:root {
  color-scheme: light;
  --ink: #111820;
  --muted: #52606c;
  --paper: #f4f1e9;
  --paper-bright: #fffdf8;
  --navy: #17324d;
  --blue: #2f5973;
  --green: #667454;
  --oxblood: #6c3947;
  --line: #d8d2c5;
  --shadow: 0 22px 60px rgba(17, 24, 32, 0.12);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
}
a { color: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button:focus-visible, a:focus-visible { outline: 3px solid #dd9f44; outline-offset: 3px; }
.skip-link { position: absolute; left: 1rem; top: -5rem; z-index: 20; background: var(--paper-bright); padding: .75rem 1rem; border: 2px solid var(--ink); }
.skip-link:focus { top: 1rem; }

.site-header {
  min-height: 74px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  padding: 1rem clamp(1.25rem, 4vw, 4rem);
  border-bottom: 1px solid rgba(255,255,255,.13);
  background: var(--ink);
  color: white;
}
.brand { display: inline-flex; align-items: center; gap: .8rem; text-decoration: none; font-weight: 750; letter-spacing: -.015em; }
.brand-mark { display: grid; place-items: center; width: 38px; height: 38px; border: 1px solid rgba(255,255,255,.45); color: #f0c27b; font-size: .8rem; letter-spacing: .08em; }
.brand-muted { color: #b5c1ca; font-weight: 550; }
nav { display: flex; align-items: center; gap: 1.25rem; font-size: .9rem; }
nav a { color: #d8e0e6; text-decoration: none; }
nav a:hover { color: white; }
.nav-cta { padding: .55rem .8rem; border: 1px solid rgba(255,255,255,.35); }

main { overflow: hidden; }
.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(320px, .7fr);
  gap: clamp(2rem, 6vw, 7rem);
  align-items: center;
  padding: clamp(4.5rem, 10vw, 8.5rem) clamp(1.25rem, 7vw, 7rem);
  background:
    radial-gradient(circle at 83% 24%, rgba(47, 89, 115, .42), transparent 26%),
    linear-gradient(135deg, #0f1820 0%, #172b3c 54%, #1f3f4a 100%);
  color: white;
}
.hero-copy { max-width: 850px; }
.kicker { margin: 0 0 .75rem; text-transform: uppercase; letter-spacing: .14em; font-weight: 800; font-size: .72rem; color: #b87d45; }
.hero .kicker, .walkthrough .kicker { color: #efbf75; }
h1, h2, h3 { margin-top: 0; line-height: 1.08; letter-spacing: -.04em; }
h1 { margin-bottom: 1.5rem; max-width: 900px; font-size: clamp(2.85rem, 6vw, 6.5rem); font-weight: 760; }
h2 { font-size: clamp(2rem, 4vw, 3.75rem); }
h3 { font-size: clamp(1.45rem, 2.5vw, 2.2rem); }
.hero-lede { max-width: 740px; color: #d0d9df; font-size: clamp(1.05rem, 1.5vw, 1.28rem); }
.hero-actions { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: 2.2rem; }
.button { display: inline-flex; justify-content: center; align-items: center; min-height: 46px; padding: .7rem 1rem; border: 1px solid transparent; border-radius: 0; font: inherit; font-weight: 750; text-decoration: none; cursor: pointer; transition: transform .18s ease, background .18s ease; }
.button:hover { transform: translateY(-2px); }
.button.primary { background: #f0c27b; color: #111820; }
.button.secondary { background: transparent; color: inherit; border-color: currentColor; }

