:root {
  --paper: #f8fbff;
  --paper-warm: #fffaf0;
  --surface: #ffffff;
  --ink: #142b4a;
  --soft-ink: #38506f;
  --line: #c8d9ed;
  --line-strong: #8da9c9;
  --amber: #ffb000;
  --amber-text: #995300;
  --amber-wash: #fff1c7;
  --teal: #10a7a1;
  --teal-text: #0b7775;
  --teal-wash: #dff8f5;
  --magenta: #cc3f75;
  --magenta-text: #a32e5b;
  --magenta-wash: #fde6ef;
  --blue: #4777b8;
  --blue-wash: #eaf3ff;
  --violet: #7559a9;
  --violet-wash: #f0ebfb;
  --green: #197851;
  --red: #a83a3a;
  --shadow: 0 20px 60px rgba(20, 43, 74, .11);
  --shadow-soft: 0 9px 30px rgba(20, 43, 74, .075);
  --serif: Georgia, "Times New Roman", serif;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    linear-gradient(rgba(71, 119, 184, .065) 1px, transparent 1px),
    linear-gradient(90deg, rgba(71, 119, 184, .065) 1px, transparent 1px),
    var(--paper);
  background-size: 28px 28px;
  font-family: var(--sans);
  line-height: 1.62;
  text-rendering: optimizeLegibility;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(circle at 78% 7%, rgba(255, 176, 0, .12), transparent 28rem),
    radial-gradient(circle at 12% 54%, rgba(16, 167, 161, .09), transparent 32rem),
    radial-gradient(circle at 90% 82%, rgba(204, 63, 117, .07), transparent 28rem);
}
a { color: inherit; }
button, input { font: inherit; }
button { color: inherit; }
h1, h2, h3, p { margin-top: 0; }
::selection { background: var(--amber-wash); }

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 1000;
  padding: .7rem 1rem;
  color: white;
  background: var(--ink);
  transform: translateY(-160%);
  transition: transform .2s ease;
}
.skip-link:focus { transform: none; }
.noscript { padding: 2rem; }

.progress-rail {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 200;
  height: 4px;
  background: transparent;
}
.progress-rail__fill {
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--amber), var(--teal), var(--magenta), var(--blue));
  transform: scaleX(0);
  transform-origin: left center;
}

.site-nav {
  position: relative;
  z-index: 20;
  width: min(1280px, calc(100% - 40px));
  min-height: 76px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  border-bottom: 1px solid rgba(141, 169, 201, .55);
}
.brand, .nav-back {
  display: inline-flex;
  align-items: center;
  gap: .78rem;
  color: var(--ink);
  text-decoration: none;
  font-weight: 800;
  letter-spacing: -.02em;
}
.brand-mark {
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  border-radius: 12px 12px 4px 12px;
  color: #fffaf0;
  background: var(--ink);
  box-shadow: -4px 4px 0 var(--amber);
  font: 500 1.35rem/1 var(--serif);
}
.nav-actions { display: flex; align-items: center; gap: .55rem; }
.nav-back, .motion-button {
  min-height: 40px;
  padding: .55rem .78rem;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  background: rgba(255, 255, 255, .72);
  cursor: pointer;
  font-size: .82rem;
  transition: transform .2s, background .2s, border-color .2s;
}
.nav-back:hover, .nav-back:focus-visible,
.motion-button:hover, .motion-button:focus-visible {
  background: white;
  border-color: var(--ink);
  transform: translateY(-1px);
  outline: none;
}

.hero {
  width: min(1280px, calc(100% - 40px));
  min-height: calc(100svh - 76px);
  margin: 0 auto;
  padding: clamp(4rem, 9vh, 8rem) 0 clamp(5rem, 10vh, 9rem);
  display: grid;
  grid-template-columns: minmax(0, .9fr) minmax(440px, 1.1fr);
  align-items: center;
  gap: clamp(2rem, 6vw, 6rem);
}
.eyebrow, .section-kicker {
  margin: 0 0 1rem;
  color: var(--teal-text);
  font-size: .76rem;
  font-weight: 850;
  letter-spacing: .17em;
  text-transform: uppercase;
}
h1 {
  margin-bottom: 1.6rem;
  max-width: 760px;
  font: 500 clamp(3.7rem, 7.4vw, 7.9rem)/.9 var(--serif);
  letter-spacing: -.065em;
}
.hero-emphasis {
  display: inline-block;
  color: var(--magenta-text);
  font-style: italic;
}
.hero-lede {
  max-width: 660px;
  margin-bottom: 0;
  color: var(--soft-ink);
  font: 400 clamp(1.08rem, 1.8vw, 1.38rem)/1.5 var(--serif);
}
.hero-actions { display: flex; flex-wrap: wrap; gap: .7rem; margin-top: 2rem; }
.primary-cta, .secondary-cta {
  min-height: 48px;
  padding: .8rem 1.05rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  font-weight: 800;
  text-decoration: none;
}
.primary-cta { color: white; background: var(--ink); }
.secondary-cta { border: 1px solid var(--line-strong); background: rgba(255, 255, 255, .66); }
.hero-aside {
  margin-top: 2rem;
  padding-left: 1rem;
  border-left: 3px solid var(--amber);
  color: var(--soft-ink);
  font-size: .86rem;
}

