:root {
  --bg: #0b0d0f;
  --bg-alt: #14171a;
  --text: #f4f7f4;
  --muted: #b7c0c8;
  --accent: #f7c948;
  --accent-text: #14171a;
  --card: #1e2226;
  --border: #34393f;
  --radius-lg: 20px;
  --radius-full: 999px;
  --max-width: 1080px;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f4f7f4;
    --bg-alt: #ffffff;
    --text: #14171a;
    --muted: #5b6470;
    --card: #ffffff;
    --border: #e3e7ea;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.55;
}

a { color: inherit; }

.wrap { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }

/* Nav */
.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}

.nav-brand { font-weight: 800; letter-spacing: 0.04em; text-decoration: none; }

.nav-links { display: flex; align-items: center; gap: 20px; font-size: 0.9rem; }
.nav-links a { text-decoration: none; color: var(--muted); }
.nav-links a:hover { color: var(--text); }
.nav-cta {
  background: var(--accent);
  color: var(--accent-text) !important;
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-weight: 700;
  white-space: nowrap;
}

@media (max-width: 640px) {
  .nav { padding: 14px 16px; }
  .nav-links { gap: 12px; }
  .nav-links a:not(.nav-cta) { display: none; }
  .nav-cta { padding: 7px 14px; font-size: 0.85rem; }
}

/* Hero */
.hero { padding: 64px 24px 48px; text-align: center; }
.hero-inner { max-width: 640px; margin: 0 auto; }

.avatar {
  width: 112px;
  height: 112px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--accent);
  background: #333;
  display: block;
  margin: 0 auto 24px;
}

h1 { font-size: 2.4rem; margin: 0 0 16px; }

.tagline { color: var(--muted); margin: 0 auto 28px; max-width: 480px; font-size: 1.05rem; }

.hero-actions { display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; margin-bottom: 28px; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 14px 24px;
  border-radius: var(--radius-full);
  border: 2px solid var(--border);
  background: var(--card);
  color: var(--text);
  text-decoration: none;
  font-weight: 700;
}

.btn-accent { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }
.btn-ghost { background: transparent; }

.socials { display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; }

.social {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  font-weight: 700;
  color: var(--accent-text);
  border: 2px solid var(--border);
}

.social.youtube { background: #ff6b9d; }
.social.instagram { background: #f7c948; }
.social.x { background: #b8a9f0; }
.social.linkedin { background: #2fd0bc; }
.social.github { background: #8fd0ff; font-size: 0.85rem; }

main { max-width: var(--max-width); margin: 0 auto; padding: 0 24px 64px; }

.section { margin-top: 72px; }

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 24px;
  flex-wrap: wrap;
  gap: 8px;
}

.section-title {
  font-size: 1.6rem;
  margin: 0 0 24px;
}
.section-head .section-title { margin-bottom: 0; }

.see-all { color: var(--accent); text-decoration: none; font-weight: 700; font-size: 0.95rem; white-space: nowrap; }

.grid { display: grid; gap: 20px; }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }

@media (max-width: 900px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .grid-4, .grid-3 { grid-template-columns: 1fr; }
  h1 { font-size: 1.9rem; }
}

/* Help cards */
.help-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.15s ease, border-color 0.15s ease;
}
.help-card:hover { transform: translateY(-4px); border-color: var(--accent); }
.help-icon { font-size: 2rem; display: block; margin-bottom: 12px; }
.help-card h3 { margin: 0 0 8px; font-size: 1.05rem; }
.help-card p { margin: 0 0 16px; color: var(--muted); font-size: 0.92rem; }
.help-link { color: var(--accent); font-weight: 700; font-size: 0.9rem; }

/* Subscribe */
.subscribe-section { margin-top: 72px; }
.subscribe-card {
  background: linear-gradient(135deg, var(--card), var(--bg-alt));
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 48px 32px;
  text-align: center;
}
.subscribe-card h2 { margin: 0 0 8px; font-size: 1.6rem; }
.subscribe-card p { color: var(--muted); margin: 0 0 24px; }

.substack-embed {
  max-width: 480px;
  width: 100%;
  border-radius: 12px;
  background: #fff;
}

/* Video cards */
.video-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.15s ease, border-color 0.15s ease;
}
.video-card:hover { transform: translateY(-4px); border-color: var(--accent); }
.video-card img { width: 100%; aspect-ratio: 16/9; object-fit: cover; display: block; }
.video-tag {
  display: block;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--accent);
  font-weight: 700;
  padding: 14px 16px 0;
}
.video-card h3 { margin: 6px 16px 16px; font-size: 0.98rem; }

