:root {
  --ink: #12171c;
  --ink-2: #1b2229;
  --paper: #f3efe6;
  --paper-2: #e9e2d6;
  --white: #fffdf8;
  --muted: #667078;
  --line: rgba(18, 23, 28, 0.14);
  --orange: #f06445;
  --orange-dark: #cc4629;
  --lime: #d8f05b;
  --blue: #77a9ff;
  --green: #46bc84;
  --amber: #e4a83a;
  --red: #dc5a52;
  --rail: 270px;
  --radius: 18px;
  --shadow: 0 22px 70px rgba(20, 24, 28, 0.15);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: Inter, Aptos, "Segoe UI", Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}
button, input, textarea { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { color: inherit; }
a { color: inherit; }
img { max-width: 100%; }

.skip-link {
  position: fixed;
  z-index: 1000;
  left: 12px;
  top: -60px;
  padding: 10px 14px;
  color: white;
  background: var(--ink);
  border-radius: 8px;
  transition: top .2s ease;
}
.skip-link:focus { top: 12px; }
.sr-only {
  position: absolute !important;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0);
  white-space: nowrap; border: 0;
}

.rail {
  position: fixed;
  z-index: 50;
  inset: 0 auto 0 0;
  width: var(--rail);
  padding: 30px 24px 24px;
  display: flex;
  flex-direction: column;
  color: #eef1ed;
  background: var(--ink);
  border-right: 1px solid rgba(255,255,255,.08);
}
.brand {
  display: flex;
  align-items: center;
  gap: 13px;
  color: inherit;
  text-decoration: none;
}
.brand strong { display: block; font-size: 16px; letter-spacing: -.02em; }
.brand small { display: block; margin-top: 1px; color: #99a1a4; font-size: 10px; letter-spacing: .04em; }
.brand-mark {
  width: 29px;
  height: 29px;
  display: inline-flex;
  align-items: flex-end;
  gap: 3px;
  flex: 0 0 auto;
  transform: skewY(-9deg);
}
.brand-mark i { display: block; width: 7px; border-radius: 1px; background: var(--orange); }
.brand-mark i:nth-child(1) { height: 15px; }
.brand-mark i:nth-child(2) { height: 22px; }
.brand-mark i:nth-child(3) { height: 29px; }
.brand-mark.large { width: 52px; height: 52px; gap: 5px; }
.brand-mark.large i { width: 12px; }
.brand-mark.large i:nth-child(1) { height: 27px; }
.brand-mark.large i:nth-child(2) { height: 40px; }
.brand-mark.large i:nth-child(3) { height: 52px; }

.chapter-nav { margin: auto 0; display: grid; gap: 4px; }
.chapter-nav a {
  position: relative;
  min-height: 45px;
  padding: 12px 10px 12px 43px;
  color: #899194;
  border-radius: 8px;
  text-decoration: none;
  transition: color .2s, background .2s;
}
.chapter-nav a::before {
  content: "";
  position: absolute;
  left: 0; top: 8px; bottom: 8px;
  width: 2px;
  background: transparent;
  border-radius: 2px;
}
.chapter-nav a:hover { color: #f6f6f2; background: rgba(255,255,255,.04); }
.chapter-nav a.active { color: white; background: rgba(255,255,255,.055); }
.chapter-nav a.active::before { background: var(--orange); }
.chapter-nav span { position: absolute; left: 13px; top: 13px; font: 600 10px/1.5 ui-monospace, SFMono-Regular, Consolas, monospace; }
.chapter-nav b { font-size: 12px; font-weight: 600; }
.rail-footer { display: grid; gap: 13px; }
.rail-footer p { margin: 0; color: #737d80; font-size: 9px; letter-spacing: .08em; text-transform: uppercase; }
.ask-button {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 13px;
  color: var(--ink);
  background: var(--lime);
  border: 0;
  border-radius: 9px;
  font-size: 12px;
  font-weight: 750;
  cursor: pointer;
  transition: transform .2s, background .2s;
}
.ask-button span:last-child { margin-left: auto; }
.ask-button:hover { transform: translateY(-2px); background: #e5fa77; }
.pulse-dot { width: 8px; height: 8px; display: inline-block; border-radius: 50%; background: var(--orange); box-shadow: 0 0 0 5px rgba(240,100,69,.16); }

.mobile-header { display: none; }
main, footer { margin-left: var(--rail); }
.submission-notice {
  position: relative;
  z-index: 10;
  height: 40px;
  padding: 0 5vw;
  display: flex;
  align-items: center;
  gap: 18px;
  color: #c8ceca;
  background: #222a30;
  border-bottom: 1px solid rgba(255,255,255,.08);
  font-size: 10px;
  letter-spacing: .02em;
}
.submission-notice span { color: var(--lime); font-weight: 750; letter-spacing: .08em; text-transform: uppercase; }
.submission-notice p { margin: 0; }
.submission-notice button { margin-left: auto; padding: 0; color: #e7eae6; background: none; border: 0; border-bottom: 1px solid #697177; font-size: 10px; cursor: pointer; }

