/* ═══════════════════════════════════════════════════════════════
   GEXBoard — Content Pages Design System
   Used by: /learn, /guide and all article pages
   ═══════════════════════════════════════════════════════════════ */

:root {
  --bg: #07090F;
  --surface: #0D1117;
  --elevated: #161B22;
  --border: rgba(255,255,255,0.08);
  --brand: #00C896;
  --positive: #00C896;
  --negative: #FF4466;
  --warning: #FFAA00;
  --text: #E6EDF3;
  --text-2: #8B949E;
  --text-3: #484F58;
  --mono: 'JetBrains Mono', monospace;
  --ui: 'Space Grotesk', sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

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

/* ── NAV (identical to landing.html) ─────────────────────────── */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(7,9,15,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  flex-shrink: 0;
}

.nav-wordmark { display: flex; align-items: baseline; gap: 1px; font-weight: 700; font-size: 15px; letter-spacing: 0.04em; }
.nav-wordmark .gex { color: var(--brand); }
.nav-wordmark .board { color: var(--text); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  margin-left: auto;
}

.nav-links a {
  color: var(--text-2);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.15s;
}
.nav-links a:hover { color: var(--text); }
.nav-links a.active { color: var(--brand); }

.nav-cta-link {
  background: var(--brand) !important;
  color: var(--bg) !important;
  padding: 7px 16px !important;
  border-radius: 6px !important;
  font-weight: 700 !important;
  font-size: 13px !important;
  transition: opacity 0.15s !important;
}
.nav-cta-link:hover { opacity: 0.88 !important; }

.nav-hamburger {
  display: none;
  background: none;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 10px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 18px;
  margin-left: auto;
}

@media (max-width: 768px) {
  .nav-hamburger { display: block; }
  .nav-links {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    align-items: flex-start;
    padding: 16px 24px;
    gap: 16px;
  }
  .nav-links.nav-links--open { display: flex; }
}

/* ── PAGE LAYOUT ──────────────────────────────────────────────── */
.content-wrapper {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: 1fr 200px;
  grid-template-areas: "article toc";
  gap: 48px;
  align-items: start;
}

.content-wrapper.no-toc {
  grid-template-columns: 1fr;
  grid-template-areas: "article";
  max-width: 800px;
}

article {
  grid-area: article;
  min-width: 0;
}

@media (max-width: 960px) {
  .content-wrapper {
    grid-template-columns: 1fr;
    grid-template-areas: "article";
  }
  .toc-sidebar { display: none; }
}

/* ── BREADCRUMBS ──────────────────────────────────────────────── */
.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-3);
  padding: 24px 0 0;
  flex-wrap: wrap;
}
.breadcrumbs a { color: var(--text-2); text-decoration: none; }
.breadcrumbs a:hover { color: var(--brand); }
.breadcrumbs .sep { color: var(--text-3); }

/* ── ARTICLE HERO ─────────────────────────────────────────────── */
.article-hero {
  padding: 32px 0 40px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 40px;
}

.eyebrow {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--brand);
  background: rgba(0,217,255,0.08);
  border: 1px solid rgba(0,217,255,0.2);
  padding: 4px 10px;
  border-radius: 4px;
  margin-bottom: 16px;
}

.article-hero h1 {
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 700;
  line-height: 1.15;
  color: var(--text);
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 13px;
  color: var(--text-3);
  flex-wrap: wrap;
}
.article-meta .sep { color: var(--border); }

/* ── TL;DR BOX ────────────────────────────────────────────────── */
.tldr {
  background: var(--elevated);
  border: 1px solid var(--border);
  border-left: 3px solid var(--brand);
  border-radius: 8px;
  padding: 20px 24px;
  margin: 0 0 40px;
}
.tldr-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--brand);
  margin-bottom: 10px;
}
.tldr p { color: var(--text-2); font-size: 15px; margin: 0; }
.tldr ul { color: var(--text-2); font-size: 15px; padding-left: 20px; margin: 0; }
.tldr ul li { margin-bottom: 4px; }

/* ── PROSE ────────────────────────────────────────────────────── */
.prose h2 {
  font-size: clamp(20px, 2.5vw, 26px);
  font-weight: 700;
  color: var(--text);
  margin: 48px 0 16px;
  letter-spacing: -0.01em;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.prose h3 {
  font-size: 18px;
  font-weight: 600;
  color: var(--text);
  margin: 32px 0 12px;
}

.prose p {
  color: var(--text-2);
  margin-bottom: 18px;
  font-size: 16px;
}

.prose strong { color: var(--text); font-weight: 600; }

.prose em { font-style: italic; color: var(--text-2); }

.prose ul, .prose ol {
  color: var(--text-2);
  padding-left: 24px;
  margin-bottom: 18px;
}
.prose ul li, .prose ol li { margin-bottom: 6px; }

