/* ===================================================================
   Can You Beat the Machine? — Design System
   Amber (human) / Cyan (AI) duality on dark backgrounds
   Based on Deep Research Engine shared.css
   =================================================================== */

/* --- Design Tokens (customized for ai-vs-human-game) -------------- */
:root {
  /* Backgrounds */
  --c-bg:            #0a0a0f;
  --c-bg-alt:        #111118;
  --c-bg-card:       #1a1a24;
  --c-bg-lift:       #22222e;

  /* Text — warm off-white */
  --c-parchment:     #e8e4e0;
  --c-parchment-dim: #9090a0;

  /* Human side — warm amber/gold */
  --c-gold:          #e8a838;
  --c-gold-dim:      #a07020;
  --c-gold-soft:     rgba(232,168,56,0.08);

  /* AI side — cool cyan */
  --c-teal:          #38d4e8;
  --c-teal-dim:      #2090a0;

  /* Tension / collision zone */
  --c-amber:         #e84060;
  --c-tension:       #e84060;

  /* Borders */
  --c-border:        rgba(232,168,56,0.15);
  --c-border-strong: rgba(232,168,56,0.35);

  /* Typography — Space Grotesk for headings, Inter for body, JetBrains Mono for data */
  --f-title:  'Space Grotesk', sans-serif;
  --f-body:   'Inter', sans-serif;
  --f-prose:  'Inter', sans-serif;
  --f-mono:   'JetBrains Mono', monospace;

  --radius:    6px;
  --radius-lg: 12px;
  --max-w:     960px;
}

/* --- Reset -------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background: var(--c-bg);
  color: var(--c-parchment);
  font-family: var(--f-body);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* --- Typography --------------------------------------------------- */
h1, h2, h3, h4 {
  font-family: var(--f-title);
  letter-spacing: 0.02em;
  line-height: 1.2;
}
h1 { font-size: clamp(2.2rem, 5vw, 3.8rem); font-weight: 700; color: var(--c-parchment); }
h2 { font-size: clamp(1.5rem, 2.8vw, 2rem);  font-weight: 600; color: var(--c-gold); }
h3 { font-size: 1.1rem; font-weight: 600; color: var(--c-parchment); }
h4 { font-size: 0.95rem; font-weight: 600; color: var(--c-gold); letter-spacing: 0.06em; }

p {
  font-family: var(--f-prose);
  font-size: 1.08rem;
  color: var(--c-parchment-dim);
  line-height: 1.75;
}
p + p { margin-top: 1rem; }
strong { color: var(--c-parchment); font-weight: 600; }
em { color: var(--c-parchment); }

a { color: var(--c-teal); text-decoration: none; }
a:hover { color: var(--c-gold); }

/* --- Layout ------------------------------------------------------- */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 2rem;
}
section { padding: 5rem 0; }
section + section { border-top: 1px solid var(--c-border); }

/* --- Navigation --------------------------------------------------- */
.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(10,10,15,0.88);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--c-border);
}
.nav-logo {
  font-family: var(--f-title);
  font-size: 0.85rem;
  letter-spacing: 0.10em;
  color: var(--c-gold);
  text-transform: uppercase;
  text-decoration: none;
}
.nav-links { display: flex; gap: 1.75rem; list-style: none; }
.nav-links a {
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--c-parchment-dim);
  text-decoration: none;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--c-gold); }

/* --- Nav right group (nav-links + lang-switcher) ------------------ */
.nav-right {
  display: flex;
  align-items: center;
  gap: 2rem;
}

/* --- Language switcher -------------------------------------------- */
.lang-switcher {
  display: flex;
  align-items: center;
  gap: 0.15rem;
  border-left: 1px solid var(--c-border);
  padding-left: 1.25rem;
}
.lang-btn {
  font-family: var(--f-body);
  font-size: 0.62rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-parchment-dim);
  text-decoration: none;
  padding: 0.2rem 0.45rem;
  border-radius: 3px;
  transition: color 0.2s, background 0.2s;
}
.lang-btn:hover { color: var(--c-parchment); background: rgba(255,255,255,0.05); }
.lang-btn.lang-active {
  color: var(--c-gold);
  background: rgba(232,168,56,0.08);
}

