:root {
  --paper: #f5f0e7;
  --paper-light: #fbf8f2;
  --ink: #2d2a26;
  --muted: #70685e;
  --line: #d1c6b5;
  --accent: #8c4e2f;
  --accent-deep: #67341f;
  --accent-soft: #ead6c9;
  --blue: #315d6e;
  --blue-soft: #dce8ea;
  --green: #315c46;
  --green-soft: #dde8df;
  --gold: #805f16;
  --gold-soft: #eee4c8;
  --panel: rgba(255, 253, 248, .90);
  --shadow: 0 14px 36px rgba(51, 39, 28, .10);
  --radius: 18px;
  --content: 1160px;
  font-family: Georgia, "Times New Roman", serif;
  color: var(--ink);
  background: var(--paper);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 10% 0%, rgba(140,78,47,.09), transparent 28rem),
    radial-gradient(circle at 95% 20%, rgba(49,93,110,.06), transparent 32rem),
    linear-gradient(180deg, var(--paper-light), var(--paper));
}
a { color: var(--accent-deep); text-decoration-thickness: .08em; text-underline-offset: .18em; }
a:hover { color: var(--accent); }
button, input, select, textarea { font: inherit; }
.skip-link {
  position: fixed; left: 12px; top: -60px; z-index: 100;
  padding: 10px 14px; background: var(--ink); color: white;
  border-radius: 8px; transition: top .2s;
}
.skip-link:focus { top: 12px; }
.site-header {
  position: sticky; top: 0; z-index: 50;
  border-bottom: 1px solid rgba(209,198,181,.82);
  background: rgba(251,248,242,.94);
  backdrop-filter: blur(12px);
}
.header-inner {
  max-width: var(--content); margin: 0 auto; padding: 12px 20px;
  display: flex; align-items: center; justify-content: space-between; gap: 18px;
}
.brand {
  display: inline-flex; align-items: center; gap: 10px;
  color: var(--ink); text-decoration: none;
}
.brand-mark {
  display: grid; place-items: center; width: 38px; height: 38px;
  border: 2px solid var(--accent); border-radius: 50%;
  color: var(--accent); font-size: 1.5rem;
}
.brand strong { display: block; font-size: 1rem; }
.brand small {
  display: block; margin-top: 2px; color: var(--muted);
  font-family: system-ui, sans-serif; font-size: .67rem;
}
.site-nav { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 3px; }
.site-nav a {
  padding: 8px 9px; border-radius: 8px; color: var(--muted);
  text-decoration: none; font-family: system-ui, sans-serif;
  font-size: .76rem; font-weight: 680;
}
.site-nav a:hover, .site-nav a.active { color: var(--accent-deep); background: var(--accent-soft); }
.nav-toggle {
  display: none; border: 1px solid var(--line); border-radius: 8px;
  padding: 7px 10px; background: white; color: var(--ink);
  font-family: system-ui, sans-serif; font-size: .8rem; font-weight: 700;
}
.hero, .page-hero {
  max-width: var(--content); margin: 0 auto; padding: clamp(56px, 9vw, 105px) 20px 42px;
}
.hero { display: grid; grid-template-columns: minmax(0, 1.3fr) minmax(260px, .7fr); gap: 42px; align-items: center; }
.eyebrow {
  margin: 0 0 10px; color: var(--accent); font-family: system-ui, sans-serif;
  font-size: .74rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase;
}
h1, h2, h3 { text-wrap: balance; }
h1 {
  margin: 0; max-width: 900px; font-weight: 560;
  font-size: clamp(2.5rem, 6vw, 5.6rem); line-height: .98; letter-spacing: -.035em;
}
.page-hero h1 { font-size: clamp(2.3rem, 5vw, 4.4rem); }
.lede {
  max-width: 780px; margin: 22px 0 0; color: var(--muted);
  font-size: clamp(1.08rem, 2vw, 1.35rem); line-height: 1.6;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 27px; }
.button {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 42px; padding: 10px 15px; border: 1px solid var(--line);
  border-radius: 999px; color: var(--ink); background: rgba(255,255,255,.76);
