:root {
  color-scheme: dark;
  --ink: #edf3e9;
  --muted: #9ca899;
  --paper: #10140f;
  --paper-raised: #171d16;
  --paper-soft: #20281e;
  --line: rgba(212, 230, 203, 0.17);
  --accent: #c7f36b;
  --accent-strong: #a7df3c;
  --signal: #ff825f;
  --shadow: rgba(0, 0, 0, 0.34);
  --display: Georgia, "Times New Roman", serif;
  --sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

html[data-theme="light"] {
  color-scheme: light;
  --ink: #182014;
  --muted: #5d6859;
  --paper: #f3f1e8;
  --paper-raised: #fbfaf4;
  --paper-soft: #e4e7d8;
  --line: rgba(31, 48, 23, 0.17);
  --accent: #568900;
  --accent-strong: #477400;
  --signal: #bd3f24;
  --shadow: rgba(40, 48, 34, 0.12);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.55;
  overflow-x: hidden;
}

button, input { font: inherit; }
a { color: inherit; }
code { font-family: var(--mono); }

.grain {
  position: fixed;
  inset: 0;
  z-index: 10;
  pointer-events: none;
  opacity: .055;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.65'/%3E%3C/svg%3E");
}

.skip-link {
  position: fixed;
  top: .75rem;
  left: .75rem;
  z-index: 30;
  padding: .65rem .9rem;
  color: #10140f;
  background: var(--accent);
  transform: translateY(-180%);
}
.skip-link:focus { transform: translateY(0); }

.topbar {
  position: sticky;
  top: 0;
  z-index: 8;
  display: flex;
  align-items: center;
  gap: 2rem;
  min-height: 4.25rem;
  padding: 0 clamp(1.1rem, 4vw, 4rem);
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(18px);
}
.brand {
  margin-right: auto;
  font-family: var(--mono);
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .12em;
  text-decoration: none;
}
.brand span { color: var(--accent); }
.topbar nav { display: flex; gap: 1.3rem; }
.topbar nav a {
  color: var(--muted);
  font-size: .74rem;
  font-weight: 650;
  letter-spacing: .08em;
  text-decoration: none;
  text-transform: uppercase;
}
.topbar nav a:hover { color: var(--ink); }
.icon-button {
  width: 2.35rem;
  height: 2.35rem;
  border: 1px solid var(--line);
  border-radius: 50%;
  color: var(--ink);
  background: transparent;
  cursor: pointer;
}

.hero, .section, footer { padding-inline: clamp(1.2rem, 5.5vw, 6rem); }
.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(18rem, .85fr);
  gap: 4rem;
  min-height: calc(100svh - 4.25rem);
  padding-block: clamp(5rem, 10vw, 9rem) 2.5rem;
  border-bottom: 1px solid var(--line);
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  right: 7%;
  top: 16%;
  width: 30rem;
  height: 30rem;
  border-radius: 50%;
  background: color-mix(in srgb, var(--accent) 11%, transparent);
  filter: blur(90px);
  pointer-events: none;
}
.eyebrow {
  margin: 0 0 1rem;
  color: var(--accent);
  font-family: var(--mono);
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .15em;
  text-transform: uppercase;
}
.hero h1, .section-heading h2, .concept h2 {
  margin: 0;
  font-family: var(--display);
  font-weight: 400;
  line-height: .98;
  letter-spacing: -.045em;
}
.hero h1 { max-width: 13ch; font-size: clamp(3.6rem, 7.5vw, 7.3rem); }
.hero h1 em { color: var(--accent); font-weight: 400; }
.lede { max-width: 42rem; margin: 2rem 0; color: var(--muted); font-size: clamp(1rem, 1.5vw, 1.22rem); }
.hero-actions { display: flex; flex-wrap: wrap; gap: .7rem; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.8rem;
  padding: .72rem 1rem;
  border: 1px solid var(--line);
  border-radius: .2rem;
  color: var(--ink);
  background: var(--paper-raised);
  font-family: var(--mono);
  font-size: .74rem;
  font-weight: 700;
  letter-spacing: .04em;
  text-decoration: none;
  cursor: pointer;
}
.button:hover { border-color: var(--accent); }
.button.primary { border-color: var(--accent); color: #10140f; background: var(--accent); }
.button.primary:hover { background: var(--accent-strong); }
.button.ghost { background: transparent; }