/* --- Breadcrumb --------------------------------------------------- */
.breadcrumb {
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--c-parchment-dim);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 2rem;
  padding-top: 6rem;
}
.breadcrumb a { color: var(--c-gold-dim); text-decoration: none; }
.breadcrumb a:hover { color: var(--c-gold); }
.breadcrumb-sep { opacity: 0.4; }

/* --- Page Header (for research pages) ----------------------------- */
.page-header {
  padding: 2rem 0 4rem;
  border-bottom: 1px solid var(--c-border);
  margin-bottom: 4rem;
}
.page-header-eyebrow {
  font-family: var(--f-mono);
  font-size: 0.68rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--c-teal-dim);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.page-header-eyebrow::before {
  content: '';
  display: inline-block;
  width: 1.5rem;
  height: 1px;
  background: var(--c-teal);
}
.page-subtitle {
  font-family: var(--f-prose);
  font-size: 1.2rem;
  font-style: italic;
  color: var(--c-parchment-dim);
  margin-top: 1rem;
  max-width: 65ch;
}

/* --- Research Hero Image ------------------------------------------ */
.research-hero {
  max-width: var(--max-w);
  margin: 0 auto 3rem;
  padding: 0 1.5rem;
}
.research-hero img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--c-border);
  display: block;
}

/* --- Section Header ----------------------------------------------- */
.section-header { margin-bottom: 2.5rem; }
.section-eyebrow {
  font-family: var(--f-mono);
  font-size: 0.68rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--c-gold-dim);
  margin-bottom: 0.6rem;
}

/* --- Cards -------------------------------------------------------- */
.card {
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: border-color 0.25s, transform 0.25s;
}
.card:hover { border-color: var(--c-border-strong); transform: translateY(-2px); }

/* --- Callout ------------------------------------------------------ */
.callout {
  border-left: 3px solid var(--c-gold);
  padding: 1.25rem 1.75rem;
  background: rgba(232,168,56,0.06);
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 2rem 0;
}
.callout p { font-size: 1.05rem; color: var(--c-parchment); max-width: none; }
.callout-teal {
  border-left-color: var(--c-teal);
  background: rgba(56,212,232,0.06);
}
.callout-amber {
  border-left-color: var(--c-tension);
  background: rgba(232,64,96,0.06);
}

/* --- Pull quote --------------------------------------------------- */
.pull-quote {
  font-family: var(--f-title);
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  color: var(--c-gold);
  line-height: 1.4;
  padding: 2rem 0;
  border-top: 1px solid var(--c-border);
  border-bottom: 1px solid var(--c-border);
  margin: 2.5rem 0;
  letter-spacing: 0.01em;
}

/* --- Grids -------------------------------------------------------- */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.25rem; }
.grid-auto { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1.25rem; }
@media (max-width: 700px) {
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .site-nav .nav-links { display: none; }
}

/* --- Tag pills ---------------------------------------------------- */
.tag {
  display: inline-block;
  font-family: var(--f-mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  font-weight: 500;
}
.tag-gold  { background: rgba(232,168,56,0.12); color: var(--c-gold);  border: 1px solid rgba(232,168,56,0.3); }
.tag-teal  { background: rgba(56,212,232,0.12); color: var(--c-teal);  border: 1px solid rgba(56,212,232,0.3); }
.tag-amber { background: rgba(232,64,96,0.12);  color: var(--c-tension); border: 1px solid rgba(232,64,96,0.3); }

/* --- Images ------------------------------------------------------- */
.full-image {
  width: 100%;
  border-radius: var(--radius-lg);
  border: 1px solid var(--c-border);
  display: block;
  margin: 2.5rem 0;
}
.full-image.no-margin { margin: 0; }

/* --- Cover (home page) -------------------------------------------- */
.cover {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: flex-end;
  overflow: hidden;
}
.cover-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center top;
  filter: brightness(0.42);
}
.cover-gradient {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    to bottom,
    rgba(10,10,15,0.15) 0%,
    rgba(10,10,15,0.0)  35%,
    rgba(10,10,15,0.65) 70%,
    rgba(10,10,15,1.0)  100%
  );
}
.cover-content {
  position: relative;
  z-index: 2;
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 2rem 7rem;
}
.cover-eyebrow {
  font-family: var(--f-mono);
  font-size: 0.7rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--c-teal);
  margin-bottom: 1.2rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.cover-eyebrow::before {
  content: '';
  display: inline-block;
  width: 2rem; height: 1px;
  background: var(--c-teal);
}
.cover-tagline {
  font-family: var(--f-prose);
  font-size: 1.2rem;
  font-style: italic;
  color: var(--c-parchment-dim);
  margin: 1rem 0 2.5rem;
  max-width: 55ch;
}
.cover-meta { display: flex; gap: 3rem; flex-wrap: wrap; }
.meta-item { display: flex; flex-direction: column; gap: 0.2rem; }
.meta-label {
  font-family: var(--f-mono);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-teal-dim);
}
.meta-value {
  font-family: var(--f-title);
  font-size: 0.88rem;
  color: var(--c-parchment);
}