.braid-stage {
  position: relative;
  min-height: 600px;
  display: grid;
  place-items: center;
}
.braid-frame {
  position: relative;
  width: min(100%, 650px);
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 28px;
  background: rgba(255, 255, 255, .76);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.braid-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(110deg, rgba(255,176,0,.07), transparent 35%),
    linear-gradient(300deg, rgba(16,167,161,.08), transparent 40%);
  pointer-events: none;
}
.braid-map { position: relative; width: 100%; height: auto; display: block; }
.braid-map text { fill: var(--ink); font-family: var(--sans); }
.braid-map .map-label { font-size: 13px; font-weight: 800; }
.braid-map .map-small { font-size: 10px; fill: var(--soft-ink); letter-spacing: .07em; text-transform: uppercase; }
.braid-map .path {
  fill: none;
  stroke-width: 5;
  stroke-linecap: round;
  stroke-linejoin: round;
  opacity: .95;
}
.braid-map .path.infrastructure { stroke: var(--amber); }
.braid-map .path.logic { stroke: var(--teal); }
.braid-map .path.algebra { stroke: var(--magenta); }
.braid-map .path.machine { stroke: var(--blue); }
.braid-map .node { fill: white; stroke-width: 3; }
.braid-map .node.infrastructure { stroke: var(--amber); }
.braid-map .node.logic { stroke: var(--teal); }
.braid-map .node.algebra { stroke: var(--magenta); }
.braid-map .node.machine { stroke: var(--blue); }
.braid-legend {
  position: relative;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: .6rem 1rem;
  padding: .65rem .65rem .35rem;
  color: var(--soft-ink);
  font-size: .76rem;
}
.braid-legend span { display: flex; align-items: center; gap: .5rem; }
.braid-legend i { width: 24px; height: 4px; border-radius: 99px; }
.legend-infrastructure { background: var(--amber); }
.legend-logic { background: var(--teal); }
.legend-algebra { background: var(--magenta); }
.legend-machine { background: var(--blue); }

.thesis {
  width: min(1100px, calc(100% - 40px));
  margin: 0 auto clamp(7rem, 13vw, 12rem);
}
.thesis-grid {
  display: grid;
  grid-template-columns: .7fr 1.3fr;
  gap: clamp(2rem, 7vw, 7rem);
  padding: clamp(2rem, 5vw, 4rem);
  border: 1px solid var(--line-strong);
  border-radius: 18px 18px 4px 18px;
  background: rgba(255, 255, 255, .82);
  box-shadow: -8px 8px 0 var(--amber);
}
.thesis-title {
  font: 500 clamp(2.1rem, 4vw, 4.25rem)/1 var(--serif);
  letter-spacing: -.045em;
}
.thesis-copy p { color: var(--soft-ink); font-size: 1.02rem; }
.thesis-copy p:last-child { margin-bottom: 0; }
.thesis-rule {
  margin: 1.4rem 0 0;
  padding: 1rem 1.1rem;
  border-left: 4px solid var(--teal);
  background: var(--teal-wash);
  color: var(--ink) !important;
  font-weight: 700;
}

.timeline-intro {
  width: min(1280px, calc(100% - 40px));
  margin: 0 auto 2rem;
  display: grid;
  grid-template-columns: 1fr minmax(280px, .7fr);
  gap: 2rem;
  align-items: end;
}
.timeline-intro h2 {
  margin-bottom: 0;
  max-width: 900px;
  font: 500 clamp(2.9rem, 6vw, 6rem)/.96 var(--serif);
  letter-spacing: -.052em;
}
.timeline-intro p { margin: 0; color: var(--soft-ink); }