.chapter { scroll-margin-top: 20px; }
.hero {
  min-height: calc(100vh - 40px);
  padding: clamp(75px, 8vw, 126px) clamp(36px, 6vw, 100px) 46px;
  display: grid;
  grid-template-columns: minmax(400px, 1.1fr) minmax(390px, .9fr);
  grid-template-rows: auto auto;
  gap: 50px 5vw;
  overflow: hidden;
  background:
    radial-gradient(circle at 74% 36%, rgba(240,100,69,.11), transparent 30%),
    linear-gradient(180deg, #f8f4ec, var(--paper));
}
.eyebrow { margin: 0 0 18px; color: var(--orange-dark); font-size: 11px; font-weight: 800; letter-spacing: .13em; text-transform: uppercase; }
h1, h2, h3, p { text-wrap: pretty; }
h1, h2 { margin: 0; font-weight: 540; letter-spacing: -.055em; line-height: .98; }
h1 { max-width: 820px; font-size: clamp(54px, 6.3vw, 98px); }
h1 em, h2 em { color: var(--orange); font-family: Georgia, "Times New Roman", serif; font-weight: 400; }
.lede { max-width: 670px; margin: 30px 0 0; color: #505960; font-size: clamp(17px, 1.4vw, 22px); line-height: 1.55; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 34px; }
.button {
  min-height: 48px;
  padding: 0 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  border: 1px solid transparent;
  border-radius: 8px;
  text-decoration: none;
  font-size: 12px;
  font-weight: 750;
  cursor: pointer;
  transition: transform .2s, box-shadow .2s, background .2s;
}
.button:hover { transform: translateY(-2px); }
.button.primary { color: white; background: var(--ink); box-shadow: 0 8px 24px rgba(18,23,28,.16); }
.button.primary:hover { background: var(--orange-dark); box-shadow: 0 11px 30px rgba(204,70,41,.2); }
.button.secondary { border-color: #c6c0b7; background: rgba(255,255,255,.45); }
.button.secondary:hover { background: white; }

.hero-visual { position: relative; min-height: 430px; align-self: center; }
.orbit { position: absolute; left: 50%; top: 50%; border: 1px solid rgba(18,23,28,.14); border-radius: 50%; transform: translate(-50%,-50%); }
.orbit::before, .orbit::after { content: ""; position: absolute; width: 7px; height: 7px; background: var(--orange); border: 4px solid var(--paper); border-radius: 50%; }
.orbit-one { width: 340px; height: 340px; animation: orbit 22s linear infinite; }
.orbit-one::before { left: 34px; top: 48px; }
.orbit-one::after { right: -4px; top: 49%; }
.orbit-two { width: 480px; height: 480px; border-style: dashed; animation: orbit 38s linear infinite reverse; }
.orbit-two::before { right: 72px; top: 20px; background: var(--blue); }
.orbit-two::after { left: 24px; bottom: 90px; background: var(--green); }
@keyframes orbit { to { transform: translate(-50%,-50%) rotate(360deg); } }
.core-mark {
  position: absolute; z-index: 2;
  left: 50%; top: 50%;
  width: 208px; height: 208px;
  padding: 35px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: white;
  text-align: center;
  background: var(--ink);
  border-radius: 50%;
  box-shadow: 0 30px 80px rgba(18,23,28,.27);
  transform: translate(-50%,-50%);
}
.core-mark .brand-mark { margin-bottom: 14px; }
.core-mark strong { font-size: 17px; line-height: 1.15; }
.core-mark small { margin-top: 8px; color: #9ca5a4; font-size: 9px; letter-spacing: .07em; text-transform: uppercase; }
.signal-card {
  position: absolute; z-index: 3;
  min-width: 125px;
  padding: 14px 16px;
  background: rgba(255,253,248,.88);
  border: 1px solid rgba(18,23,28,.14);
  border-radius: 10px;
  box-shadow: 0 13px 36px rgba(18,23,28,.1);
  backdrop-filter: blur(8px);
}
.signal-card span { display: block; font: 600 24px/1 Georgia, serif; }
.signal-card small { display: block; margin-top: 7px; color: var(--muted); font-size: 9px; letter-spacing: .06em; text-transform: uppercase; }
.signal-a { left: 1%; top: 16%; }
.signal-b { right: 0; top: 27%; }
.signal-c { left: 8%; bottom: 10%; }
.proof-ribbon { grid-column: 1 / -1; display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.proof-ribbon > div { min-height: 112px; padding: 25px 30px; display: flex; align-items: center; gap: 20px; }
.proof-ribbon > div + div { border-left: 1px solid var(--line); }
.proof-ribbon span { flex: 0 0 auto; color: var(--orange-dark); font: 400 37px/1 Georgia, serif; white-space: nowrap; }
.proof-ribbon p { margin: 0; color: var(--muted); font-size: 11px; line-height: 1.5; }
.proof-ribbon b { display: block; color: var(--ink); font-size: 12px; }
.metric-help { margin: 5px 0 0; padding: 0; display: block; color: var(--orange-dark); background: none; border: 0; border-bottom: 1px solid rgba(204,70,41,.35); font-size: 9px; font-weight: 750; cursor: pointer; }
.metric-help:hover { border-color: var(--orange-dark); }