.scenario-card { padding: clamp(1.4rem, 3vw, 2.25rem); border: 1px solid rgba(255,255,255,.2); background: rgba(9, 16, 22, .56); box-shadow: var(--shadow); backdrop-filter: blur(12px); }
.scenario-heading { display: flex; align-items: center; gap: .65rem; padding-bottom: 1rem; border-bottom: 1px solid rgba(255,255,255,.15); font-weight: 750; }
.status-dot { width: 9px; height: 9px; border-radius: 50%; background: #efbf75; box-shadow: 0 0 0 5px rgba(239,191,117,.14); }
.fictional-label { margin-left: auto; padding: .18rem .4rem; background: rgba(255,255,255,.09); color: #d4dde3; font-size: .7rem; text-transform: uppercase; letter-spacing: .08em; }
.scenario-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; margin: 1.4rem 0; }
.scenario-grid div { padding: .8rem; background: rgba(255,255,255,.06); }
.scenario-grid dt { color: #aebbc4; font-size: .75rem; }
.scenario-grid dd { margin: .1rem 0 0; font-size: 1.2rem; font-weight: 800; }
.scenario-card > p { margin: 0; color: #b9c5cc; font-size: .85rem; }

.principles { display: grid; grid-template-columns: repeat(3, 1fr); background: var(--paper-bright); border-bottom: 1px solid var(--line); }
.principles article { min-height: 210px; padding: 2.3rem clamp(1.3rem, 3vw, 3.2rem); border-right: 1px solid var(--line); }
.principles article:last-child { border-right: 0; }
.principles span { color: var(--oxblood); font-weight: 850; }
.principles h2 { margin: .75rem 0; font-size: 1.25rem; letter-spacing: -.02em; }
.principles p { margin: 0; color: var(--muted); }

.walkthrough { padding: clamp(4.5rem, 9vw, 8rem) clamp(1.25rem, 7vw, 7rem); background: var(--ink); color: white; }
.section-heading { display: flex; justify-content: space-between; gap: 2rem; align-items: end; margin-bottom: 2.5rem; }
.section-heading h2 { margin-bottom: 0; }
.section-heading > p { max-width: 460px; color: #aebbc4; }
.stage-progress { height: 3px; background: rgba(255,255,255,.12); }
.stage-progress span { display: block; width: 20%; height: 100%; background: #f0c27b; transition: width .25s ease; }
.stage-tabs { display: grid; grid-template-columns: repeat(5, 1fr); border-bottom: 1px solid rgba(255,255,255,.15); }
.stage-tabs button { padding: 1.1rem .7rem; border: 0; border-right: 1px solid rgba(255,255,255,.1); background: transparent; color: #91a0aa; font: inherit; font-weight: 730; cursor: pointer; }
.stage-tabs button[aria-selected="true"] { background: rgba(255,255,255,.08); color: #f0c27b; }
.stage-panel { display: grid; grid-template-columns: minmax(0, 1fr) minmax(340px, .85fr); gap: clamp(2rem, 5vw, 6rem); min-height: 630px; padding: clamp(2rem, 5vw, 5rem); background: #16232d; }
.stage-content { align-self: center; }
.stage-summary { max-width: 720px; color: #c1ccd3; font-size: 1.08rem; }
.evidence-list { display: grid; gap: .7rem; margin: 2rem 0; }
.evidence-item { display: grid; grid-template-columns: 110px 1fr; gap: 1rem; padding: .8rem 0; border-bottom: 1px solid rgba(255,255,255,.12); }
.evidence-status { color: #f0c27b; font-size: .72rem; font-weight: 800; text-transform: uppercase; letter-spacing: .08em; }
.evidence-item p { margin: 0; color: #e0e6e9; }
.stage-output { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; margin: 2rem 0; }
.stage-output > div { padding: 1rem; border: 1px solid rgba(255,255,255,.15); }
.label { color: #91a0aa; font-size: .7rem; text-transform: uppercase; letter-spacing: .09em; font-weight: 800; }
.stage-output p { margin: .45rem 0 0; }
.text-link { color: #f0c27b; font-weight: 780; text-decoration-thickness: 1px; text-underline-offset: 4px; }
.stage-visual { align-self: center; margin: 0; padding: 1rem; background: #f8f5ed; color: var(--ink); box-shadow: var(--shadow); transform: rotate(1deg); }
.stage-visual img { display: block; width: 100%; aspect-ratio: 4 / 3; object-fit: cover; object-position: top left; border: 1px solid #ddd6c8; }
.stage-visual figcaption { padding: .8rem .2rem 0; color: #59636c; font-size: .78rem; }
.stage-controls { display: grid; grid-template-columns: 1fr auto 1fr; gap: 1rem; align-items: center; margin-top: 1rem; }
.stage-controls button:first-child { justify-self: start; }
.stage-controls button:last-child { justify-self: end; }
.stage-controls p { color: #91a0aa; }