.hero-machine { position: relative; align-self: center; aspect-ratio: 1; max-width: 31rem; width: 100%; margin-inline: auto; }
.machine-ring { position: absolute; inset: 10%; border: 1px solid var(--line); border-radius: 50%; }
.machine-ring::before, .machine-ring::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: .45rem;
  height: .45rem;
  margin: -.225rem;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 1rem var(--accent);
}
.machine-ring::before { transform: rotate(25deg) translateX(13.6rem); }
.machine-ring::after { transform: rotate(205deg) translateX(13.6rem); }
.ring-two { inset: 23%; border-style: dashed; animation: orbit 36s linear infinite; }
.ring-two::before { transform: rotate(105deg) translateX(8.8rem); background: var(--signal); }
.ring-two::after { transform: rotate(285deg) translateX(8.8rem); background: var(--signal); }
.machine-core {
  position: absolute;
  inset: 34%;
  display: grid;
  place-content: center;
  text-align: center;
  border: 1px solid var(--accent);
  border-radius: 50%;
  background: var(--paper-raised);
  box-shadow: 0 0 5rem color-mix(in srgb, var(--accent) 13%, transparent);
}
.machine-core small, .machine-core span { font: 700 .58rem/1 var(--mono); letter-spacing: .12em; }
.machine-core strong { font: 400 clamp(3rem, 7vw, 5rem)/1 var(--display); }
.satellite { position: absolute; padding: .45rem .65rem; border: 1px solid var(--line); background: var(--paper); font: 700 .68rem/1 var(--mono); }
.satellite-one { top: 7%; left: 15%; }
.satellite-two { top: 25%; right: 0; }
.satellite-three { bottom: 8%; left: 14%; }
@keyframes orbit { to { transform: rotate(360deg); } }

.hero-facts {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  margin: 3rem 0 0;
  border-top: 1px solid var(--line);
}
.hero-facts div { padding: 1.5rem 1rem 0 0; border-right: 1px solid var(--line); }
.hero-facts div:last-child { border-right: 0; padding-left: 1rem; }
.hero-facts dt { font: 400 2.5rem/1 var(--display); }
.hero-facts dd { margin: .45rem 0 0; color: var(--muted); font: 600 .68rem/1.3 var(--mono); letter-spacing: .07em; text-transform: uppercase; }

.section { padding-block: clamp(5rem, 9vw, 9rem); border-bottom: 1px solid var(--line); }
.section-heading { display: flex; justify-content: space-between; align-items: end; gap: 3rem; margin-bottom: 3rem; }
.section-heading h2 { font-size: clamp(2.8rem, 5.5vw, 5.2rem); }
.section-heading > p { max-width: 34rem; margin: 0; color: var(--muted); }

.method-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; padding: 1px; margin: 0; background: var(--line); list-style: none; }
.method-grid li { min-height: 15rem; padding: 1.4rem; background: var(--paper); }
.method-grid li > span { color: var(--muted); font: 700 .7rem/1 var(--mono); }
.method-grid h3 { margin: 3.5rem 0 .6rem; font: 400 2rem/1 var(--display); }
.method-grid p { color: var(--muted); }
.method-grid code { color: var(--accent); font-size: .78rem; }
.command-deck { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1px; margin-top: 2.5rem; background: var(--line); border: 1px solid var(--line); }
.command-deck div { display: flex; justify-content: space-between; gap: 1rem; padding: 1rem; background: var(--paper-raised); }
.command-deck code { color: var(--accent); font-size: .76rem; }
.command-deck span { color: var(--muted); font-size: .75rem; }