  text-decoration: none; font-family: system-ui, sans-serif;
  font-size: .82rem; font-weight: 750;
}
.button:hover { border-color: var(--accent); background: white; }
.button.primary { border-color: var(--accent); color: white; background: var(--accent); }
.button.primary:hover { color: white; background: var(--accent-deep); }
.hero-diagram, .diagram-card {
  padding: 22px; border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--panel); box-shadow: var(--shadow);
}
.loop {
  display: grid; gap: 10px;
}
.loop-step {
  position: relative; padding: 13px 15px; border: 1px solid var(--line);
  border-radius: 12px; background: white;
}
.loop-step:not(:last-child)::after {
  content: "↓"; position: absolute; left: 50%; bottom: -17px; z-index: 2;
  color: var(--accent); font-family: system-ui, sans-serif; font-weight: 900;
}
.loop-step strong { display: block; }
.loop-step span { display: block; margin-top: 3px; color: var(--muted); font-family: system-ui, sans-serif; font-size: .77rem; }
.section { max-width: var(--content); margin: 0 auto; padding: 46px 20px; }
.section.narrow { max-width: 880px; }
.section-header { max-width: 780px; margin-bottom: 24px; }
.section-header h2 { margin: 0; font-size: clamp(1.75rem, 3.5vw, 3rem); line-height: 1.08; font-weight: 560; }
.section-header p { color: var(--muted); font-size: 1.05rem; line-height: 1.6; }
.grid { display: grid; gap: 16px; }
.grid.two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid.four { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.card {
  padding: 22px; border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--panel); box-shadow: 0 8px 24px rgba(51,39,28,.06);
}
.card h2, .card h3 { margin: 0 0 9px; font-weight: 580; line-height: 1.15; }
.card h3 { font-size: 1.25rem; }
.card p { margin: 0; color: var(--muted); line-height: 1.55; }
.card p + p { margin-top: 10px; }
.card .tag { margin-bottom: 12px; }
.card-link { display: inline-block; margin-top: 15px; font-family: system-ui, sans-serif; font-size: .78rem; font-weight: 750; }
.tag {
  display: inline-flex; padding: 5px 8px; border-radius: 999px;
  background: var(--accent-soft); color: var(--accent-deep);
  font-family: system-ui, sans-serif; font-size: .67rem; font-weight: 800;
  letter-spacing: .06em; text-transform: uppercase;
}
.tag.research { color: var(--blue); background: var(--blue-soft); }
.tag.hypothesis { color: var(--gold); background: var(--gold-soft); }
.tag.observation { color: var(--green); background: var(--green-soft); }
.statement {
  padding: clamp(25px, 5vw, 48px); border-left: 5px solid var(--accent);
  background: rgba(234,214,201,.33); font-size: clamp(1.35rem, 3vw, 2.35rem);
  line-height: 1.35;
}
.statement cite { display: block; margin-top: 16px; color: var(--muted); font-family: system-ui, sans-serif; font-size: .72rem; font-style: normal; }
.flow {
  display: flex; flex-wrap: wrap; align-items: stretch; gap: 8px;
  margin: 22px 0;
}
.flow-item {
  flex: 1 1 130px; min-width: 120px; padding: 15px 12px;
  border: 1px solid var(--line); border-radius: 12px; background: white; text-align: center;
}
.flow-item strong { display: block; }
.flow-item span { display: block; margin-top: 4px; color: var(--muted); font-family: system-ui, sans-serif; font-size: .7rem; }
.flow-arrow { align-self: center; color: var(--accent); font-family: system-ui, sans-serif; font-size: 1.1rem; font-weight: 900; }
.callout {
  margin: 22px 0; padding: 18px 20px; border: 1px solid var(--line);
  border-radius: 14px; background: rgba(255,255,255,.55);
}
.callout strong { display: block; margin-bottom: 6px; }
