/* Reply Engine Blog - Global Styles */
:root {
  --bg: #0a0e1a;
  --card: #0f1525;
  --card-border: #1a2240;
  --purple: #2563eb;
  --purple-light: #60a5fa;
  --cyan: #06b6d4;
  --cyan-light: #22d3ee;
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --white: #f8fafc;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --max-width: 820px;
  --nav-height: 64px;
}

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

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-height) + 24px); }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

/* Nav */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(10, 14, 26, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--card-border);
  height: var(--nav-height);
  display: flex; align-items: center;
}
.nav-inner {
  max-width: 1200px; width: 100%; margin: 0 auto;
  padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
  font-size: 22px; font-weight: 800; color: var(--white);
  text-decoration: none; letter-spacing: -0.5px;
}
.nav-logo span { color: var(--purple); }
.nav-links { display: flex; align-items: center; gap: 24px; }
.nav-links a {
  color: var(--text-muted); text-decoration: none; font-size: 14px; font-weight: 500;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--white); }
.nav-cta {
  background: var(--purple) !important; color: var(--white) !important;
  padding: 8px 18px !important; border-radius: 8px; font-weight: 600 !important;
  transition: background 0.2s !important;
}
.nav-cta:hover { background: #1d4ed8 !important; }

/* Article Layout */
.article-wrapper {
  max-width: 1200px; margin: 0 auto; padding: 40px 24px;
  display: flex; gap: 48px;
}
.article-main { flex: 1; min-width: 0; max-width: var(--max-width); }
.article-sidebar {
  width: 260px; flex-shrink: 0;
  position: sticky; top: calc(var(--nav-height) + 24px);
  align-self: flex-start; max-height: calc(100vh - var(--nav-height) - 48px);
  overflow-y: auto;
}
.toc { padding: 20px; background: var(--card); border-radius: 12px; border: 1px solid var(--card-border); }
.toc h4 { font-size: 12px; text-transform: uppercase; letter-spacing: 1px; color: var(--text-dim); margin-bottom: 12px; }
.toc a {
  display: block; padding: 4px 0; font-size: 13px; color: var(--text-muted);
  text-decoration: none; transition: color 0.2s;
}
.toc a:hover, .toc a.active { color: var(--cyan); }

/* Typography */
.article-main h1 {
  font-size: clamp(28px, 5vw, 40px); font-weight: 800; line-height: 1.2;
  color: var(--white); margin-bottom: 16px; letter-spacing: -0.5px;
}
.article-meta {
  display: flex; flex-wrap: wrap; gap: 16px; align-items: center;
  color: var(--text-dim); font-size: 14px; margin-bottom: 32px;
  padding-bottom: 24px; border-bottom: 1px solid var(--card-border);
}
.article-meta .author { color: var(--purple-light); font-weight: 600; }
.article-main h2 {
  font-size: 24px; font-weight: 700; color: var(--white);
  margin: 48px 0 16px; padding-top: 8px;
}
.article-main h3 {
  font-size: 19px; font-weight: 600; color: var(--white); margin: 32px 0 12px;
}
.article-main p { margin-bottom: 20px; color: var(--text); }
.article-main a { color: var(--cyan); text-decoration: none; }
.article-main a:hover { text-decoration: underline; }
.article-main ul, .article-main ol {
  margin: 0 0 20px 24px; color: var(--text);
}
.article-main li { margin-bottom: 8px; }
.article-main strong { color: var(--white); }
.article-main blockquote {
  border-left: 3px solid var(--purple); padding: 16px 20px; margin: 24px 0;
  background: var(--card); border-radius: 0 8px 8px 0;
  color: var(--text-muted); font-style: italic;
}

/* Definition Block */
.definition-block {
  background: var(--card); border: 1px solid var(--card-border);
  border-left: 4px solid var(--cyan); border-radius: 0 12px 12px 0;
  padding: 24px 28px; margin: 32px 0;
}
.definition-block h3 { margin-top: 0; color: var(--cyan); font-size: 16px; text-transform: uppercase; letter-spacing: 0.5px; }
.definition-block p { color: var(--text-muted); margin-bottom: 0; }

/* Framework Block */
.framework {
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.08), rgba(6, 182, 212, 0.08));
  border: 1px solid var(--card-border); border-radius: 12px;
  padding: 28px; margin: 32px 0;
}
.framework h3 { color: var(--purple-light); margin-top: 0; }
.framework ol { counter-reset: step; list-style: none; padding-left: 0; margin-left: 0; }
.framework ol li {
  counter-increment: step; padding-left: 36px; position: relative; margin-bottom: 16px;
}
.framework ol li::before {
  content: counter(step); position: absolute; left: 0; top: 2px;
  width: 24px; height: 24px; background: var(--purple); color: var(--white);
  border-radius: 50%; font-size: 13px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}

/* Tables */
.table-wrap { overflow-x: auto; margin: 24px 0; border-radius: 12px; border: 1px solid var(--card-border); }
table { width: 100%; border-collapse: collapse; min-width: 500px; }
th {
  background: var(--card); color: var(--purple-light); font-size: 13px;
  text-transform: uppercase; letter-spacing: 0.5px; font-weight: 600;
  padding: 14px 16px; text-align: left; white-space: nowrap;
}
td { padding: 12px 16px; border-top: 1px solid var(--card-border); font-size: 15px; color: var(--text-muted); }
tr:hover td { background: rgba(37, 99, 235, 0.04); }