.principle-section, .backbone-section, .prototype-section, .requirements-section { padding: clamp(88px, 10vw, 150px) clamp(36px, 7vw, 120px); }
.section-heading { max-width: 950px; }
.section-heading h2 { font-size: clamp(45px, 5.2vw, 80px); }
.section-heading > p:last-child { max-width: 690px; margin: 26px 0 0; color: var(--muted); font-size: 16px; line-height: 1.7; }
.section-heading.light { color: white; }
.section-heading.light .eyebrow { color: var(--lime); }
.section-heading.light > p:last-child { color: #aeb7b5; }
.principle-section { background: var(--white); }
.principle-grid { margin-top: 70px; display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); }
.principle { padding: 28px 7% 22px 0; }
.principle + .principle { padding-left: 8%; border-left: 1px solid var(--line); }
.principle > span { color: var(--orange-dark); font: 600 10px/1 ui-monospace, monospace; }
.principle h3 { margin: 44px 0 12px; font-size: 20px; letter-spacing: -.025em; }
.principle p { margin: 0; color: var(--muted); font-size: 13px; line-height: 1.65; }
.principle small { display: block; margin-top: 26px; color: #989f9e; font-size: 9px; letter-spacing: .04em; text-transform: uppercase; }

.lab-section { padding: clamp(88px, 10vw, 150px) clamp(30px, 6vw, 100px); background: var(--ink); }
.lab-shell { margin-top: 70px; overflow: hidden; color: #edf0ec; background: #1b2229; border: 1px solid rgba(255,255,255,.1); border-radius: var(--radius); box-shadow: 0 30px 80px rgba(0,0,0,.28); }
.lab-toolbar { min-height: 78px; padding: 16px 22px; display: flex; align-items: center; justify-content: space-between; gap: 20px; background: #202830; border-bottom: 1px solid rgba(255,255,255,.08); }
.lab-toolbar > div { display: grid; gap: 4px; }
.lab-toolbar strong { color: #9ea8a7; font-size: 11px; font-weight: 500; }
.live-indicator { display: flex; align-items: center; gap: 8px; color: #e9eeea; font-size: 10px; font-weight: 750; text-transform: uppercase; letter-spacing: .08em; }
.live-indicator i { width: 7px; height: 7px; background: var(--green); border-radius: 50%; box-shadow: 0 0 0 5px rgba(70,188,132,.12); }
.fault-button { padding: 11px 15px; color: var(--ink); background: var(--lime); border: 0; border-radius: 8px; font-size: 11px; font-weight: 800; cursor: pointer; transition: transform .2s, opacity .2s; }
.fault-button:hover { transform: translateY(-2px); }
.fault-button:disabled { opacity: .6; cursor: wait; transform: none; }
.pipeline { padding: 44px 3.5%; display: grid; grid-template-columns: minmax(135px,1fr) 38px minmax(135px,1fr) 38px minmax(135px,1fr) 38px minmax(135px,1fr); align-items: center; }
.pipeline-node { min-height: 190px; padding: 20px; background: #222b33; border: 1px solid rgba(255,255,255,.1); border-radius: 12px; transition: border .25s, background .25s, transform .25s; }
.pipeline-node.protected { border-color: rgba(216,240,91,.35); }
.node-icon { width: 36px; height: 36px; margin-bottom: 30px; display: grid; place-items: center; color: var(--ink); background: #879497; border-radius: 8px; font-size: 10px; font-weight: 900; }
.protected .node-icon { background: var(--lime); }
.pipeline-node small { display: block; color: #7f898b; font-size: 8px; font-weight: 800; letter-spacing: .09em; text-transform: uppercase; }
.pipeline-node h3 { margin: 4px 0 2px; font-size: 15px; }
.pipeline-node p { margin: 0; color: #939d9e; font-size: 10px; }
.node-status { margin-top: 17px; display: inline-flex; align-items: center; gap: 6px; color: #a8b0af; font-size: 9px; font-weight: 750; }
.node-status::before { content: ""; width: 6px; height: 6px; background: var(--green); border-radius: 50%; }
.pipeline-node.warning { border-color: var(--amber); background: rgba(228,168,58,.08); transform: translateY(-4px); }
.pipeline-node.warning .node-status { color: #f1bf61; }
.pipeline-node.warning .node-status::before { background: var(--amber); }
.pipeline-node.danger { border-color: var(--red); background: rgba(220,90,82,.09); transform: translateY(-4px); }
.pipeline-node.danger .node-status { color: #ee817a; }
.pipeline-node.danger .node-status::before { background: var(--red); }
.pipeline-node.success { border-color: var(--green); background: rgba(70,188,132,.06); }
.pipeline-link { display: flex; justify-content: center; gap: 3px; }
.pipeline-link i { width: 4px; height: 4px; background: #596367; border-radius: 50%; }
.pipeline.running .pipeline-link i { animation: signal .8s ease infinite alternate; }
.pipeline.running .pipeline-link i:nth-child(2) { animation-delay: .15s; }
.pipeline.running .pipeline-link i:nth-child(3) { animation-delay: .3s; }
@keyframes signal { to { background: var(--lime); transform: scale(1.4); } }
.recovery-panel { display: grid; grid-template-columns: .75fr 1.25fr; border-top: 1px solid rgba(255,255,255,.08); }
.recovery-summary { padding: 28px; border-right: 1px solid rgba(255,255,255,.08); }
.recovery-summary small { color: #7f898b; font-size: 8px; font-weight: 800; letter-spacing: .09em; text-transform: uppercase; }
.recovery-summary strong { display: block; margin-top: 10px; color: white; font-size: 19px; }
.recovery-summary p { margin: 8px 0 0; color: #909a9b; font-size: 11px; line-height: 1.55; }
.event-log { margin: 0; padding: 21px 27px; list-style: none; display: grid; gap: 9px; }
.event-log li { display: grid; grid-template-columns: 70px 1fr; align-items: baseline; gap: 10px; font-size: 10px; }
.event-log time { color: var(--lime); font: 600 9px/1 ui-monospace, monospace; }
.event-log span { color: #c4ccca; }
.event-log li.enter { animation: enter .3s ease both; }
@keyframes enter { from { opacity: 0; transform: translateX(8px); } }
.lab-footnote { padding: 16px 22px; display: flex; align-items: center; gap: 14px; background: #151b20; border-top: 1px solid rgba(255,255,255,.08); }
.lab-footnote p { margin: 0; color: #879193; font-size: 9px; }
.evidence-tag { padding: 5px 8px; display: inline-flex; white-space: nowrap; border-radius: 99px; font-size: 8px; font-weight: 850; letter-spacing: .06em; text-transform: uppercase; }
.evidence-tag.prototype { color: #153c29; background: #bfe9d3; }
.evidence-tag.proposed { color: #243d6f; background: #cadcff; }
.evidence-tag.needed { color: #6d4511; background: #f3d89e; }