.architecture-layout { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(18rem, .6fr); gap: 1.5rem; }
.architecture-map { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; padding: 1px; background: var(--line); }
.architecture-node {
  min-height: 9.5rem;
  padding: 1rem;
  border: 0;
  color: var(--ink);
  background: var(--paper-raised);
  text-align: left;
  cursor: pointer;
}
.architecture-node:hover, .architecture-node[aria-pressed="true"] { background: var(--paper-soft); box-shadow: inset 0 0 0 1px var(--accent); }
.architecture-node span { display: block; color: var(--accent); font: 700 .66rem/1 var(--mono); }
.architecture-node strong { display: block; margin-top: 2.7rem; font: 400 1.25rem/1.1 var(--display); }
.architecture-detail { position: sticky; top: 5.5rem; align-self: start; min-height: 24rem; padding: 1.5rem; border: 1px solid var(--line); background: var(--paper-raised); }
.architecture-detail h3 { margin: .5rem 0 1rem; font: 400 2rem/1.05 var(--display); }
.architecture-detail > p:not(.eyebrow) { color: var(--muted); }
.detail-actions { display: grid; gap: .6rem; margin: 1.25rem 0; }
.chapter-command { display: flex; align-items: center; gap: .5rem; padding: .8rem; border: 1px solid var(--line); background: var(--paper); }
.chapter-command code { min-width: 0; color: var(--accent); font-size: .68rem; overflow-wrap: anywhere; }
.copy-button { margin-left: auto; border: 0; color: var(--muted); background: transparent; font: 700 .62rem/1 var(--mono); cursor: pointer; }
.copy-button:hover { color: var(--ink); }
.source-list { display: grid; gap: .5rem; margin: 1.1rem 0 0; padding: 0; list-style: none; }
.source-list a { display: grid; grid-template-columns: 2rem 1fr; gap: .5rem; text-decoration: none; }
.source-list a:hover strong { color: var(--accent); }
.source-list span { color: var(--muted); font: 700 .62rem/1.5 var(--mono); }
.source-list strong { font-size: .78rem; }
.source-list small { grid-column: 2; color: var(--muted); font: .62rem/1.4 var(--mono); overflow-wrap: anywhere; }

.concepts-section { display: grid; grid-template-columns: 1fr 1fr; padding: 0; }
.concept { min-height: 32rem; padding: clamp(2rem, 5vw, 5rem); }
.concept h2 { font-size: clamp(2.8rem, 5vw, 5rem); }
.concept > p:last-of-type { max-width: 35rem; margin-top: 2rem; color: var(--muted); }
.concept code { color: var(--accent); font-size: .75em; }
.dark-card { background: #0b100b; color: #edf3e9; }
.light-card { background: var(--accent); color: #11170e; }
.light-card .eyebrow { color: #304d0b; }
.light-card dl { display: grid; grid-template-columns: 6rem 1fr; gap: 1rem; margin-top: 2.5rem; }
.light-card dt { font: 700 .72rem/1.5 var(--mono); text-transform: uppercase; }
.light-card dd { margin: 0; }

.loop-console { padding: clamp(1rem, 3vw, 2rem); border: 1px solid var(--line); background: #0b100b; color: #edf3e9; box-shadow: 0 2rem 7rem var(--shadow); }
.loop-toolbar { display: flex; flex-wrap: wrap; gap: .65rem; align-items: center; padding-bottom: 1.4rem; border-bottom: 1px solid rgba(212, 230, 203, .15); }
.loop-toolbar #loop-status { margin-left: auto; color: #9ca899; font: 700 .68rem/1 var(--mono); text-transform: uppercase; }
.loop-steps { display: grid; grid-template-columns: repeat(6, 1fr); gap: .6rem; padding: 2rem 0; }
.loop-step { min-height: 7.5rem; padding: .8rem; border: 1px solid rgba(212, 230, 203, .14); color: #9ca899; background: #101710; transition: .25s ease; }
.loop-step span { display: block; margin-bottom: 2rem; font: 700 .62rem/1 var(--mono); }
.loop-step strong { font: 400 1rem/1.2 var(--display); }
.loop-step.active { border-color: #c7f36b; color: #edf3e9; transform: translateY(-.2rem); }
.loop-step.complete { color: #c7f36b; }
.signal-row { display: flex; align-items: center; gap: 1rem; color: #9ca899; font: 700 .58rem/1 var(--mono); letter-spacing: .06em; }
.signal-row div { position: relative; flex: 1; height: 1px; background: rgba(212, 230, 203, .2); }
.signal-row i { position: absolute; top: -.2rem; left: 0; width: .45rem; height: .45rem; border-radius: 50%; background: #ff825f; box-shadow: 0 0 1rem #ff825f; transition: left .35s ease; }
.loop-narrative { display: grid; grid-template-columns: 3rem 1fr; gap: 1rem; margin-top: 1.5rem; padding: 1rem; background: #151d14; }
.loop-narrative span { color: #c7f36b; font: 700 .68rem/1.5 var(--mono); }
.loop-narrative p { margin: 0; }

