ink: #1c2536;
  --ink-soft: #3d4d66;
  --dim: #66748c;
  --faint: #93a0b4;
  --border: #e3e1d8;
  --border-2: #d3d1c6;
  --accent: #2456d6;
  --accent-ink: #1d47b4;
  --accent-soft: rgba(36, 86, 214, 0.09);
  --warm: #b45309;
  --ok: #147a4d;
  --grid-line: rgba(28, 37, 54, 0.035);
  --shadow: 0 1px 2px rgba(20, 26, 40, 0.05), 0 10px 34px -18px rgba(20, 26, 40, 0.18);
  --shadow-lift: 0 2px 4px rgba(20, 26, 40, 0.06), 0 18px 50px -20px rgba(20, 26, 40, 0.28);
  --plate-bg: #ffffff;
  --code-bg: #f0efe9;
  --code-ink: #2d3a52;
  --selection: rgba(36, 86, 214, 0.16);

  --fig-ink: #16233c;
  --fig-dim: #5b6b83;
  --fig-edge: #8296b3;
  --fig-node: #ffffff;
  --fig-stroke: #c5d0e2;
  --fig-lane: rgba(28, 37, 54, 0.033);
  --fig-accent: #2563eb;
  --fig-accent-soft: rgba(37, 99, 235, 0.08);
  --fig-warn: #b45309;
  --fig-warn-soft: rgba(180, 83, 9, 0.08);
  --fig-ok: #147a4d;
  --fig-ok-soft: rgba(20, 122, 77, 0.07);
  --fig-chip: #eef0f3;
}

[data-theme="dark"] {
  --bg: #0b0f19;
  --bg-raise: #101626;
  --panel: #121828;
  --panel-2: #182034;
  --ink: #dfe6f2;
  --ink-soft: #b5c1d6;
  --dim: #8493ac;
  --faint: #5b6a84;
  --border: #202940;
  --border-2: #2b3652;
  --accent: #7ea2f8;
  --accent-ink: #a5bffa;
  --accent-soft: rgba(126, 162, 248, 0.12);
  --warm: #e8a75d;
  --ok: #4fc48d;
  --grid-line: rgba(223, 230, 242, 0.028);
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 14px 40px -18px rgba(0, 0, 0, 0.6);
  --shadow-lift: 0 2px 4px rgba(0, 0, 0, 0.5), 0 22px 60px -20px rgba(0, 0, 0, 0.75);
  --plate-bg: #f4f5f8;
  --code-bg: #151d30;
  --code-ink: #c4d0e6;
  --selection: rgba(126, 162, 248, 0.25);

  --fig-ink: #dfe6f2;
  --fig-dim: #8ea0bc;
  --fig-edge: #5f7397;
  --fig-node: #141c30;
  --fig-stroke: #33405e;
  --fig-lane: rgba(223, 230, 242, 0.04);
  --fig-accent: #7ea2f8;
  --fig-accent-soft: rgba(126, 162, 248, 0.12);
  --fig-warn: #e8a75d;
  --fig-warn-soft: rgba(232, 167, 93, 0.12);
  --fig-ok: #4fc48d;
  --fig-ok-soft: rgba(79, 196, 141, 0.1);
  --fig-chip: #1e2842;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 40px; }
body {
  font-family: var(--serif);
  background: var(--bg);
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
body::before {
  content: "";
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: radial-gradient(ellipse 100% 80% at 50% 0%, #000 30%, transparent 90%);
}
::selection { background: var(--selection); }
a { color: var(--accent-ink); text-decoration-color: color-mix(in srgb, var(--accent) 40%, transparent); text-underline-offset: 3px; }
a:hover { text-decoration-color: var(--accent); }

.skip-link {
  position: fixed;
  z-index: 300;
  top: -80px;
  left: 16px;
  padding: 10px 14px;
  border: 1px solid var(--border-2);
  border-radius: 10px;
  color: var(--bg);
  background: var(--ink);
  box-shadow: var(--shadow-lift);
  font: 650 12px/1 var(--sans);
  text-decoration: none;
}
.skip-link:focus {
  top: 16px;
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

/* ---------- progress bar ---------- */
.progress {
  position: fixed; top: 0; left: 0; height: 3px; width: 0;
  background: linear-gradient(90deg, var(--accent), color-mix(in srgb, var(--accent) 60%, var(--warm)));
  z-index: 200; transition: width 80ms linear;
}

/* ---------- layout ---------- */
.shell { position: relative; z-index: 1; display: flex; min-height: 100vh; }

.sidebar {
  width: 292px; flex: none;
  position: sticky; top: 0; height: 100vh; overflow-y: auto;
  border-right: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg) 80%, var(--bg-raise));
  padding: 28px 22px 22px;
  scrollbar-width: thin;
  font-family: var(--sans);
  display: flex; flex-direction: column; gap: 6px;
}
.sidebar .brand { display: block; text-decoration: none; color: var(--ink); margin-bottom: 14px; }
.sidebar .brand .k { font: 600 10px/1 var(--mono); letter-spacing: 0.18em; color: var(--accent); text-transform: uppercase; }
.sidebar .brand .t { display: block; margin-top: 7px; font: 800 15.5px/1.3 var(--sans); letter-spacing: -0.01em; }