.backbone-section { background: var(--paper); }
.scale-layout { margin-top: 72px; display: grid; grid-template-columns: 300px 1fr; gap: 60px; align-items: start; }
.scenario-controls { padding: 26px; background: var(--white); border: 1px solid var(--line); border-radius: 13px; box-shadow: 0 16px 50px rgba(18,23,28,.08); }
.scenario-controls label { margin-top: 23px; display: flex; align-items: center; justify-content: space-between; font-size: 11px; font-weight: 700; }
.scenario-controls label:first-child { margin-top: 0; }
.scenario-controls output { color: var(--orange-dark); font: 600 18px/1 Georgia, serif; }
.scenario-controls input[type=range] { width: 100%; margin: 14px 0 4px; accent-color: var(--orange); cursor: grab; }
.scenario-note { margin-top: 26px; padding-top: 20px; border-top: 1px solid var(--line); }
.scenario-note span { color: var(--orange-dark); font-size: 8px; font-weight: 850; letter-spacing: .1em; text-transform: uppercase; }
.scenario-note p { margin: 8px 0 0; color: var(--muted); font-size: 10px; line-height: 1.55; }
.architecture { display: grid; }
.arch-row { display: flex; justify-content: space-around; gap: 8px; }
.arch-row span { min-width: 53px; padding: 8px 9px; color: var(--muted); background: rgba(255,255,255,.5); border: 1px solid var(--line); border-radius: 5px; text-align: center; font: 700 8px/1 ui-monospace, monospace; text-transform: uppercase; }
.arch-arrow { width: 1px; height: 26px; margin: 0 auto; background: var(--line); position: relative; }
.arch-arrow i { position: absolute; bottom: -1px; left: -3px; width: 7px; height: 7px; border-right: 1px solid #8d9291; border-bottom: 1px solid #8d9291; transform: rotate(45deg); }
.arch-layer { min-height: 100px; padding: 18px 20px; display: grid; grid-template-columns: 1fr 1fr auto; align-items: center; gap: 18px; background: var(--white); border: 1px solid var(--line); border-radius: 11px; box-shadow: 0 7px 24px rgba(18,23,28,.05); }
.arch-layer.hot { border-left: 4px solid var(--orange); }
.arch-layer small { display: block; color: var(--orange-dark); font-size: 8px; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.arch-layer strong { display: block; margin-top: 3px; font-size: 14px; }
.arch-layer p { margin: 0; color: var(--muted); font-size: 10px; line-height: 1.5; }
.scale-badge { padding: 7px 9px; color: #38555e; background: #dceced; border-radius: 4px; font-size: 8px; white-space: nowrap; }
.consumers { margin-top: 25px; }
.design-choices { margin-top: 75px; display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--line); }
.design-choices article { padding: 25px 25px 0 0; }
.design-choices article + article { padding-left: 25px; border-left: 1px solid var(--line); }
.design-choices span { color: var(--orange-dark); font: 700 9px/1 ui-monospace, monospace; text-transform: uppercase; }
.design-choices h3 { min-height: 48px; margin: 19px 0 8px; font-size: 16px; letter-spacing: -.02em; }
.design-choices p { margin: 0; color: var(--muted); font-size: 10px; line-height: 1.6; }