.prose blockquote {
  border-left: 3px solid var(--brand);
  padding: 12px 20px;
  margin: 24px 0;
  background: var(--elevated);
  border-radius: 0 6px 6px 0;
  color: var(--text-2);
  font-style: italic;
}

.prose code {
  font-family: var(--mono);
  font-size: 13px;
  background: var(--elevated);
  border: 1px solid var(--border);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--brand);
}

.prose pre {
  background: var(--elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px 24px;
  overflow-x: auto;
  margin-bottom: 24px;
}
.prose pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: 14px;
  color: var(--text);
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 24px;
  font-size: 14px;
}
.prose table th {
  background: var(--elevated);
  color: var(--text);
  font-weight: 600;
  padding: 10px 14px;
  text-align: left;
  border: 1px solid var(--border);
}
.prose table td {
  padding: 10px 14px;
  border: 1px solid var(--border);
  color: var(--text-2);
}
.prose table tr:nth-child(even) td { background: rgba(255,255,255,0.02); }

.prose a {
  color: var(--brand);
  text-decoration: none;
}
.prose a:hover { text-decoration: underline; }

/* ── CALLOUT BOXES ────────────────────────────────────────────── */
.callout-tip,
.callout-warning,
.callout-important {
  border-radius: 8px;
  padding: 16px 20px;
  margin: 24px 0;
  font-size: 15px;
  display: flex;
  gap: 12px;
}

.callout-tip {
  background: rgba(0,200,150,0.08);
  border: 1px solid rgba(0,200,150,0.25);
  color: var(--text-2);
}
.callout-tip .callout-icon { color: var(--positive); flex-shrink: 0; font-style: normal; }

.callout-warning {
  background: rgba(255,170,0,0.08);
  border: 1px solid rgba(255,170,0,0.25);
  color: var(--text-2);
}
.callout-warning .callout-icon { color: var(--warning); flex-shrink: 0; font-style: normal; }

.callout-important {
  background: rgba(255,68,102,0.08);
  border: 1px solid rgba(255,68,102,0.25);
  color: var(--text-2);
}
.callout-important .callout-icon { color: var(--negative); flex-shrink: 0; font-style: normal; }

/* ── INLINE CTA CARD ──────────────────────────────────────────── */
.cta-card {
  background: var(--elevated);
  border: 1px solid rgba(0,217,255,0.25);
  border-radius: 12px;
  padding: 28px 32px;
  margin: 40px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}

.cta-card-text h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  margin: 0 0 6px;
}
.cta-card-text p {
  color: var(--text-2);
  font-size: 14px;
  margin: 0;
}

.cta-btn {
  display: inline-block;
  background: var(--brand);
  color: var(--bg);
  font-family: var(--ui);
  font-size: 14px;
  font-weight: 700;
  padding: 12px 24px;
  border-radius: 8px;
  text-decoration: none;
  white-space: nowrap;
  transition: opacity 0.15s;
  flex-shrink: 0;
}
.cta-btn:hover { opacity: 0.88; }

/* ── RELATED ARTICLES GRID ────────────────────────────────────── */
.related-section {
  margin-top: 64px;
  padding-top: 40px;
  border-top: 1px solid var(--border);
}

.related-section h2 {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 24px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
}

.related-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 20px;
  text-decoration: none;
  transition: border-color 0.15s, transform 0.15s;
  display: block;
}
.related-card:hover {
  border-color: rgba(0,217,255,0.3);
  transform: translateY(-2px);
}
.related-card .rc-eyebrow {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--brand);
  margin-bottom: 8px;
}
.related-card h3 {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.4;
}

/* ── FAQ ACCORDION ────────────────────────────────────────────── */
.faq-section {
  margin-top: 48px;
}
.faq-section h2 {
  font-size: clamp(20px, 2.5vw, 26px);
  font-weight: 700;
  color: var(--text);
  margin-bottom: 24px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 8px;
  overflow: hidden;
}

.faq-item summary {
  list-style: none;
  padding: 16px 20px;
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  color: var(--brand);
  font-size: 20px;
  font-weight: 300;
  flex-shrink: 0;
  transition: transform 0.2s;
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item[open] { border-color: rgba(0,217,255,0.2); }
.faq-item[open] summary { color: var(--brand); }

.faq-answer {
  padding: 0 20px 20px;
  color: var(--text-2);
  font-size: 15px;
  line-height: 1.7;
}
.faq-answer p { margin-bottom: 8px; }
.faq-answer p:last-child { margin-bottom: 0; }

/* ── SHARE BUTTONS ────────────────────────────────────────────── */
.share-section {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
}
.share-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-3);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.share-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: var(--ui);
  font-size: 13px;
  font-weight: 500;
  color: var(--text-2);
  background: var(--elevated);
  cursor: pointer;
  text-decoration: none;
  transition: border-color 0.15s, color 0.15s;
}
.share-btn:hover { border-color: var(--brand); color: var(--brand); }