.sb-part { margin-top: 14px; }
.sb-part .ph {
  font: 600 10px/1.6 var(--mono); letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--faint); padding: 0 8px 5px;
}
.sb-ch {
  display: flex; align-items: baseline; gap: 9px;
  padding: 5.5px 8px; border-radius: 7px;
  text-decoration: none; color: var(--dim);
  font: 450 13px/1.35 var(--sans);
  transition: background 120ms ease, color 120ms ease;
}
.sb-ch:hover { background: var(--accent-soft); color: var(--ink); }
.sb-ch .n { font: 500 10.5px/1 var(--mono); color: var(--faint); width: 18px; flex: none; }
.sb-ch.is-current {
  background: var(--accent-soft); color: var(--ink); font-weight: 600;
  box-shadow: inset 2.5px 0 0 var(--accent);
}
.sb-ch.is-current .n { color: var(--accent); }

.sb-foot { margin-top: auto; padding-top: 18px; display: flex; flex-direction: column; gap: 10px; }
.path-chip {
  display: none; align-items: center; gap: 8px; padding: 8px 10px;
  border: 1px solid var(--border); border-radius: 9px; background: var(--bg-raise);
  font: 500 11.5px/1.4 var(--sans); color: var(--dim);
}
.path-chip.active { display: flex; }
.path-chip b { color: var(--ink); font-weight: 650; }
.path-chip button {
  margin-left: auto; border: 0; background: none; color: var(--faint);
  font: 500 10px/1 var(--mono); letter-spacing: 0.08em; cursor: pointer; text-transform: uppercase;
}
.path-chip button:hover { color: var(--warm); }

.theme-toggle {
  display: flex; align-items: center; gap: 8px;
  border: 1px solid var(--border); border-radius: 9px;
  background: var(--bg-raise); color: var(--dim);
  padding: 8px 12px; cursor: pointer;
  font: 500 12px/1 var(--sans);
  transition: color 120ms ease, border-color 120ms ease;
}
.theme-toggle:hover { color: var(--ink); border-color: var(--border-2); }
.theme-toggle .sw { width: 26px; height: 15px; border-radius: 8px; background: var(--panel-2); position: relative; flex: none; }
.theme-toggle .sw::after {
  content: ""; position: absolute; top: 2px; left: 2px; width: 11px; height: 11px;
  border-radius: 50%; background: var(--accent); transition: left 150ms ease;
}
[data-theme="dark"] .theme-toggle .sw::after { left: 13px; }

/* mobile top bar */
.topbar { display: none; }
.scrim { display: none; }

/* ---------- article ---------- */
.main { flex: 1; min-width: 0; }
.article { max-width: 720px; margin: 0 auto; padding: 64px 32px 90px; }

.crumb { font: 600 11px/1.7 var(--mono); letter-spacing: 0.16em; text-transform: uppercase; color: var(--accent); display: flex; gap: 12px; align-items: baseline; flex-wrap: wrap; }
.crumb > span:last-child { white-space: nowrap; }
.crumb .sep { color: var(--faint); }
.crumb .part { color: var(--faint); }

.ch-head { margin: 26px 0 8px; position: relative; }
.ch-head .bignum {
  position: absolute; top: -66px; right: -14px;
  font: 800 150px/1 var(--sans); letter-spacing: -0.05em;
  color: var(--ink); opacity: 0.045; pointer-events: none; user-select: none;
}
h1.ch-title {
  font: 800 clamp(34px, 5.4vw, 50px)/1.06 var(--sans);
  letter-spacing: -0.028em; color: var(--ink); margin: 0 0 18px;
}
.standfirst {
  font: italic 400 clamp(19px, 2.4vw, 22.5px)/1.5 var(--serif);
  color: var(--ink-soft); margin-bottom: 20px; max-width: 58ch;
}
.meta-row {
  display: flex; flex-wrap: wrap; gap: 16px; align-items: center;
  font: 500 12px/1 var(--sans); color: var(--dim);
  padding-bottom: 26px; border-bottom: 1px solid var(--border); margin-bottom: 34px;
}
.meta-row .m { display: inline-flex; align-items: center; gap: 6px; }
.meta-row .m::before { content: ""; width: 4px; height: 4px; border-radius: 50%; background: var(--accent); opacity: 0.7; }
.path-pos {
  display: none; padding: 4px 10px; border-radius: 20px;
  background: var(--accent-soft); color: var(--accent-ink); font-weight: 600;
}
.path-pos.active { display: inline-flex; }