.prototype-section { background: #ded9cf; }
.prototype-frame { margin-top: 65px; overflow: hidden; background: var(--ink); border: 1px solid rgba(18,23,28,.25); border-radius: 16px; box-shadow: 0 28px 80px rgba(18,23,28,.23); }
.browser-bar { height: 48px; padding: 0 15px; display: grid; grid-template-columns: 90px 1fr 120px; align-items: center; gap: 15px; color: #a5aeac; background: #171d22; border-bottom: 1px solid rgba(255,255,255,.1); font-size: 9px; }
.browser-dots { display: flex; gap: 6px; }
.browser-dots i { width: 8px; height: 8px; background: #535e62; border-radius: 50%; }
.browser-dots i:first-child { background: var(--orange); }
.browser-address { max-width: 520px; width: 100%; margin: auto; padding: 7px 12px; color: #8e9999; background: #222a30; border-radius: 5px; text-align: center; }
.browser-address span { color: var(--green); font-size: 7px; }
.browser-bar a { text-align: right; text-decoration: none; }
.prototype-stage { position: relative; height: min(690px, 69vw); min-height: 480px; background: #e9ecef; }
.prototype-stage iframe { width: 100%; height: 100%; border: 0; background: white; }
.prototype-intro { position: absolute; inset: 0; padding: 40px; display: flex; flex-direction: column; align-items: center; justify-content: center; color: white; text-align: center; background: rgba(14,19,24,.82); backdrop-filter: blur(10px); transition: opacity .35s, visibility .35s; }
.prototype-intro.hidden { opacity: 0; visibility: hidden; pointer-events: none; }
.prototype-intro h3 { max-width: 560px; margin: 18px 0 8px; font-size: clamp(28px, 4vw, 48px); font-weight: 520; letter-spacing: -.045em; }
.prototype-intro p { max-width: 570px; margin: 0; color: #b9c0bf; font-size: 13px; line-height: 1.65; }
.prototype-intro .button { margin-top: 25px; color: var(--ink); background: var(--lime); }
.try-list { margin-top: 34px; padding: 24px 26px; display: grid; grid-template-columns: 150px 1fr; gap: 30px; background: rgba(255,255,255,.32); border: 1px solid var(--line); border-radius: 12px; }
.try-list > p { margin: 4px 0 0; color: var(--orange-dark); font-size: 10px; font-weight: 800; letter-spacing: .07em; text-transform: uppercase; }
.try-list ol { margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; list-style: none; }
.try-list li { display: grid; grid-template-columns: 27px 1fr; }
.try-list li > span { grid-row: 1 / 3; color: var(--orange-dark); font: 600 10px/1.4 ui-monospace, monospace; }
.try-list b { font-size: 11px; }
.try-list small { margin-top: 3px; color: var(--muted); font-size: 9px; }