.decision { display: grid; grid-template-columns: 1.25fr .75fr; gap: clamp(2rem, 6vw, 7rem); padding: clamp(4rem, 8vw, 7rem) clamp(1.25rem, 7vw, 7rem); background: #d8c9b4; }
.decision .kicker { color: var(--oxblood); }
.decision h2 { max-width: 800px; }
.decision > div > p:not(.kicker) { max-width: 780px; color: #3e4952; font-size: 1.08rem; }
.decision-actions { display: flex; flex-direction: column; justify-content: center; gap: .75rem; }
.decision-actions .button { width: 100%; }
#copy-status { min-height: 1.5rem; margin: 0; color: #46535d; font-size: .85rem; }

.proof { padding: clamp(4rem, 8vw, 7rem) clamp(1.25rem, 7vw, 7rem); background: var(--paper-bright); }
.proof .kicker { color: var(--oxblood); }
.proof-grid { display: grid; grid-template-columns: repeat(4, 1fr); border: 1px solid var(--line); }
.proof-grid article { min-height: 230px; padding: 1.7rem; border-right: 1px solid var(--line); }
.proof-grid article:last-child { border-right: 0; }
.proof-grid h3 { font-size: 1.25rem; letter-spacing: -.025em; }
.proof-grid p { color: var(--muted); }

footer { padding: 2.5rem clamp(1.25rem, 7vw, 7rem); background: #0e151b; color: #aebbc4; font-size: .85rem; }
footer p { max-width: 900px; }
footer a { color: white; }
.noscript { margin: 0; padding: 1rem; background: #fff0cb; color: #111820; text-align: center; }

@media (max-width: 980px) {
  .hero, .stage-panel, .decision { grid-template-columns: 1fr; }
  .hero { padding-top: 5rem; }
  .scenario-card { max-width: 680px; }
  .principles { grid-template-columns: 1fr; }
  .principles article { min-height: auto; border-right: 0; border-bottom: 1px solid var(--line); }
  .stage-tabs { grid-template-columns: 1fr; }
  .stage-tabs button { text-align: left; border-right: 0; border-bottom: 1px solid rgba(255,255,255,.08); }
  .stage-panel { min-height: 0; }
  .stage-visual { transform: none; }
  .proof-grid { grid-template-columns: repeat(2, 1fr); }
  .proof-grid article:nth-child(2) { border-right: 0; }
  .proof-grid article:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
}

@media (max-width: 680px) {
  .site-header { align-items: flex-start; }
  .brand-muted, nav a:not(.nav-cta) { display: none; }
  h1 { font-size: clamp(2.55rem, 13vw, 4rem); }
  .scenario-grid, .stage-output, .proof-grid { grid-template-columns: 1fr; }
  .section-heading { display: block; }
  .section-heading > p { margin-top: 1rem; }
  .evidence-item { grid-template-columns: 1fr; gap: .25rem; }
  .stage-panel { padding: 1.4rem; }
  .stage-controls { grid-template-columns: 1fr 1fr; }
  .stage-controls p { grid-column: 1 / -1; grid-row: 1; text-align: center; margin: 0; }
  .stage-controls button { width: 100%; }
  .proof-grid article { border-right: 0; border-bottom: 1px solid var(--line); }
}

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