/* ---------- prose ---------- */
.prose { font-size: 19.5px; line-height: 1.74; }
.prose > * + * { margin-top: 1.15em; }
.prose p { max-width: 66ch; }
.prose strong { font-weight: 650; color: var(--ink); }
.prose h2 {
  font: 700 27px/1.25 var(--sans); letter-spacing: -0.018em; color: var(--ink);
  margin-top: 2.2em; padding-top: 1.6em; border-top: 1px solid var(--border);
}
/* the chapter header already draws a divider — don't stack another on a leading h2 */
.prose > h2:first-child { margin-top: 0.4em; padding-top: 0; border-top: 0; }
.prose h2::before {
  content: attr(data-kick);
  display: block; font: 600 10.5px/1 var(--mono); letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 12px;
}
.prose h3 { font: 650 21px/1.3 var(--sans); letter-spacing: -0.012em; color: var(--ink); margin-top: 1.8em; }
.prose ul, .prose ol { padding-left: 1.35em; max-width: 62ch; }
.prose li { margin-top: 0.45em; }
.prose li::marker { color: var(--accent); font-family: var(--sans); font-size: 0.85em; }
.prose blockquote {
  border-left: 3px solid var(--accent); padding: 6px 0 6px 26px; margin: 1.8em 0;
  font: italic 500 clamp(21px, 2.6vw, 24px)/1.5 var(--serif); color: var(--ink);
}
.prose blockquote p { max-width: 52ch; }
.prose hr { border: 0; border-top: 1px solid var(--border); margin: 2.4em auto; width: 120px; }
.prose code {
  font: 500 0.78em/1.4 var(--mono); background: var(--code-bg); color: var(--code-ink);
  border: 1px solid var(--border); border-radius: 5px; padding: 0.12em 0.42em;
  overflow-wrap: anywhere;
}
.prose pre {
  background: var(--code-bg); border: 1px solid var(--border); border-radius: 12px;
  padding: 20px 24px; overflow-x: auto; box-shadow: var(--shadow);
  font: 450 14px/1.65 var(--mono);
}
.prose pre code { background: none; border: 0; padding: 0; font-size: inherit; color: var(--code-ink); }

.table-scroll { overflow-x: auto; margin: 1.8em 0; border: 1px solid var(--border); border-radius: 12px; box-shadow: var(--shadow); }
.prose table { border-collapse: collapse; width: 100%; font: 450 14.5px/1.55 var(--sans); background: var(--bg-raise); }
.prose th {
  font: 600 10.5px/1.4 var(--mono); letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--dim); text-align: left; padding: 12px 16px;
  border-bottom: 1px solid var(--border-2); background: var(--panel);
}
.prose td { padding: 12px 16px; border-bottom: 1px solid var(--border); vertical-align: top; color: var(--ink-soft); }
.prose tr:last-child td { border-bottom: 0; }
.prose td:first-child { font-weight: 600; color: var(--ink); }

/* ---------- figures ---------- */
figure.plate { margin: 2.3em -60px; }
@media (max-width: 1320px) { figure.plate { margin-left: 0; margin-right: 0; } }
figure.plate .frame {
  background: var(--plate-bg); border: 1px solid var(--border); border-radius: 14px;
  padding: 14px; box-shadow: var(--shadow);
}
figure.plate img { display: block; width: 100%; height: auto; border-radius: 8px; }
figure.plate.vertical .frame { max-width: 480px; margin: 0 auto; }
figure.plate figcaption {
  margin-top: 12px; padding: 0 6px;
  font: 450 12.5px/1.6 var(--sans); color: var(--dim);
}
figure.plate figcaption .fno { font: 600 10.5px/1 var(--mono); letter-spacing: 0.12em; color: var(--accent); margin-right: 9px; }

/* theme paired images — !important so figure img display rules never resurface the wrong variant */
.only-dark { display: none !important; }
[data-theme="dark"] .only-light { display: none !important; }
[data-theme="dark"] .only-dark { display: block !important; }