.requirements-section { background: var(--white); }
.requirements-summary { margin-top: 65px; min-height: 100px; display: grid; grid-template-columns: 150px 150px 150px 1fr; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.requirements-summary > div { padding: 20px; display: flex; flex-direction: column; justify-content: center; }
.requirements-summary > div + div { border-left: 1px solid var(--line); }
.requirements-summary strong { font: 500 28px/1 Georgia, serif; }
.requirements-summary > div > span { margin-top: 5px; color: var(--muted); font-size: 9px; text-transform: uppercase; letter-spacing: .04em; }
.requirements-summary .legend { flex-direction: row; align-items: center; justify-content: flex-end; gap: 18px; }
.requirements-summary .legend span { margin: 0; display: flex; align-items: center; gap: 6px; white-space: nowrap; }
.dot { width: 7px; height: 7px; display: inline-block; border-radius: 50%; }
.dot.prototype { background: var(--green); }
.dot.proposed { background: var(--blue); }
.dot.needed { background: var(--amber); }
.requirements-tools { margin-top: 30px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.filter-tabs { display: flex; flex-wrap: wrap; gap: 6px; }
.filter-tabs button { padding: 8px 11px; color: var(--muted); background: transparent; border: 1px solid var(--line); border-radius: 6px; font-size: 9px; font-weight: 700; cursor: pointer; }
.filter-tabs button.active { color: white; background: var(--ink); border-color: var(--ink); }
.requirement-search input { width: 220px; padding: 9px 12px; background: #faf8f3; border: 1px solid var(--line); border-radius: 6px; font-size: 10px; outline: none; }
.requirement-search input:focus { border-color: var(--orange); box-shadow: 0 0 0 3px rgba(240,100,69,.1); }
.requirements-list { margin-top: 20px; border-top: 1px solid var(--line); }
.requirement-row { min-height: 76px; padding: 14px 5px; display: grid; grid-template-columns: 68px 1fr 150px 115px; align-items: center; gap: 18px; border-bottom: 1px solid var(--line); }
.requirement-row > span:first-child { color: #9a9f9d; font: 600 9px/1 ui-monospace, monospace; }
.requirement-row h3 { margin: 0; font-size: 12px; letter-spacing: -.01em; }
.requirement-row p { margin: 4px 0 0; color: var(--muted); font-size: 9px; }
.requirement-class { color: var(--muted); font-size: 9px; }
.requirement-class b { display: block; color: var(--ink); font-size: 9px; }
.requirement-row .evidence-tag { justify-self: start; }
.empty-state { margin: 30px 0; color: var(--muted); font-size: 12px; }

.delivery-section { padding: clamp(88px, 10vw, 150px) clamp(36px, 7vw, 120px) 0; color: white; background: var(--ink); }
.delivery-path { margin-top: 70px; display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid rgba(255,255,255,.13); }
.delivery-path article { min-height: 250px; padding: 24px 22px 20px 0; }
.delivery-path article + article { padding-left: 22px; border-left: 1px solid rgba(255,255,255,.13); }
.delivery-path article > span { color: var(--lime); font: 600 9px/1 ui-monospace, monospace; }
.delivery-path small { display: block; margin-top: 38px; color: var(--orange); font-size: 8px; font-weight: 800; letter-spacing: .1em; text-transform: uppercase; }
.delivery-path h3 { margin: 7px 0 13px; font-size: 17px; letter-spacing: -.025em; }
.delivery-path p { margin: 0; color: #929d9c; font-size: 10px; line-height: 1.6; }
.decision-room { margin-top: 70px; padding: 50px; display: grid; grid-template-columns: .8fr 1.2fr; gap: 70px; background: #222a30; border: 1px solid rgba(255,255,255,.1); border-radius: var(--radius); }
.decision-room h3 { max-width: 420px; margin: 0; font-size: clamp(28px, 3vw, 43px); font-weight: 520; letter-spacing: -.04em; line-height: 1.05; }
.decision-room ul { margin: 0; padding: 0; list-style: none; }
.decision-room li { min-height: 57px; padding: 13px 0; display: grid; grid-template-columns: 35px 1fr; align-items: center; color: #c8cfcd; border-bottom: 1px solid rgba(255,255,255,.09); font-size: 11px; }
.decision-room li span { color: var(--lime); font: 600 9px/1 ui-monospace, monospace; }
.closing { margin: 110px calc(clamp(36px, 7vw, 120px) * -1) 0; padding: 95px clamp(36px, 7vw, 120px); color: var(--ink); background: var(--orange); }
.closing .brand-mark i { background: var(--ink); }
.closing .eyebrow { margin-top: 25px; color: #652514; }
.closing h2 { max-width: 960px; font-size: clamp(43px, 5.5vw, 83px); }
.light-button.button.primary { color: var(--ink); background: var(--lime); box-shadow: none; }
.light-button.button.primary:hover { background: white; }
.dark-outline { border-color: rgba(18,23,28,.5); }
.dark-outline:hover { background: rgba(255,255,255,.2); }

footer { min-height: 65px; padding: 0 5vw; display: flex; align-items: center; gap: 28px; color: #8f9999; background: #0b0f12; font-size: 9px; }
footer p:first-child { color: #e2e6e2; font-weight: 750; }
footer button { margin-left: auto; padding: 0; color: #bec5c3; background: none; border: 0; border-bottom: 1px solid #4b5557; font-size: 9px; cursor: pointer; }