.navigator {
  position: sticky;
  top: 0;
  z-index: 100;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--paper) 92%, transparent);
  backdrop-filter: blur(16px);
}
.navigator__inner {
  width: min(1280px, calc(100% - 40px));
  min-height: 72px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.3rem;
}
.active-era {
  min-width: 210px;
  padding-left: .8rem;
  border-left: 3px solid var(--amber);
}
.active-era small { display: block; color: var(--soft-ink); font-size: .66rem; font-weight: 850; letter-spacing: .12em; text-transform: uppercase; }
.active-era strong { display: block; font: 500 1.05rem/1.2 var(--serif); }
.filters { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: .42rem; }
.filter-button {
  min-height: 38px;
  padding: .47rem .68rem;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: white;
  cursor: pointer;
  font-size: .73rem;
  font-weight: 750;
  transition: transform .2s, background .2s, border-color .2s;
}
.filter-button:hover, .filter-button:focus-visible { border-color: var(--ink); transform: translateY(-1px); outline: none; }
.filter-button[aria-pressed="true"] { color: white; border-color: var(--ink); background: var(--ink); }
.filter-count { color: var(--soft-ink); font: 600 .7rem/1 var(--mono); white-space: nowrap; }

.timeline { width: min(1280px, calc(100% - 40px)); margin: 0 auto; padding-bottom: 6rem; }
.era {
  --era-accent: var(--teal);
  position: relative;
  padding: clamp(6rem, 11vw, 11rem) 0 1rem;
  scroll-margin-top: 80px;
}
.era[hidden] { display: none; }
.era::before {
  content: attr(data-number);
  position: absolute;
  right: 0;
  top: clamp(3rem, 6vw, 6rem);
  color: color-mix(in srgb, var(--era-accent) 10%, transparent);
  font: 500 clamp(8rem, 22vw, 19rem)/.8 var(--serif);
  pointer-events: none;
}
.era-head {
  position: relative;
  max-width: 960px;
  margin-bottom: 4rem;
  display: grid;
  grid-template-columns: 150px 1fr;
  gap: clamp(1.5rem, 4vw, 4rem);
}
.era-range { color: var(--era-accent); font: 800 .76rem/1.35 var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.era-title { margin-bottom: .9rem; font: 500 clamp(2.5rem, 5vw, 5.4rem)/.96 var(--serif); letter-spacing: -.05em; }
.era-thesis { max-width: 760px; margin: 0; color: var(--soft-ink); font-size: 1.07rem; }
.era-question {
  display: inline-block;
  margin-top: 1.2rem;
  padding: .55rem .72rem;
  border-radius: 4px 12px 12px 12px;
  color: var(--ink);
  background: color-mix(in srgb, var(--era-accent) 12%, white);
  font-weight: 800;
  font-size: .78rem;
}
.events {
  position: relative;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.25rem;
}
.events::before {
  content: "";
  position: absolute;
  left: 50%;
  top: -1rem;
  bottom: -1rem;
  width: 1px;
  background: linear-gradient(transparent, var(--line), var(--line), transparent);
}
.event-card {
  --lane: var(--teal);
  position: relative;
  min-height: 100%;
  padding: 1.45rem 1.45rem 1.3rem 1.7rem;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(255, 255, 255, .9);
  box-shadow: var(--shadow-soft);
  overflow: hidden;
  transition: transform .25s, border-color .25s, box-shadow .25s, opacity .2s;
}
.event-card::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 6px;
  background: var(--lane);
}
.event-card::after {
  content: "";
  position: absolute;
  width: 125px;
  height: 125px;
  right: -72px;
  top: -72px;
  border-radius: 50%;
  background: color-mix(in srgb, var(--lane) 10%, transparent);
  pointer-events: none;
}
.event-card:hover { transform: translateY(-3px); border-color: var(--lane); box-shadow: var(--shadow); }
.event-card[hidden] { display: none; }
.event-topline { display: flex; align-items: flex-start; justify-content: space-between; gap: .8rem; }
.event-date { color: var(--lane); font: 850 .78rem/1.35 var(--mono); letter-spacing: .06em; }
.evidence {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .3rem .48rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--soft-ink);
  background: var(--paper);
  font-size: .63rem;
  font-weight: 800;
  line-height: 1;
  letter-spacing: .05em;
  text-transform: uppercase;
  white-space: nowrap;
}
.evidence::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--green); }
.evidence.independent::before { background: var(--violet); }
.evidence.uncertain::before { background: var(--amber-text); }
.event-card h3 { margin: .78rem 0 .35rem; font: 500 clamp(1.65rem, 2.8vw, 2.55rem)/1.04 var(--serif); letter-spacing: -.035em; }
.event-work { margin-bottom: 1rem; color: var(--soft-ink); font-size: .82rem; font-style: italic; }
.event-summary { color: #263f61; font-size: .94rem; }
.change-grid { display: grid; grid-template-columns: 1fr 1fr; gap: .75rem; margin-top: 1.2rem; }
.change {
  padding: .8rem;
  border-radius: 10px;
  background: color-mix(in srgb, var(--lane) 7%, white);
  font-size: .78rem;
  line-height: 1.45;
}
.change strong { display: block; margin-bottom: .2rem; color: var(--lane); font-size: .62rem; letter-spacing: .1em; text-transform: uppercase; }
.event-caveat {
  margin-top: 1rem;
  padding: .75rem .85rem;
  border-left: 3px solid var(--amber);
  background: var(--paper-warm);
  color: var(--soft-ink);
  font-size: .76rem;
}
.event-footer { margin-top: 1.1rem; padding-top: .9rem; border-top: 1px solid var(--line); display: flex; align-items: center; justify-content: space-between; gap: .8rem; }
.lane-label { display: flex; flex-wrap: wrap; gap: .35rem; }
.lane-tag { color: var(--soft-ink); font: 750 .62rem/1.2 var(--mono); letter-spacing: .06em; text-transform: uppercase; }
.source-link { color: var(--ink); font-size: .72rem; font-weight: 850; text-decoration: none; white-space: nowrap; }
.source-link:hover, .source-link:focus-visible { color: var(--lane); text-decoration: underline; outline: none; }