.curriculum-heading { align-items: center; }
.search { display: flex; align-items: center; width: min(100%, 28rem); border-bottom: 1px solid var(--line); }
.search span { color: var(--accent); font-size: 1.3rem; }
.search input { width: 100%; padding: .8rem; border: 0; outline: 0; color: var(--ink); background: transparent; }
.search input::placeholder { color: var(--muted); }
.chapter-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.chapter-card { display: flex; flex-direction: column; min-height: 31rem; padding: 1.25rem; border: 1px solid var(--line); background: var(--paper-raised); }
.chapter-card:hover { border-color: color-mix(in srgb, var(--accent) 65%, var(--line)); }
.chapter-topline { display: flex; justify-content: space-between; color: var(--muted); font: 700 .62rem/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.chapter-card h3 { margin: 2.7rem 0 .8rem; font: 400 1.9rem/1.05 var(--display); }
.chapter-card > p { margin: 0; color: var(--muted); font-size: .88rem; }
.koan-list { display: grid; gap: 0; margin: 1.5rem 0; padding: 0; border-top: 1px solid var(--line); list-style: none; }
.koan-list a { display: grid; grid-template-columns: 2rem 1fr auto; align-items: center; gap: .35rem; padding: .62rem 0; border-bottom: 1px solid var(--line); text-decoration: none; }
.koan-list a:hover strong { color: var(--accent); }
.koan-list span { color: var(--muted); font: 700 .6rem/1 var(--mono); }
.koan-list strong { font-size: .72rem; }
.koan-list small { color: var(--muted); font-size: .68rem; }
.chapter-card .detail-actions { margin-top: auto; }
.chapter-card .button { width: 100%; }
.empty-state { padding: 4rem; border: 1px solid var(--line); color: var(--muted); text-align: center; }

.maintenance-section blockquote { max-width: 25ch; margin: 1rem 0 3rem; font: 400 clamp(2.4rem, 5vw, 5rem)/1.05 var(--display); letter-spacing: -.035em; }
.snapshot { display: grid; grid-template-columns: .7fr 2fr .7fr; border: 1px solid var(--line); }
.snapshot div { min-width: 0; padding: 1rem; border-right: 1px solid var(--line); }
.snapshot div:last-child { border-right: 0; }
.snapshot span { display: block; margin-bottom: .5rem; color: var(--muted); font: 700 .6rem/1 var(--mono); letter-spacing: .08em; }
.snapshot strong, .snapshot code { font-size: .74rem; overflow-wrap: anywhere; }

footer { display: flex; justify-content: space-between; gap: 1rem; padding-block: 2rem; color: var(--muted); font: 700 .64rem/1.4 var(--mono); letter-spacing: .07em; }
footer a { text-decoration: none; }
footer a:hover { color: var(--accent); }

:focus-visible { outline: 2px solid var(--signal); outline-offset: 3px; }

@media (max-width: 980px) {
  .hero { grid-template-columns: 1fr; }
  .hero-machine { width: min(85vw, 29rem); }
  .method-grid, .chapter-grid { grid-template-columns: repeat(2, 1fr); }
  .architecture-layout { grid-template-columns: 1fr; }
  .architecture-detail { position: static; }
  .loop-steps { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 680px) {
  .topbar nav { display: none; }
  .hero { gap: 2rem; }
  .hero h1 { font-size: clamp(3.2rem, 16vw, 5rem); }
  .hero-facts { grid-template-columns: 1fr; }
  .hero-facts div { border-right: 0; border-bottom: 1px solid var(--line); }
  .hero-facts div:last-child { padding-left: 0; border-bottom: 0; }
  .section-heading, .curriculum-heading { display: block; }
  .section-heading > p, .search { margin-top: 1.5rem; }
  .method-grid, .command-deck, .architecture-map, .concepts-section, .chapter-grid, .snapshot { grid-template-columns: 1fr; }
  .method-grid li { min-height: 12rem; }
  .concept { min-height: auto; }
  .loop-steps { grid-template-columns: repeat(2, 1fr); }
  .snapshot div { border-right: 0; border-bottom: 1px solid var(--line); }
  footer { 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; }
}