/* Formula */
.formula-block {
  background: var(--card); border: 1px solid var(--card-border); border-radius: 12px;
  padding: 24px; margin: 24px 0; text-align: center;
}
.formula-block code {
  font-family: var(--font-mono); font-size: 16px; color: var(--cyan-light);
  display: block; margin-bottom: 12px;
}
.formula-block .weights {
  display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; margin-top: 12px;
}
.formula-block .weight {
  background: rgba(37, 99, 235, 0.15); border-radius: 8px; padding: 6px 14px;
  font-size: 13px; color: var(--text-muted);
}

/* FAQ */
.faq { margin: 32px 0; }
.faq details {
  background: var(--card); border: 1px solid var(--card-border); border-radius: 10px;
  margin-bottom: 8px; overflow: hidden;
}
.faq summary {
  padding: 16px 20px; cursor: pointer; font-weight: 600; color: var(--white);
  list-style: none; display: flex; align-items: center; justify-content: space-between;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: '+'; font-size: 20px; color: var(--purple); transition: transform 0.2s; }
.faq details[open] summary::after { content: '-'; }
.faq .faq-answer { padding: 0 20px 16px; color: var(--text-muted); }

/* Summary Box */
.summary-box {
  background: linear-gradient(135deg, rgba(6, 182, 212, 0.1), rgba(37, 99, 235, 0.1));
  border: 1px solid var(--card-border); border-radius: 12px;
  padding: 24px 28px; margin: 32px 0;
}
.summary-box h3 { color: var(--cyan); margin-top: 0; }
.summary-box ul { margin-bottom: 0; }

/* Prev/Next Nav */
.article-nav {
  display: flex; gap: 16px; margin-top: 48px; padding-top: 32px;
  border-top: 1px solid var(--card-border);
}
.article-nav a {
  flex: 1; display: block; padding: 20px; background: var(--card);
  border: 1px solid var(--card-border); border-radius: 12px;
  text-decoration: none; transition: border-color 0.2s;
}
.article-nav a:hover { border-color: var(--purple); }
.article-nav .label { font-size: 12px; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.5px; }
.article-nav .title { color: var(--white); font-weight: 600; margin-top: 4px; }
.article-nav .next { text-align: right; }

/* Share */
.share-buttons {
  display: flex; gap: 10px; margin: 32px 0;
}
.share-btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 16px; border-radius: 8px; font-size: 14px; font-weight: 500;
  text-decoration: none; transition: opacity 0.2s;
}
.share-btn:hover { opacity: 0.85; }
.share-btn.x { background: #000; color: #fff; border: 1px solid #333; }
.share-btn.linkedin { background: #0077b5; color: #fff; }

/* Blog Index */
.blog-hero {
  max-width: 1200px; margin: 0 auto; padding: 48px 24px 32px;
}
.blog-hero h1 { font-size: 36px; font-weight: 800; color: var(--white); }
.blog-hero p { color: var(--text-muted); font-size: 18px; margin-top: 8px; }

.blog-grid {
  max-width: 1200px; margin: 0 auto; padding: 0 24px 60px;
  display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: 20px;
}
.blog-card {
  background: var(--card); border: 1px solid var(--card-border); border-radius: 12px;
  padding: 24px; text-decoration: none; display: block; transition: border-color 0.2s, transform 0.2s;
}
.blog-card:hover { border-color: var(--purple); transform: translateY(-2px); }
.blog-card.featured {
  grid-column: 1 / -1;
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.12), rgba(6, 182, 212, 0.08));
  border-color: var(--purple);
}
.blog-card .card-label {
  font-size: 11px; text-transform: uppercase; letter-spacing: 1px;
  color: var(--purple-light); font-weight: 700; margin-bottom: 8px;
}
.blog-card h2 { font-size: 20px; color: var(--white); font-weight: 700; margin-bottom: 8px; line-height: 1.3; }
.blog-card.featured h2 { font-size: 26px; }
.blog-card p { color: var(--text-muted); font-size: 15px; line-height: 1.6; margin-bottom: 12px; }
.blog-card .card-meta { font-size: 13px; color: var(--text-dim); }

/* Repurpose Block */
.repurpose {
  background: var(--card); border: 1px solid var(--card-border); border-radius: 12px;
  padding: 24px 28px; margin: 32px 0;
}
.repurpose h3 { color: var(--purple-light); margin-top: 0; }
.repurpose h4 { color: var(--white); font-size: 16px; margin: 20px 0 8px; }
.repurpose:first-of-type h4 { margin-top: 12px; }

/* Not Block */
.not-block {
  background: rgba(239, 68, 68, 0.06); border: 1px solid rgba(239, 68, 68, 0.2);
  border-radius: 12px; padding: 24px 28px; margin: 32px 0;
}
.not-block h3 { color: #f87171; margin-top: 0; }

/* Responsive */
@media (max-width: 900px) {
  .article-sidebar { display: none; }
  .article-wrapper { padding: 24px 16px; }
  .article-nav { flex-direction: column; }
  .blog-grid { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  body { font-size: 16px; }
  .nav-inner { padding: 0 16px; }
  .nav-links { gap: 12px; }
  .nav-links a:not(.nav-cta) { display: none; }
  .article-main h1 { font-size: 26px; }
  .definition-block, .framework, .summary-box, .repurpose, .not-block { padding: 18px; }
  table { font-size: 14px; }
  th, td { padding: 10px 12px; }
}