/* inline crafted diagrams */
figure.plate.diagram .frame { background: var(--bg-raise); padding: 20px 14px; }
.fg { display: block; width: 100%; height: auto; }
.fg text { font-family: var(--sans); fill: var(--fig-ink); }
.fg .fg-kick { font: 600 13px var(--mono); fill: var(--fig-accent); letter-spacing: 2.2px; }
.fg .fg-lanek { font: 600 11.5px var(--mono); fill: var(--fig-dim); letter-spacing: 1.8px; }
.fg .fg-lab { font-size: 16.5px; font-weight: 650; }
.fg .fg-sub { font-size: 13px; fill: var(--fig-dim); }
.fg .fg-sub2 { font-size: 12.5px; fill: var(--fig-dim); }
.fg .fg-tag { font: 600 11.5px var(--mono); fill: var(--fig-dim); letter-spacing: 1px; }
.fg .fg-chipt { font: 600 12px var(--mono); fill: var(--fig-ink); }
.fg .fg-node rect { fill: var(--fig-node); stroke: var(--fig-stroke); stroke-width: 1.4; }
.fg .fg-node.fg-acc rect { fill: var(--fig-accent-soft); stroke: var(--fig-accent); }
.fg .fg-node.fg-warn rect { fill: var(--fig-warn-soft); stroke: var(--fig-warn); }
.fg .fg-lane rect { fill: var(--fig-lane); stroke: var(--fig-stroke); stroke-width: 1; stroke-dasharray: 3 4; }
.fg .fg-note rect { fill: var(--fig-lane); stroke: var(--fig-stroke); stroke-width: 1; }
.fg .fg-slab rect { fill: var(--fig-chip); stroke: var(--fig-stroke); stroke-width: 1; }
.fg .fg-gr rect { fill: var(--fig-warn); opacity: 0.55; }
.fg .fg-chip rect { fill: var(--fig-chip); stroke: var(--fig-stroke); stroke-width: 1; }
.fg .fg-edge { stroke: var(--fig-edge); stroke-width: 1.7; fill: none; }
.fg .fg-dash { stroke-dasharray: 5 5; }
.fg .fg-ah { fill: var(--fig-edge); }
.fg .fg-ckpt { fill: var(--fig-accent); opacity: 0.85; }
.fg .fg-nochip rect { fill: transparent; stroke: var(--fig-stroke); stroke-width: 1.2; stroke-dasharray: 4 4; }
.fg .fg-nochip text { fill: var(--fig-dim); text-decoration: line-through; }
.fg .fg-seg rect { stroke: var(--fig-stroke); stroke-width: 1.2; }
.fg .fg-seg-a rect { fill: var(--fig-accent-soft); }
.fg .fg-seg-b rect { fill: var(--fig-chip); }
.fg .fg-seg-c rect { fill: var(--fig-ok-soft); }
.fg .fg-seg-d rect { fill: var(--fig-warn-soft); }
.fg .fg-seg-e rect { fill: var(--fig-lane); }
.fg .fg-venn { stroke-width: 1.6; }
.fg .fg-venn-a { fill: var(--fig-accent-soft); stroke: var(--fig-accent); }
.fg .fg-venn-b { fill: var(--fig-warn-soft); stroke: var(--fig-warn); }
.fg .fg-venn-c { fill: var(--fig-ok-soft); stroke: var(--fig-ok); }

/* ---------- scan layer: gist + jump ---------- */
.pk {
  display: block; font: 650 10.5px/1 var(--mono); letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 12px;
}
.jump {
  display: flex; flex-wrap: wrap; gap: 7px; align-items: center;
  margin: 0 0 10px; font-family: var(--sans);
}
.jump .pk { margin: 0 6px 0 0; display: inline-block; color: var(--faint); }
.jump a {
  font: 500 12px/1 var(--sans); color: var(--dim); text-decoration: none;
  border: 1px solid var(--border); border-radius: 20px; padding: 7px 13px;
  background: var(--bg-raise); transition: color 120ms ease, border-color 120ms ease;
}
.jump a:hover { color: var(--accent-ink); border-color: color-mix(in srgb, var(--accent) 45%, var(--border)); }

.rr-list { display: grid; gap: 4px; }
.rr {
  display: flex; align-items: baseline; gap: 12px; text-decoration: none;
  padding: 9px 10px; border-radius: 8px;
  font: 500 14.5px/1.5 var(--sans); color: var(--ink);
  transition: background 120ms ease;
}
a.rr:hover { background: var(--accent-soft); }
a.rr:hover .rr-a { transform: translate(2px, -1px); }
.rr-t { color: var(--ink); }
.rr-t a { color: inherit; text-decoration: none; }
.rr-lead { color: var(--dim); font-weight: 450; }
.rr-d { margin-left: auto; font: 450 11px/1 var(--mono); color: var(--faint); white-space: nowrap; flex: none; }
.rr-a { font: 400 13px/1 var(--sans); color: var(--accent); flex: none; transition: transform 120ms ease; }
.rr-multi { flex-wrap: wrap; }
.rr-chips { display: flex; flex-wrap: wrap; gap: 6px; }
.rr-chip {
  font: 500 12.5px/1 var(--sans); color: var(--accent-ink); text-decoration: none;
  border: 1px solid color-mix(in srgb, var(--accent) 30%, var(--border));
  border-radius: 16px; padding: 6px 11px; background: var(--accent-soft);
}
.rr-chip:hover { border-color: var(--accent); }

/* concept chips (used by v2 sections) */
.chips { display: flex; flex-wrap: wrap; gap: 7px; }
.chip {
  font: 500 13px/1.45 var(--sans); color: var(--ink-soft);
  border: 1px solid var(--border-2); border-radius: 9px; padding: 6px 11px;
  background: var(--panel);
}
.chip code { font-size: 0.85em; background: none; border: 0; padding: 0; }
/* aside: de-emphasized source notes */
.aside-note {
  margin: 1.4em 0; padding: 12px 16px; border-left: 2px solid var(--border-2);
  font-family: var(--sans);
}
.aside-note .pk { color: var(--faint); margin-bottom: 7px; }
.aside-row { font: 450 12.5px/1.7 var(--sans); color: var(--dim); overflow-wrap: anywhere; }
.aside-row code { font-size: 0.9em; background: none; border: 0; padding: 0; color: var(--dim); }
.aside-row a { color: var(--dim); }