.guide-backdrop { position: fixed; z-index: 90; inset: 0; visibility: hidden; opacity: 0; background: rgba(10,14,17,.48); backdrop-filter: blur(3px); transition: opacity .3s, visibility .3s; }
.guide {
  position: fixed; z-index: 100;
  inset: 0 0 0 auto;
  width: min(470px, 100vw);
  display: grid;
  grid-template-rows: auto auto 1fr auto auto auto;
  color: var(--ink);
  background: #fbf8f1;
  box-shadow: -20px 0 60px rgba(0,0,0,.22);
  transform: translateX(102%);
  transition: transform .35s cubic-bezier(.22,.9,.3,1);
}
body.guide-open { overflow: hidden; }
body.guide-open .guide { transform: translateX(0); }
body.guide-open .guide-backdrop { visibility: visible; opacity: 1; }
.guide > header { min-height: 75px; padding: 16px 18px; display: flex; align-items: center; justify-content: space-between; color: white; background: var(--ink); }
.guide > header > div { display: flex; align-items: center; gap: 14px; }
.guide > header p { margin: 0; }
.guide > header b { display: block; font-size: 14px; }
.guide > header small { display: block; margin-top: 2px; color: #9da7a5; font-size: 9px; }
.icon-button { width: 34px; height: 34px; display: grid; place-items: center; color: white; background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.15); border-radius: 7px; font-size: 18px; cursor: pointer; }
.guide-context { padding: 12px 18px; display: flex; align-items: center; justify-content: space-between; background: #e8e3d9; border-bottom: 1px solid var(--line); font-size: 9px; }
.guide-context span { color: var(--muted); text-transform: uppercase; letter-spacing: .06em; }
.guide-context b { font-weight: 700; }
.guide-messages { min-height: 0; padding: 20px 18px; overflow-y: auto; display: flex; flex-direction: column; gap: 15px; }
.message { display: flex; gap: 10px; max-width: 92%; animation: enter .3s ease both; }
.message.user { margin-left: auto; flex-direction: row-reverse; }
.avatar { width: 27px; height: 27px; flex: 0 0 27px; display: grid; place-items: center; color: white; background: var(--orange); border-radius: 7px; font-size: 10px; font-weight: 900; }
.user .avatar { color: var(--ink); background: var(--paper-2); }
.message > div:last-child { padding: 11px 13px; background: white; border: 1px solid var(--line); border-radius: 5px 12px 12px 12px; box-shadow: 0 5px 17px rgba(18,23,28,.04); }
.message.user > div:last-child { background: var(--ink); border-color: var(--ink); border-radius: 12px 5px 12px 12px; }
.message p { margin: 0; font-size: 11px; line-height: 1.6; white-space: pre-line; }
.message.user p { color: white; }
.message small { display: block; margin-top: 9px; color: #8a9292; font-size: 8px; line-height: 1.5; }
.message a { margin-top: 10px; display: inline-block; color: var(--orange-dark); font-size: 9px; font-weight: 750; }
.suggestions { padding: 0 18px 13px; display: flex; gap: 6px; overflow-x: auto; }
.suggestions button { padding: 7px 9px; flex: 0 0 auto; color: #3f484c; background: transparent; border: 1px solid #c7c3bb; border-radius: 99px; font-size: 8px; cursor: pointer; }
.suggestions button:hover { color: var(--orange-dark); border-color: var(--orange); }
.guide-form { padding: 12px 15px; display: grid; grid-template-columns: 1fr 40px; gap: 8px; border-top: 1px solid var(--line); }
.guide-form textarea { padding: 10px 11px; resize: none; background: white; border: 1px solid #c7c3bb; border-radius: 8px; font-size: 10px; outline: none; }
.guide-form textarea:focus { border-color: var(--orange); box-shadow: 0 0 0 3px rgba(240,100,69,.1); }
.guide-form button { color: white; background: var(--ink); border: 0; border-radius: 8px; font-size: 19px; cursor: pointer; }
.guide-disclaimer { margin: 0; padding: 0 18px 13px; color: #8a9292; font-size: 8px; line-height: 1.5; }
.noscript { position: fixed; z-index: 200; inset: auto 20px 20px calc(var(--rail) + 20px); padding: 14px; background: white; border: 1px solid var(--red); border-radius: 8px; }

.reveal { opacity: 0; transform: translateY(22px); transition: opacity .7s ease, transform .7s cubic-bezier(.2,.8,.2,1); }
.reveal.visible { opacity: 1; transform: none; }

@media (max-width: 1100px) {
  :root { --rail: 220px; }
  .rail { padding-inline: 18px; }
  .hero { grid-template-columns: 1fr; }
  .hero-visual { max-width: 620px; width: 100%; margin: 0 auto; }
  .pipeline { grid-template-columns: repeat(4, 1fr); gap: 10px; }
  .pipeline-link { display: none; }
  .scale-layout { grid-template-columns: 250px 1fr; gap: 30px; }
  .arch-layer { grid-template-columns: 1fr auto; }
  .arch-layer p { display: none; }
  .design-choices, .delivery-path { grid-template-columns: repeat(2, 1fr); }
  .design-choices article:nth-child(3), .delivery-path article:nth-child(3) { border-left: 0; }
  .decision-room { gap: 40px; }
}