/* ── SIDEBAR TOC ──────────────────────────────────────────────── */
.toc-sidebar {
  grid-area: toc;
  position: sticky;
  top: 80px;
  font-size: 13px;
}

.toc-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 12px;
}

.toc-list {
  list-style: none;
  padding: 0;
  border-left: 1px solid var(--border);
}
.toc-list li a {
  display: block;
  padding: 5px 0 5px 14px;
  color: var(--text-3);
  text-decoration: none;
  line-height: 1.4;
  transition: color 0.15s, border-color 0.15s;
  border-left: 2px solid transparent;
  margin-left: -1px;
}
.toc-list li a:hover,
.toc-list li a.active {
  color: var(--brand);
  border-left-color: var(--brand);
}

/* ── HUB INDEX PAGE ───────────────────────────────────────────── */
.hub-hero {
  text-align: center;
  padding: 72px 24px 56px;
  max-width: 680px;
  margin: 0 auto;
}
.hub-hero h1 {
  font-size: clamp(32px, 5vw, 52px);
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.03em;
  margin-bottom: 16px;
  line-height: 1.1;
}
.hub-hero p {
  font-size: 18px;
  color: var(--text-2);
  line-height: 1.6;
}

.hub-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px 80px;
}

.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.hub-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px;
  text-decoration: none;
  display: block;
  transition: border-color 0.15s, transform 0.15s, box-shadow 0.15s;
}
.hub-card:hover {
  border-color: rgba(0,217,255,0.3);
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
}

.hub-card-badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--brand);
  background: rgba(0,217,255,0.08);
  border: 1px solid rgba(0,217,255,0.2);
  padding: 3px 8px;
  border-radius: 4px;
  margin-bottom: 14px;
}

.hub-card h2 {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
  line-height: 1.35;
}

.hub-card p {
  font-size: 14px;
  color: var(--text-2);
  line-height: 1.6;
  margin: 0;
}

.hub-card-arrow {
  display: inline-block;
  margin-top: 16px;
  font-size: 13px;
  color: var(--brand);
  font-weight: 600;
}

/* ── FORMULA BOX ──────────────────────────────────────────────── */
.formula-box {
  background: var(--elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px;
  margin: 24px 0;
  text-align: center;
}
.formula-box .formula-main {
  font-family: var(--mono);
  font-size: 18px;
  color: var(--text);
  margin-bottom: 12px;
}
.formula-box .formula-note {
  font-size: 13px;
  color: var(--text-3);
}

/* ── FOOTER (identical to landing.html) ──────────────────────── */
footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  margin-top: 80px;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 56px 24px 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

@media (max-width: 768px) {
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
}

.footer-brand { display: flex; align-items: center; gap: 10px; margin-bottom: 16px; }
.footer-brand-name { display: flex; align-items: baseline; gap: 1px; font-weight: 700; font-size: 15px; letter-spacing: 0.04em; }
.footer-brand-name .gex { color: var(--brand); }
.footer-brand-name .board { color: var(--text); }
.footer-tagline { font-size: 14px; color: var(--text-3); margin-bottom: 20px; }

.footer-socials { display: flex; gap: 12px; }
.footer-socials a { color: var(--text-3); transition: color 0.15s; }
.footer-socials a:hover { color: var(--brand); }
.footer-socials svg { width: 20px; height: 20px; fill: currentColor; }

.footer-col-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 16px;
}
.footer-links { display: flex; flex-direction: column; gap: 10px; }
.footer-links a { font-size: 14px; color: var(--text-2); text-decoration: none; transition: color 0.15s; }
.footer-links a:hover { color: var(--brand); }

.footer-disclaimer {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  font-size: 12px;
  color: var(--text-3);
  line-height: 1.6;
}

.footer-nfa {
  margin-top: 16px;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-3);
  opacity: 0.5;
}

/* ── IMG PLACEHOLDER ──────────────────────────────────────────── */
.img-placeholder {
  background: var(--elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  height: 300px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-3);
  font-family: var(--mono);
  font-size: 13px;
  margin: 24px 0;
}

/* ── MOBILE RESPONSIVE ────────────────────────────────────────── */
@media (max-width: 768px) {
  .hub-hero { padding: 48px 24px 40px; }
  .hub-hero h1 { font-size: 32px; }

  .cta-card {
    flex-direction: column;
    align-items: flex-start;
  }

  .share-section { gap: 8px; }

  .article-hero { padding: 24px 0 32px; }

  .content-wrapper { padding: 0 16px; }
  .hub-container { padding: 0 16px 60px; }

  .related-grid { grid-template-columns: 1fr; }
}