.mm-a { font: 650 17px/1.2 var(--mono); color: var(--accent-ink); }
.mm-eq { font: 400 17px/1 var(--mono); color: var(--faint); }
.mm-b { font: 650 17px/1.2 var(--mono); color: var(--ink); }

/* ---------- v2 style system (options 2 + 3 + 4) ---------- */

/* shared unboxed label */
.lb {
  font: 650 10.5px/1 var(--mono); letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--faint); margin-bottom: 10px;
}
.lb-acc { color: var(--ink-soft); }
.lb-warm { color: var(--warm); }
.sec { margin: 1.7em 0; font-family: var(--sans); }
.sec.is-dim .chip { color: var(--dim); background: transparent; border-style: dashed; }

/* unboxed read rows */
.sec-read .rr { padding: 9px 2px; border-bottom: 1px solid var(--border); border-radius: 0; }
.sec-read .rr:last-child { border-bottom: 0; }
.sec-read a.rr:hover { background: transparent; }
.sec-read a.rr:hover .rr-t { color: var(--accent-ink); }

/* unboxed generic list */
.ulist { list-style: none; display: grid; gap: 7px; }
.ulist li { position: relative; padding-left: 18px; font: 450 14.5px/1.55 var(--sans); color: var(--ink-soft); }
.ulist li::before { content: "·"; position: absolute; left: 3px; top: -2px; font-weight: 800; font-size: 19px; color: var(--faint); }

/* option 2: floating tag card */
.card2 {
  position: relative; margin: 2.2em 0 1.7em;
  border: 1px solid var(--border-2); border-radius: 16px;
  background: color-mix(in srgb, var(--panel) 55%, var(--bg-raise));
  padding: 26px 26px 20px; font-family: var(--sans);
}
.card2 .tag {
  position: absolute; top: 0; left: 22px; transform: translateY(-50%);
  font: 650 10.5px/1 var(--mono); letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--accent-ink); background: var(--bg);
  border: 1px solid var(--border-2); padding: 7px 12px; border-radius: 20px;
  white-space: nowrap;
}
.card2 .steps { list-style: none; counter-reset: n; display: grid; gap: 10px; }
.card2 .steps > li { counter-increment: n; position: relative; padding-left: 34px; font: 450 14.5px/1.55 var(--sans); color: var(--ink-soft); }
.card2 .steps > li::before {
  content: counter(n, decimal-leading-zero); position: absolute; left: 0; top: 1px;
  font: 600 11px/1.6 var(--mono); color: var(--accent);
}
.card2 .steps li ul { list-style: none; padding-left: 0; margin-top: 8px; display: grid; gap: 6px; }
.card2 .steps li ul li { position: relative; padding-left: 16px; }
.card2 .steps li ul li::before { content: "·"; position: absolute; left: 2px; font: 800 17px/1 var(--sans); color: var(--faint); }
.card2 .steps li pre { margin-top: 10px; }
.card2.gist2 ul { list-style: none; display: grid; gap: 9px; }
.card2.gist2 li { position: relative; padding-left: 22px; font: 450 15px/1.55 var(--sans); color: var(--ink-soft); }
.card2.gist2 li::before { content: "◆"; position: absolute; left: 0; top: 1px; font-size: 10px; color: var(--accent); }
.card2.gist2 li b { color: var(--ink); font-weight: 650; }
.card2.gist2 { margin-top: 1.2em; margin-bottom: 1.4em; }

/* option 3: blueprint corners */
.corners { position: relative; margin: 2.2em 0; padding: 28px 32px 22px; }
.corners .cx { position: absolute; width: 18px; height: 18px; border: 2px solid var(--warm); }
.corners .c1 { top: 0; left: 0; border-right: 0; border-bottom: 0; }
.corners .c2 { top: 0; right: 0; border-left: 0; border-bottom: 0; }
.corners .c3 { bottom: 0; left: 0; border-right: 0; border-top: 0; }
.corners .c4 { bottom: 0; right: 0; border-left: 0; border-top: 0; }
.corners .lb { margin-bottom: 14px; }
.corners .taste-item { font: italic 500 17px/1.6 var(--serif); color: var(--ink); max-width: 60ch; padding: 8px 0; }
.corners .taste-item + .taste-item { border-top: 1px dashed var(--border); }
.corners-mini { padding: 20px 32px; display: flex; justify-content: center; }
.corners-mini .cx { border-color: var(--accent); }
.mm2 { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.mm2 .mm-a { color: var(--accent-ink); }
.mm2 .mm-b { color: var(--ink); }

/* option 4: signal rows */
.sig .row {
  display: flex; gap: 12px; align-items: baseline; padding: 9px 2px;
  border-bottom: 1px solid var(--border); font: 450 14.5px/1.55 var(--sans); color: var(--ink-soft);
}
.sig .row:last-child { border-bottom: 0; }
.sig .ic {
  flex: none; width: 18px; height: 18px; border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  font: 700 10px/1 var(--sans); align-self: flex-start; margin-top: 2px;
}
.sig .ok .ic { color: var(--ok); background: color-mix(in srgb, var(--ok) 14%, transparent); }
.sig .no .ic { color: var(--warm); background: color-mix(in srgb, var(--warm) 14%, transparent); }
.sig .dim .ic { color: var(--faint); background: var(--panel); }
.sig .dim { color: var(--dim); }