.callout p { margin: 0; color: var(--muted); line-height: 1.55; }
.list-clean { margin: 0; padding: 0; list-style: none; }
.list-clean li { padding: 9px 0 9px 24px; border-bottom: 1px solid rgba(209,198,181,.65); position: relative; line-height: 1.45; }
.list-clean li::before { content: "→"; position: absolute; left: 0; color: var(--accent); font-family: system-ui, sans-serif; }
.list-clean li:last-child { border-bottom: 0; }
.meta-list { display: grid; gap: 8px; margin: 14px 0 0; padding: 0; list-style: none; }
.meta-list li {
  display: flex; gap: 10px; align-items: baseline; color: var(--muted);
  font-family: system-ui, sans-serif; font-size: .8rem;
}
.meta-list strong { min-width: 95px; color: var(--ink); }
.compare {
  overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); background: white;
}
table { width: 100%; border-collapse: collapse; }
th, td { padding: 13px 14px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { color: var(--accent-deep); background: var(--accent-soft); font-family: system-ui, sans-serif; font-size: .76rem; }
td { line-height: 1.45; }
tr:last-child td { border-bottom: 0; }
.prototype-frame {
  width: 100%; min-height: 860px; border: 1px solid var(--line);
  border-radius: var(--radius); background: white; box-shadow: var(--shadow);
}
.source-list { display: grid; gap: 10px; }
.source-item {
  display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 16px;
  align-items: center; padding: 15px 17px; border: 1px solid var(--line);
  border-radius: 12px; background: white;
}
.source-item strong { display: block; }
.source-item span { display: block; margin-top: 4px; color: var(--muted); font-family: system-ui, sans-serif; font-size: .77rem; }
.status-strip {
  display: flex; flex-wrap: wrap; gap: 8px; margin-top: 18px;
}
.status-chip {
  padding: 7px 10px; border-radius: 999px; font-family: system-ui, sans-serif;
  font-size: .73rem; font-weight: 750; background: white; border: 1px solid var(--line);
}
.site-footer {
  max-width: var(--content); margin: 46px auto 0; padding: 28px 20px 38px;
  border-top: 1px solid var(--line); display: flex; justify-content: space-between; gap: 25px;
  color: var(--muted); font-family: system-ui, sans-serif; font-size: .76rem; line-height: 1.45;
}
.site-footer p { max-width: 620px; margin: 5px 0 0; }
.footer-links { display: flex; flex-wrap: wrap; gap: 12px; align-items: flex-start; }
@media (max-width: 900px) {
  .nav-toggle { display: inline-block; }
  .site-nav {
    display: none; position: absolute; top: 64px; left: 12px; right: 12px;
    padding: 10px; border: 1px solid var(--line); border-radius: 12px;
    background: var(--paper-light); box-shadow: var(--shadow);
  }
  .site-nav.open { display: grid; grid-template-columns: repeat(2, 1fr); }
  .site-nav a { padding: 11px; }
  .hero { grid-template-columns: 1fr; }
  .grid.three, .grid.four { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 650px) {
  .grid.two, .grid.three, .grid.four { grid-template-columns: 1fr; }
  .flow { display: grid; grid-template-columns: 1fr; }
  .flow-arrow { transform: rotate(90deg); text-align: center; }
  .source-item { grid-template-columns: 1fr; }
  .site-footer { display: block; }
  .footer-links { margin-top: 16px; }
  .prototype-frame { min-height: 1000px; }
}
@media print {
  .site-header, .site-footer, .hero-actions, .nav-toggle { display: none !important; }
  body { background: white; }
  .hero, .page-hero, .section { max-width: none; padding-left: 0; padding-right: 0; }
  .card, .diagram-card, .hero-diagram { box-shadow: none; break-inside: avoid; }
}