:root {
  --bg: #0a0610;
  --bg2: #120818;
  --panel: #1a0f1e;
  --border: #4a2040;
  --text: #f8f0f4;
  --muted: #b8a0b0;
  --heart: #f43f5e;
  --heart-glow: #fb7185;
  --gold: #fbbf24;
  --phi: #38bdf8;
  --ok: #4ade80;
  --radius: 14px;
  --font: "Segoe UI", system-ui, -apple-system, sans-serif;
  --mono: ui-monospace, "Cascadia Code", monospace;
  --page-max: min(96vw, 1100px);
  --page-pad: max(1.25rem, env(safe-area-inset-left, 1.25rem));
  --font-base: clamp(1.05rem, 0.4vw + 1rem, 1.2rem);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
  font-size: var(--font-base);
  min-height: 100dvh;
}
a { color: var(--heart-glow); text-decoration: none; }
a:hover { color: var(--gold); text-decoration: underline; }

.top {
  position: sticky; top: 0; z-index: 100;
  background: rgba(10, 6, 16, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.top .inner {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 0.75rem var(--page-pad);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.logo {
  font-weight: 700;
  letter-spacing: 0.12em;
  font-size: 0.85rem;
  color: var(--text);
}
.heart-badge { color: var(--heart); }
.top ul { display: flex; gap: 1.25rem; list-style: none; flex-wrap: wrap; }
.top a { font-size: 0.9rem; color: var(--muted); }
.top a:hover { color: var(--heart-glow); }

.hero {
  position: relative;
  min-height: 88vh;
  display: flex;
  align-items: flex-end;
  overflow: hidden;
}
.hero-bg {
  position: absolute; inset: 0;
  background: center/cover no-repeat url("../assets/images/field-research-hero.jpg");
  filter: saturate(1.15) brightness(0.5);
}
.hero-overlay {
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 0%, rgba(10,6,16,0.5) 50%, var(--bg) 100%);
}
.hero-content {
  position: relative; z-index: 2;
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 3rem var(--page-pad) max(2.5rem, env(safe-area-inset-bottom));
  width: 100%;
}
.eyebrow {
  font-size: 0.82rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--heart-glow);
  margin-bottom: 0.6rem;
}
h1 { font-size: clamp(2rem, 5vw, 3.2rem); line-height: 1.15; margin-bottom: 1rem; }
.lead { font-size: 1.15rem; color: var(--muted); max-width: 52rem; margin-bottom: 1.5rem; }
.axiom-bar { display: flex; flex-wrap: wrap; gap: 0.6rem; margin-bottom: 1.5rem; }
.axiom {
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  font-size: 0.82rem;
  color: var(--gold);
  background: rgba(251, 191, 36, 0.08);
}
.cta-row { display: flex; flex-wrap: wrap; gap: 0.75rem; }
.btn {
  display: inline-block;
  padding: 0.65rem 1.25rem;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--heart) 0%, #be123c 100%);
  color: #fff;
  font-weight: 600;
  border: none;
}
.btn:hover { color: #fff; filter: brightness(1.1); text-decoration: none; }
.btn.secondary {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--heart-glow);
}

.section-panel {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 3rem var(--page-pad);
  display: grid;
  gap: 2rem;
}
@media (min-width: 900px) {
  .section-panel { grid-template-columns: 1fr 280px; align-items: start; }
}
.section-panel.dark { background: var(--bg2); max-width: none; }
.section-panel.dark .section-inner { max-width: var(--page-max); margin: 0 auto; padding: 0 var(--page-pad); }
.section-inner.wide { max-width: 900px; }
.section-panel h2 { font-size: 1.65rem; margin-bottom: 1rem; }
.section-panel p { margin-bottom: 1rem; color: var(--muted); }
.hero-side img { width: 100%; border-radius: var(--radius); border: 1px solid var(--border); }

.spine-diagram {
  font-family: var(--mono);
  font-size: 0.78rem;
  line-height: 1.5;
  padding: 1.25rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow-x: auto;
  color: var(--heart-glow);
}

.chapter-grid-section {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 3rem var(--page-pad) 4rem;
}
.chapter-grid-section h2 { margin-bottom: 1.5rem; font-size: 1.5rem; }
.chapter-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}
.chapter-card a {
  display: block;
  padding: 1.25rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color 0.2s, transform 0.2s;
}
.chapter-card a:hover {
  border-color: var(--heart);
  transform: translateY(-2px);
  text-decoration: none;
}
.ch-num { font-size: 0.75rem; color: var(--heart-glow); letter-spacing: 0.1em; text-transform: uppercase; }
.chapter-card h3 { font-size: 1rem; margin: 0.5rem 0; color: var(--text); line-height: 1.35; }
.ch-link { font-size: 0.85rem; color: var(--gold); }

.site-foot {
  text-align: center;
  padding: 2rem var(--page-pad);
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.88rem;
}

.tag {
  display: inline-block;
  padding: 0.1rem 0.45rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  vertical-align: middle;
}
.tag.impl { background: rgba(74, 222, 128, 0.15); color: var(--ok); }
.tag.meta { background: rgba(56, 189, 248, 0.12); color: var(--phi); }
.tag.phil { background: rgba(244, 63, 94, 0.12); color: var(--heart-glow); }
.tag.vis { background: rgba(251, 191, 36, 0.12); color: var(--gold); }

.code-block {
  margin: 1.25rem 0;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  overflow: hidden;
}
.code-block pre {
  padding: 1rem 1.25rem;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.5;
  background: #08040c;
  color: #f0c4d0;
}
code {
  font-family: var(--mono);
  font-size: 0.88em;
  background: rgba(244, 63, 94, 0.1);
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
}
.table-wrap { overflow-x: auto; margin: 1.25rem 0; }
.table-wrap table { width: 100%; border-collapse: collapse; font-size: 0.95rem; }
.table-wrap th, .table-wrap td { border: 1px solid rgba(255,200,220,0.15); padding: 0.5rem 0.65rem; text-align: left; }
.table-wrap th { background: rgba(80,20,40,0.45); }
.seal { margin: 0.75rem 0; opacity: 0.85; font-size: 0.85rem; word-break: break-all; }