/* --- Stats -------------------------------------------------------- */
.stat-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  padding: 2rem 0;
  border-top: 1px solid var(--c-border);
  border-bottom: 1px solid var(--c-border);
  margin: 2.5rem 0;
}
.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  flex: 1;
  min-width: 100px;
}
.stat-value {
  font-family: var(--f-mono);
  font-size: 2rem;
  color: var(--c-gold);
  line-height: 1;
}
.stat-value.cyan { color: var(--c-teal); }
.stat-label {
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--c-parchment-dim);
  margin-top: 0.4rem;
}

/* --- Research card (index page) ----------------------------------- */
.research-card {
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  position: relative;
  overflow: hidden;
  transition: border-color 0.25s, transform 0.2s;
  display: flex;
  flex-direction: column;
  cursor: pointer;
}
.research-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 3px; height: 100%;
  background: linear-gradient(to bottom, var(--c-gold), var(--c-teal));
}
.research-card:hover { border-color: var(--c-border-strong); transform: translateY(-2px); }
.research-num {
  font-family: var(--f-mono);
  font-size: 0.65rem;
  letter-spacing: 0.18em;
  color: var(--c-teal-dim);
  margin-bottom: 0.5rem;
}
.research-title {
  font-family: var(--f-title);
  font-size: 0.95rem;
  color: var(--c-parchment);
  margin-bottom: 0.75rem;
}
.research-intro {
  font-family: var(--f-prose);
  font-size: 0.98rem;
  color: var(--c-parchment-dim);
  line-height: 1.65;
  flex: 1;
}
.research-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  margin-top: 1.25rem;
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--c-teal);
  text-decoration: none;
  transition: color 0.2s, gap 0.2s;
}
.research-link:hover { color: var(--c-gold); gap: 0.65rem; }

/* --- Pillar ------------------------------------------------------- */
.pillar {
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  transition: border-color 0.25s, background 0.25s;
}
.pillar:hover { border-color: var(--c-border-strong); background: var(--c-bg-lift); }
.pillar-num {
  font-family: var(--f-mono);
  font-size: 1.8rem;
  color: rgba(232,168,56,0.2);
  line-height: 1;
}
.pillar-title {
  font-family: var(--f-title);
  font-size: 0.88rem;
  color: var(--c-parchment);
  letter-spacing: 0.04em;
}
.pillar-body {
  font-family: var(--f-prose);
  font-size: 0.92rem;
  color: var(--c-parchment-dim);
  line-height: 1.55;
}

/* --- Gap cards ---------------------------------------------------- */
.gap-card {
  background: var(--c-bg-card);
  border: 1px solid rgba(232,64,96,0.2);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  display: flex; gap: 0.75rem; align-items: flex-start;
  margin: 1rem 0;
}
.gap-icon { color: var(--c-tension); font-size: 0.8rem; margin-top: 0.2rem; flex-shrink: 0; }
.gap-text { font-family: var(--f-prose); font-size: 0.96rem; color: var(--c-parchment-dim); }

/* --- Gold rule ---------------------------------------------------- */
.gold-rule {
  display: flex; align-items: center; gap: 1rem;
  margin: 3rem 0;
}
.gold-rule::before, .gold-rule::after {
  content: ''; flex: 1; height: 1px;
  background: linear-gradient(to right, var(--c-gold), var(--c-teal));
  opacity: 0.35;
}
.gold-rule-icon { width: 8px; height: 8px; background: var(--c-gold); transform: rotate(45deg); flex-shrink: 0; }

/* --- Research page bottom navigation ------------------------------ */
.research-page-nav {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1.5rem;
  padding: 2.5rem 0;
  border-top: 1px solid var(--c-border);
  margin-top: 4rem;
}