/* ---------- version toggle (chapter 13) ---------- */
.version-toggle {
  display: inline-flex; border: 1px solid var(--border); border-radius: 11px;
  background: var(--panel); padding: 4px; gap: 4px; margin: 6px 0 26px;
  font-family: var(--sans);
}
.version-toggle button {
  border: 0; background: none; color: var(--dim); cursor: pointer;
  font: 600 13px/1 var(--sans); padding: 9px 18px; border-radius: 8px;
  display: inline-flex; align-items: center; gap: 8px;
  transition: background 130ms ease, color 130ms ease;
}
.version-toggle button .mins { font: 500 10.5px/1 var(--mono); color: var(--faint); }
.version-toggle button.active { background: var(--bg-raise); color: var(--ink); box-shadow: var(--shadow); }
.version-toggle button.active .mins { color: var(--accent); }
.version { display: none; }
.version.active { display: block; }
.detail-invite {
  margin-top: 3em; border: 1px dashed var(--border-2); border-radius: 13px;
  padding: 22px 26px; font-family: var(--sans); background: var(--panel);
}
.detail-invite .k { font: 600 10.5px/1 var(--mono); letter-spacing: 0.16em; text-transform: uppercase; color: var(--accent); }
.detail-invite p { font: 450 14.5px/1.6 var(--sans); color: var(--ink-soft); margin: 10px 0 14px; }
.detail-invite button {
  border: 1px solid var(--accent); color: var(--accent-ink); background: var(--accent-soft);
  font: 600 13px/1 var(--sans); padding: 10px 18px; border-radius: 9px; cursor: pointer;
}

/* ---------- further reading block ---------- */
.reads { margin-top: 2.6em; display: grid; gap: 14px; font-family: var(--sans); }
.read-card {
  border: 1px solid var(--border); border-radius: 13px; background: var(--bg-raise);
  padding: 20px 24px; box-shadow: var(--shadow); display: flex; gap: 18px;
  text-decoration: none; transition: transform 140ms ease, box-shadow 140ms ease, border-color 140ms ease;
}
.read-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lift); border-color: var(--border-2); }
.read-card .no { font: 700 13px/1.2 var(--mono); color: var(--accent); flex: none; padding-top: 3px; }
.read-card .no + span { min-width: 0; }
.read-card .rt { display: block; font: 650 16px/1.35 var(--sans); color: var(--ink); }
.read-card .ra { display: block; font: 500 12px/1.4 var(--mono); color: var(--dim); margin-top: 4px; }
.read-card .rb { display: block; font: 450 14px/1.6 var(--sans); color: var(--ink-soft); margin-top: 9px; max-width: 64ch; }
.read-card .rl { display: block; font: 500 11.5px/1.4 var(--mono); color: var(--accent-ink); margin-top: 10px; overflow-wrap: anywhere; }

/* ---------- next teaser ---------- */
.next-teaser {
  display: block; text-decoration: none; margin-top: 4em;
  border: 1px solid var(--border); border-radius: 16px;
  background: var(--bg-raise); box-shadow: var(--shadow);
  padding: 28px 32px; position: relative; overflow: hidden;
  transition: transform 150ms ease, box-shadow 150ms ease, border-color 150ms ease;
  font-family: var(--sans);
}
.next-teaser:hover { transform: translateY(-3px); box-shadow: var(--shadow-lift); border-color: color-mix(in srgb, var(--accent) 40%, var(--border)); }
.next-teaser::after {
  content: "→"; position: absolute; right: 30px; top: 50%; transform: translateY(-50%);
  font: 300 34px/1 var(--sans); color: var(--accent); opacity: 0.85;
  transition: transform 150ms ease;
}
.next-teaser:hover::after { transform: translate(6px, -50%); }
.next-teaser .k { font: 600 10.5px/1 var(--mono); letter-spacing: 0.18em; text-transform: uppercase; color: var(--accent); }
.next-teaser .t { display: block; font: 750 22px/1.25 var(--sans); letter-spacing: -0.015em; color: var(--ink); margin: 12px 0 9px; padding-right: 60px; }
.next-teaser .h { display: block; font: italic 400 15.5px/1.55 var(--serif); color: var(--dim); max-width: 56ch; padding-right: 60px; }
.next-teaser .pn { font: 500 11px/1 var(--mono); color: var(--faint); display: inline-block; margin-top: 14px; }
.next-teaser .pn:empty { display: none; }