.hinge {
  position: relative;
  margin-top: clamp(6rem, 10vw, 10rem);
  padding: clamp(5rem, 10vw, 10rem) max(20px, calc((100vw - 1280px) / 2));
  color: white;
  background: var(--ink);
  overflow: hidden;
}
.hinge::before {
  content: "x² = x";
  position: absolute;
  top: -5rem;
  right: -1rem;
  color: rgba(255, 255, 255, .035);
  font: 500 clamp(12rem, 28vw, 30rem)/1 var(--serif);
  white-space: nowrap;
}
.hinge-grid { position: relative; display: grid; grid-template-columns: .72fr 1.28fr; gap: clamp(2rem, 8vw, 8rem); }
.hinge h2 { margin: 0; font: 500 clamp(3rem, 6.5vw, 7rem)/.93 var(--serif); letter-spacing: -.055em; }
.hinge-eyebrow { color: #ffc044; }
.hinge-copy { align-self: end; }
.hinge-copy p { color: #cfdded; font-size: 1.05rem; }
.hinge-equation { margin: 1.6rem 0; padding: 1.1rem; border-left: 4px solid var(--amber); background: rgba(255,255,255,.07); font: 500 clamp(1.4rem, 3.2vw, 3rem)/1.25 var(--serif); }
.hinge-chain { display: flex; flex-wrap: wrap; align-items: center; gap: .5rem; color: #cfdded; font-size: .76rem; font-weight: 800; letter-spacing: .05em; text-transform: uppercase; }
.hinge-chain span { padding: .45rem .55rem; border: 1px solid rgba(255,255,255,.2); border-radius: 7px; }
.hinge-chain i { color: var(--amber); font-style: normal; }

.fork-section {
  width: min(1180px, calc(100% - 40px));
  margin: clamp(7rem, 13vw, 13rem) auto;
}
.fork-section h2 { max-width: 900px; font: 500 clamp(2.8rem, 5.8vw, 5.7rem)/.98 var(--serif); letter-spacing: -.05em; }
.fork-lede { max-width: 780px; color: var(--soft-ink); font-size: 1.05rem; }
.fork-map {
  position: relative;
  margin-top: 3rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(1rem, 4vw, 3rem);
}
.fork-map::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 2rem;
  bottom: -2rem;
  width: 1px;
  background: var(--line-strong);
}
.fork-card { position: relative; padding: 1.6rem; border: 1px solid var(--line); border-radius: 18px; background: white; box-shadow: var(--shadow-soft); }
.fork-card.symbolic { border-top: 6px solid var(--teal); }
.fork-card.neural { border-top: 6px solid var(--magenta); }
.fork-card h3 { font: 500 2rem/1 var(--serif); }
.fork-card ul { padding-left: 1.1rem; color: var(--soft-ink); }
.reunion {
  position: relative;
  width: min(760px, 92%);
  margin: 4rem auto 0;
  padding: 1.7rem;
  border-radius: 18px 18px 4px 18px;
  color: white;
  background: var(--ink);
  box-shadow: -7px 7px 0 var(--amber);
  text-align: center;
}
.reunion::before, .reunion::after { content: ""; position: absolute; top: -4rem; width: 38%; height: 4rem; border-bottom: 2px solid var(--amber); }
.reunion::before { left: 11%; border-left: 2px solid var(--teal); border-radius: 0 0 0 20px; }
.reunion::after { right: 11%; border-right: 2px solid var(--magenta); border-radius: 0 0 20px 0; }
.reunion h3 { margin-bottom: .55rem; font: 500 2rem/1.1 var(--serif); }
.reunion p { margin: 0; color: #cfdded; }