.rpn-prev,
.rpn-next {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  text-decoration: none;
  padding: 1rem 1.25rem;
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  background: var(--c-bg-card);
  transition: border-color 0.2s, background 0.2s;
  cursor: pointer;
}
.rpn-prev:hover,
.rpn-next:hover {
  border-color: var(--c-border-strong);
  background: var(--c-bg-lift);
}
.rpn-prev { align-items: flex-start; }
.rpn-next { align-items: flex-end; text-align: right; }

.rpn-label {
  font-size: 0.65rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--c-teal-dim);
  font-family: var(--f-mono);
}
.rpn-title {
  font-family: var(--f-title);
  font-size: 0.88rem;
  color: var(--c-parchment);
  letter-spacing: 0.03em;
}

.rpn-home {
  text-align: center;
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-teal-dim);
  text-decoration: none;
  padding: 0.6rem 1rem;
  border: 1px solid var(--c-border);
  border-radius: 999px;
  white-space: nowrap;
  transition: color 0.2s, border-color 0.2s;
  font-family: var(--f-mono);
  cursor: pointer;
}
.rpn-home:hover { color: var(--c-gold); border-color: var(--c-border-strong); }

.rpn-empty { visibility: hidden; pointer-events: none; }

@media (max-width: 600px) {
  .research-page-nav { grid-template-columns: 1fr 1fr; }
  .rpn-home { grid-column: 1 / -1; order: -1; }
}

/* --- Font Size Widget --------------------------------------------- */
.font-size-widget {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 99;
  display: flex;
  gap: 0.25rem;
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  border-radius: 999px;
  padding: 0.35rem 0.5rem;
  backdrop-filter: blur(8px);
}
.font-size-btn {
  width: 2rem; height: 2rem;
  border: 1px solid var(--c-border);
  border-radius: 50%;
  background: transparent;
  color: var(--c-parchment-dim);
  font-family: var(--f-body);
  font-size: 0.75rem;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
}
.font-size-btn:hover {
  color: var(--c-gold);
  border-color: var(--c-gold-dim);
  background: rgba(232,168,56,0.08);
}
.font-size-btn.active {
  color: var(--c-gold);
  border-color: var(--c-gold);
  background: rgba(232,168,56,0.12);
}

/* Font size scale classes on <html> */
html.font-sm  { font-size: 14px; }
html.font-md  { font-size: 16px; }
html.font-lg  { font-size: 18px; }

/* --- Footer ------------------------------------------------------- */
footer {
  padding: 3rem 2rem;
  border-top: 1px solid var(--c-border);
  text-align: center;
}
.footer-logo {
  font-family: var(--f-title);
  font-size: 0.82rem;
  letter-spacing: 0.15em;
  color: var(--c-gold-dim);
  margin-bottom: 0.5rem;
}
footer p {
  font-size: 0.78rem;
  color: var(--c-parchment-dim);
  opacity: 0.45;
  text-align: center;
  max-width: none;
}

/* --- Deep page prose sections ------------------------------------- */
.prose-section {
  max-width: 72ch;
  margin: 2.5rem auto 3.5rem;
}
.prose-section p + p { margin-top: 1.1rem; }

/* --- Insight block ------------------------------------------------ */
.insight-block {
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  border-left: 3px solid var(--c-teal);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin: 2rem 0;
}
.insight-block h3 { margin-bottom: 1rem; color: var(--c-teal); }
.insight-block p { max-width: 72ch; }

/* --- Application block -------------------------------------------- */
.application-block {
  border-left: 3px solid var(--c-teal);
  padding: 1rem 1.5rem;
  background: rgba(56,212,232,0.05);
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1.5rem 0;
}
.application-block p { color: var(--c-parchment); max-width: none; }

/* --- Blockquote --------------------------------------------------- */
blockquote {
  border-left: 3px solid var(--c-gold-dim);
  padding: 1rem 1.5rem;
  margin: 1.5rem 0;
  background: rgba(232,168,56,0.04);
  border-radius: 0 var(--radius) var(--radius) 0;
}
blockquote p { color: var(--c-parchment); font-style: italic; }
blockquote small { color: var(--c-parchment-dim); font-size: 0.85rem; }

/* --- Duality divider (amber to cyan) ------------------------------ */
.duality-rule {
  height: 2px;
  border: none;
  margin: 3rem 0;
  background: linear-gradient(to right, var(--c-gold), var(--c-teal));
  opacity: 0.3;
}