@media (max-width: 780px) {
  :root { --rail: 0px; }
  .rail { display: none; }
  .mobile-header { position: sticky; z-index: 60; top: 0; height: 63px; padding: 0 17px; display: flex; align-items: center; justify-content: space-between; color: white; background: rgba(18,23,28,.97); border-bottom: 1px solid rgba(255,255,255,.1); backdrop-filter: blur(10px); }
  .mobile-header .brand strong { font-size: 13px; }
  .mobile-header .brand small { font-size: 8px; }
  main, footer { margin-left: 0; }
  .submission-notice { height: auto; min-height: 42px; padding: 8px 17px; }
  .submission-notice p { display: none; }
  .hero { min-height: auto; padding: 74px 20px 35px; gap: 38px; }
  h1 { font-size: clamp(49px, 14vw, 72px); }
  .lede { font-size: 16px; }
  .hero-actions { flex-direction: column; align-items: stretch; }
  .button { width: 100%; }
  .hero-visual { min-height: 350px; transform: scale(.86); }
  .orbit-one { width: 290px; height: 290px; }
  .orbit-two { width: 390px; height: 390px; }
  .core-mark { width: 178px; height: 178px; }
  .signal-a { left: -9%; }
  .signal-b { right: -9%; }
  .signal-c { left: -3%; }
  .proof-ribbon { grid-template-columns: 1fr; }
  .proof-ribbon > div { min-height: 88px; padding: 19px 12px; }
  .proof-ribbon > div + div { border-left: 0; border-top: 1px solid var(--line); }
  .principle-section, .backbone-section, .prototype-section, .requirements-section, .lab-section, .delivery-section { padding: 80px 20px; }
  .section-heading h2 { font-size: clamp(42px, 12vw, 61px); }
  .principle-grid, .design-choices, .delivery-path { grid-template-columns: 1fr; }
  .principle + .principle, .design-choices article + article, .delivery-path article + article { padding-left: 0; border-left: 0; border-top: 1px solid var(--line); }
  .principle h3 { margin-top: 25px; }
  .lab-shell { margin-inline: -8px; }
  .lab-toolbar { align-items: stretch; flex-direction: column; }
  .pipeline { padding: 25px 17px; grid-template-columns: 1fr; }
  .pipeline-node { min-height: auto; }
  .node-icon { margin-bottom: 13px; }
  .recovery-panel { grid-template-columns: 1fr; }
  .recovery-summary { border-right: 0; border-bottom: 1px solid rgba(255,255,255,.08); }
  .lab-footnote { align-items: flex-start; flex-direction: column; }
  .scale-layout { grid-template-columns: 1fr; }
  .architecture { font-size: 90%; }
  .arch-row { flex-wrap: wrap; }
  .arch-layer { grid-template-columns: 1fr; }
  .scale-badge { justify-self: start; }
  .design-choices article:nth-child(3), .delivery-path article:nth-child(3) { border-top: 1px solid var(--line); }
  .prototype-frame { margin-inline: -8px; }
  .browser-bar { grid-template-columns: 50px 1fr; }
  .browser-bar > a { display: none; }
  .prototype-stage { min-height: 540px; height: 80vh; }
  .prototype-intro { padding: 25px; }
  .try-list { grid-template-columns: 1fr; }
  .try-list ol { grid-template-columns: 1fr; }
  .requirements-summary { grid-template-columns: repeat(3, 1fr); }
  .requirements-summary .legend { grid-column: 1 / -1; justify-content: flex-start; border-top: 1px solid var(--line); border-left: 0; }
  .requirements-tools { align-items: stretch; flex-direction: column; }
  .requirement-search input { width: 100%; }
  .requirement-row { grid-template-columns: 48px 1fr; gap: 9px; }
  .requirement-class, .requirement-row .evidence-tag { grid-column: 2; }
  .decision-room { padding: 30px 22px; grid-template-columns: 1fr; gap: 30px; }
  .closing { margin: 75px -20px -80px; padding: 75px 20px; }
  footer { padding: 24px 20px; align-items: flex-start; flex-direction: column; gap: 8px; }
  footer p { margin: 0; }
  footer button { margin: 8px 0 0; }
  .noscript { left: 20px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
  .reveal { opacity: 1; transform: none; }
}

@media print {
  @page { margin: 12mm; }
  body { color: #111; background: white; font-size: 10pt; }
  .rail, .mobile-header, .submission-notice, .guide, .guide-backdrop, .hero-visual, .hero-actions, .lab-shell, .scenario-controls, .prototype-frame, .requirements-tools, footer { display: none !important; }
  main { margin: 0; }
  .hero, .principle-section, .backbone-section, .prototype-section, .requirements-section, .lab-section, .delivery-section { min-height: 0; padding: 14mm 0; color: #111; background: white; }
  .hero { display: block; }
  .reveal { opacity: 1; transform: none; }
  h1 { font-size: 45pt; }
  .section-heading h2, .closing h2 { font-size: 30pt; }
  .section-heading.light { color: #111; }
  .section-heading.light > p:last-child, .delivery-path p { color: #555; }
  .proof-ribbon, .principle-grid, .design-choices, .delivery-path { break-inside: avoid; }
  .closing { margin: 15mm 0 0; padding: 15mm 0 0; color: #111; background: white; border-top: 2px solid #111; }
}