.myths {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto clamp(7rem, 12vw, 12rem);
}
.myths h2, .sources h2 { font: 500 clamp(2.5rem, 5vw, 4.8rem)/1 var(--serif); letter-spacing: -.045em; }
.myth-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; }
.myth-card { padding: 1.35rem; border: 1px solid var(--line); border-radius: 14px; background: rgba(255,255,255,.82); }
.myth-card del { display: block; margin-bottom: .65rem; color: var(--red); font: 500 1.2rem/1.25 var(--serif); text-decoration-thickness: 2px; }
.myth-card p { margin: 0; color: var(--soft-ink); font-size: .9rem; }

.sources {
  width: min(1280px, calc(100% - 40px));
  margin: 0 auto;
  padding: 0 0 8rem;
}
.sources-intro { max-width: 760px; color: var(--soft-ink); }
.source-grid { margin-top: 2.2rem; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .9rem; }
.source-card {
  min-height: 165px;
  padding: 1.1rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255,255,255,.82);
  text-decoration: none;
  transition: transform .2s, border-color .2s, background .2s;
}
.source-card:hover, .source-card:focus-visible { transform: translateY(-3px); border-color: var(--ink); background: white; outline: none; }
.source-card small { color: var(--teal-text); font-size: .66rem; font-weight: 850; letter-spacing: .1em; text-transform: uppercase; }
.source-card strong { display: block; margin-top: .55rem; font: 500 1.05rem/1.25 var(--serif); }
.source-card span { color: var(--soft-ink); font-size: .72rem; }

footer { padding: 2.2rem 20px; color: #d9e5f3; background: var(--ink); text-align: center; font-size: .8rem; }
footer a { color: white; }

@media (max-width: 1040px) {
  .hero { grid-template-columns: 1fr; }
  .hero-copy { max-width: 850px; }
  .braid-stage { min-height: 0; }
  .braid-frame { max-width: 760px; }
  .timeline-intro { grid-template-columns: 1fr; }
  .navigator__inner { min-height: 84px; }
  .active-era { display: none; }
  .filters { justify-content: flex-start; }
  .source-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  .site-nav, .hero, .timeline-intro, .timeline, .navigator__inner, .sources { width: min(100% - 24px, 1280px); }
  .brand-name, .motion-button { display: none; }
  .hero { padding-top: 4.5rem; }
  h1 { font-size: clamp(3.45rem, 16vw, 6rem); }
  .thesis { width: min(100% - 24px, 1100px); }
  .thesis-grid { grid-template-columns: 1fr; padding: 1.4rem; }
  .braid-frame { padding: .5rem; border-radius: 18px; }
  .braid-map .map-label { font-size: 16px; }
  .braid-map .map-small { font-size: 12px; }
  .navigator { position: relative; }
  .navigator__inner { padding: .75rem 0; display: block; }
  .filters { gap: .35rem; }
  .filter-count { display: block; margin-top: .7rem; }
  .era { padding-top: 6rem; }
  .era-head { grid-template-columns: 1fr; gap: .7rem; }
  .events { grid-template-columns: 1fr; }
  .events::before { display: none; }
  .change-grid { grid-template-columns: 1fr; }
  .hinge-grid, .fork-map { grid-template-columns: 1fr; }
  .fork-map::before { display: none; }
  .reunion::before, .reunion::after { display: none; }
  .myth-grid, .source-grid { grid-template-columns: 1fr; }
}

@media (max-width: 440px) {
  .nav-back span { display: none; }
  .braid-legend { grid-template-columns: 1fr; }
  .event-card { padding: 1.2rem 1rem 1.1rem 1.35rem; }
  .event-topline, .event-footer { align-items: flex-start; flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}