/* ---------- landing ---------- */
.landing { max-width: 1060px; margin: 0 auto; padding: 72px 36px 90px; position: relative; z-index: 1; }
.hero { max-width: 780px; }
.hero .k { font: 600 11.5px/1 var(--mono); letter-spacing: 0.2em; text-transform: uppercase; color: var(--accent); }
.hero .updated { display: block; margin-top: 12px; font: 500 11px/1.3 var(--mono); color: var(--faint); }
.hero h1 {
  font: 800 clamp(42px, 6.4vw, 72px)/1.02 var(--sans); letter-spacing: -0.034em;
  margin: 22px 0 10px; color: var(--ink);
}
.hero .sub {
  font: 400 clamp(20px, 2.6vw, 26px)/1.35 var(--serif); font-style: italic;
  color: var(--ink-soft); margin-bottom: 26px;
}
.hero .premise { font: 400 17.5px/1.7 var(--serif); color: var(--ink-soft); max-width: 62ch; }
.thesis {
  margin: 40px 0 8px; border-left: 3px solid var(--accent); padding: 8px 0 8px 28px;
  font: italic 500 clamp(22px, 3vw, 27px)/1.45 var(--serif); color: var(--ink); max-width: 30em;
}
.hero-plate { margin: 48px auto 0; max-width: 720px; }
.hero-plate .frame { background: var(--plate-bg); border: 1px solid var(--border); border-radius: 16px; padding: 16px; box-shadow: var(--shadow-lift); }
.hero-plate.hero-diagram { max-width: 860px; }
.hero-plate.hero-diagram .frame { background: var(--bg-raise); padding: 26px 22px; }
.hero-plate img { display: block; width: 100%; height: auto; border-radius: 10px; }

.sec-kick { font: 600 11px/1 var(--mono); letter-spacing: 0.18em; text-transform: uppercase; color: var(--accent); margin: 72px 0 0; }
.sec-title { font: 750 clamp(26px, 3.4vw, 34px)/1.15 var(--sans); letter-spacing: -0.022em; margin: 14px 0 10px; color: var(--ink); }
.sec-sub { font: 400 17px/1.6 var(--serif); color: var(--dim); max-width: 60ch; }

.paths-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(310px, 1fr)); gap: 16px; margin-top: 30px; }
.path-card {
  text-align: left; border: 1px solid var(--border); border-radius: 15px;
  background: var(--bg-raise); box-shadow: var(--shadow); cursor: pointer;
  padding: 24px 26px 20px; font-family: var(--sans); color: var(--ink);
  transition: transform 150ms ease, box-shadow 150ms ease, border-color 150ms ease;
  display: flex; flex-direction: column; gap: 0;
}
.path-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lift); border-color: color-mix(in srgb, var(--accent) 45%, var(--border)); }
.path-card.active-path { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent), var(--shadow-lift); }
.path-card .pk { font: 600 10px/1 var(--mono); letter-spacing: 0.16em; text-transform: uppercase; color: var(--accent); display: flex; justify-content: space-between; }
.path-card .pk .len { color: var(--faint); letter-spacing: 0.06em; }
.path-card h3 { font: 720 19px/1.25 var(--sans); letter-spacing: -0.015em; margin: 12px 0 7px; }
.path-card .who { font: italic 400 14.5px/1.5 var(--serif); color: var(--ink-soft); }
.path-card .blurb { font: 450 13px/1.6 var(--sans); color: var(--dim); margin-top: 9px; }
.path-card .stops { display: flex; flex-wrap: wrap; gap: 5px; margin-top: 16px; }
.path-card .stops span {
  font: 600 10.5px/1 var(--mono); color: var(--dim);
  border: 1px solid var(--border-2); border-radius: 6px; padding: 4px 7px;
  background: var(--panel);
}
.path-card .stops span.read { color: var(--ok); border-color: color-mix(in srgb, var(--ok) 50%, var(--border-2)); }
.path-card .go { margin-top: 16px; font: 650 12.5px/1 var(--sans); color: var(--accent-ink); }

.hero-cta { margin-top: 30px; }
.paths-list { margin-top: 18px; display: grid; gap: 10px; }
.path-card.path-row { display: flex; flex-direction: row; align-items: center; gap: 18px; text-align: left; padding: 14px 18px; }
.path-card.path-row:hover { transform: none; }
.path-card.path-row .pr-name { font: 600 11px/1.3 var(--mono); letter-spacing: 0.14em; text-transform: uppercase; color: var(--accent); flex: none; width: 150px; }
.path-card.path-row .pr-who { font: italic 400 14px/1.45 var(--serif); color: var(--ink-soft); flex: 1; min-width: 0; }
.path-card.path-row .go { margin-top: 0; flex: none; }
@media (max-width: 720px) {
  .path-card.path-row { flex-wrap: wrap; gap: 10px; }
  .path-card.path-row .pr-name { width: 100%; }
  .path-card.path-row .pr-who { flex: 1 1 100%; min-width: 100%; }
}

.toc { margin-top: 30px; display: grid; gap: 34px; }
.toc-part .ph { font: 600 11px/1 var(--mono); letter-spacing: 0.16em; text-transform: uppercase; color: var(--faint); padding-bottom: 4px; }
.toc-item {
  display: flex; gap: 20px; align-items: baseline; text-decoration: none;
  padding: 15px 14px; margin: 0 -14px; border-radius: 12px; border-bottom: 1px solid var(--border);
  transition: background 130ms ease;
}
.toc-item:hover { background: var(--accent-soft); border-bottom-color: transparent; }
.toc-item .no { font: 600 12.5px/1 var(--mono); color: var(--accent); width: 26px; flex: none; }
.toc-item .tt { font: 650 17.5px/1.3 var(--sans); letter-spacing: -0.012em; color: var(--ink); }
.toc-item .hk { display: block; font: italic 400 14px/1.5 var(--serif); color: var(--dim); margin-top: 5px; max-width: 62ch; }
.toc-item .mins { margin-left: auto; font: 500 11px/1 var(--mono); color: var(--faint); flex: none; display: flex; align-items: center; gap: 8px; }
.toc-item .rdot { display: none; width: 6px; height: 6px; border-radius: 50%; }
.toc-item.is-read .rdot { display: inline-block; background: var(--ok); }

.land-foot { margin-top: 70px; display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 10px; text-decoration: none; cursor: pointer;
  font: 650 14px/1 var(--sans); padding: 14px 24px; border-radius: 11px;
  transition: transform 130ms ease, box-shadow 130ms ease;
}
.btn:hover { transform: translateY(-2px); box-shadow: var(--shadow-lift); }
.btn-primary { background: var(--accent); color: #fff; border: 1px solid var(--accent); }
[data-theme="dark"] .btn-primary { color: #0b0f19; }
.btn-ghost { border: 1px solid var(--border-2); color: var(--ink); background: var(--bg-raise); }

/* ---------- sans body pilot ----------
   Body paragraphs in Inter for readability. Serif survives only as
   editorial accent: standfirst, pull quotes, and taste items. */
.font-sans .prose { font-size: 17px; line-height: 1.75; font-family: var(--sans); }
.font-sans .prose p, .font-sans .prose ul, .font-sans .prose ol { font-weight: 450; letter-spacing: 0.001em; color: var(--ink-soft); }
.font-sans .prose p { max-width: 68ch; }
.font-sans .prose strong { color: var(--ink); }
.font-sans .prose blockquote { font-family: var(--serif); }
.font-sans .prose code { font-size: 0.82em; }

/* ---------- reveal animation ---------- */
@media (prefers-reduced-motion: no-preference) {
  .reveal { opacity: 0; transform: translateY(14px); transition: opacity 500ms ease, transform 500ms ease; }
  .reveal.in { opacity: 1; transform: none; }
}

/* ---------- responsive ---------- */
@media (max-width: 1080px) {
  .shell { display: block; }
  .topbar {
    display: flex; position: sticky; top: 0; z-index: 150;
    align-items: center; gap: 14px; padding: 12px 18px;
    background: color-mix(in srgb, var(--bg) 88%, transparent);
    backdrop-filter: blur(10px); border-bottom: 1px solid var(--border);
    font-family: var(--sans);
  }
  .topbar .menu-btn {
    border: 1px solid var(--border-2); background: var(--bg-raise); color: var(--ink);
    border-radius: 8px; padding: 7px 12px; font: 600 12px/1 var(--sans); cursor: pointer;
  }
  .topbar .tb-title { font: 700 13px/1.3 var(--sans); color: var(--ink); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
  .sidebar {
    position: fixed; left: 0; top: 0; bottom: 0; z-index: 300; height: 100dvh;
    transform: translateX(-102%); transition: transform 220ms ease;
    box-shadow: var(--shadow-lift); width: min(320px, 86vw);
  }
  .sidebar.open { transform: none; }
  .scrim { display: block; position: fixed; inset: 0; z-index: 250; background: rgba(8, 10, 18, 0.45); opacity: 0; pointer-events: none; transition: opacity 200ms ease; }
  .scrim.show { opacity: 1; pointer-events: auto; }
  figure.plate { margin-left: -10px; margin-right: -10px; }
  .article { padding: 40px 22px 70px; }
  .ch-head .bignum { display: none; }
  .prose { font-size: 18px; }
}
@media (max-width: 640px) {
  figure.plate { margin-left: -8px; margin-right: -8px; }
  .prose pre { padding: 16px 18px; font-size: 13px; }
  .landing { padding: 48px 22px 70px; }
}


/* Shared consulting-site return link. */
.consulting-return {
  position: fixed;
  z-index: 220;
  right: 18px;
  top: 14px;
  display: inline-flex;
  gap: 8px;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 8px 11px;
  color: var(--ink);
  background: color-mix(in srgb, var(--bg-raise) 88%, transparent);
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
  font: 650 10px/1 var(--sans);
  text-decoration: none;
}
.consulting-return span { color: var(--accent-ink); font-weight: 500; }
.consulting-return:hover { border-color: var(--border-2); text-decoration: none; }
@media (max-width: 720px) {
  .consulting-return { right: 10px; top: 10px; }
  .consulting-return span { display: none; }
}