/* Blog cards */
.blog-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.15s ease, border-color 0.15s ease;
}
.blog-card:hover { transform: translateY(-4px); border-color: var(--accent); }
.blog-icon { font-size: 1.6rem; display: block; margin-bottom: 10px; }
.blog-card h3 { margin: 0 0 8px; font-size: 1.02rem; }
.blog-card p { margin: 0 0 14px; color: var(--muted); font-size: 0.9rem; }
.tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tags span {
  font-size: 0.72rem;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  background: var(--bg-alt);
  border: 1px solid var(--border);
  color: var(--muted);
}

.tag-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}
.tag-pill {
  font: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  background: var(--card);
  border: 1px solid var(--border);
  color: var(--muted);
  cursor: pointer;
}
.tag-pill:hover { color: var(--text); border-color: var(--accent); }
.tag-pill.active { background: var(--accent); color: var(--accent-text); border-color: var(--accent); font-weight: 700; }

/* Talk cards */
.talk-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.15s ease, border-color 0.15s ease;
}
.talk-card:hover { transform: translateY(-4px); border-color: var(--accent); }
.talk-icon { font-size: 1.8rem; display: block; margin-bottom: 10px; }
.talk-card h3 { margin: 0 0 8px; font-size: 1.02rem; }
.talk-card p { margin: 0; color: var(--muted); font-size: 0.9rem; }

/* About */
.about-grid { display: grid; grid-template-columns: 200px 1fr; gap: 32px; align-items: start; }
@media (max-width: 700px) { .about-grid { grid-template-columns: 1fr; text-align: center; } }

.about-photo {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: #333;
}

.about-copy { grid-column: 2; }
@media (max-width: 700px) { .about-copy { grid-column: 1; } }

.about-copy p { color: var(--muted); margin: 0 0 16px; }
.about-copy blockquote {
  margin: 0 0 20px;
  padding: 14px 20px;
  border-left: 3px solid var(--accent);
  color: var(--text);
  font-style: italic;
  background: var(--card);
  border-radius: 0 12px 12px 0;
}
.profile-refs { display: flex; gap: 18px; flex-wrap: wrap; justify-content: flex-start; }
@media (max-width: 700px) { .profile-refs { justify-content: center; } }
.profile-refs a { font-weight: 700; text-decoration: underline; }

/* FAQ */
.faq details {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px 22px;
  margin-bottom: 12px;
}
.faq summary { font-weight: 700; cursor: pointer; }
.faq p { color: var(--muted); margin: 14px 0 0; }

.older-blogs { margin-top: 24px; }

/* Footer */
footer {
  text-align: center;
  padding: 48px 24px 32px;
  color: var(--muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
  margin-top: 72px;
}
footer .socials { margin-bottom: 20px; }

/* Blog post pages */
.post-main { max-width: 760px; margin: 0 auto; padding: 48px 24px 64px; }

.back-link {
  display: inline-block;
  margin-bottom: 20px;
  color: var(--accent);
  text-decoration: none;
  font-weight: 700;
  font-size: 0.9rem;
}

.post-icon { font-size: 2.2rem; display: block; margin-bottom: 8px; }

.post h1 { font-size: 2rem; margin: 0 0 16px; line-height: 1.25; }

.post-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 32px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}
.post-meta time { color: var(--muted); font-size: 0.9rem; }
.post-meta .tags { display: flex; gap: 6px; flex-wrap: wrap; }
.post-meta .tags span {
  font-size: 0.72rem;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  background: var(--card);
  border: 1px solid var(--border);
  color: var(--muted);
}

.post-body h2 { font-size: 1.35rem; margin: 40px 0 16px; }
.post-body h3 { font-size: 1.1rem; margin: 28px 0 12px; }
.post-body p { color: var(--muted); margin: 0 0 18px; }
.post-body strong { color: var(--text); }
.post-body a { color: var(--accent); }

.post-body ul, .post-body ol { color: var(--muted); padding-left: 22px; margin: 0 0 18px; }
.post-body li { margin-bottom: 8px; }

.post-body blockquote {
  margin: 0 0 20px;
  padding: 14px 20px;
  border-left: 3px solid var(--accent);
  color: var(--text);
  font-style: italic;
  background: var(--card);
  border-radius: 0 12px 12px 0;
}

.post-body code {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  font-size: 0.9em;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

.post-body pre {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px 20px;
  overflow-x: auto;
  margin: 0 0 20px;
}
.post-body pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: 0.85rem;
  line-height: 1.6;
}

.copy-btn {
  position: absolute;
  top: 10px;
  right: 10px;
  padding: 5px 12px;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  border: 1px solid var(--border);
  background: var(--bg-alt);
  color: var(--muted);
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s ease;
}
.post-body pre:hover .copy-btn { opacity: 1; }
.copy-btn:hover { color: var(--text); border-color: var(--accent); }

.post-image {
  margin: 0 0 24px;
}
.post-image img {
  width: 100%;
  border-radius: 12px;
  border: 1px solid var(--border);
  display: block;
}
.post-image figcaption {
  color: var(--muted);
  font-size: 0.85rem;
  text-align: center;
  margin-top: 8px;
}

.table-wrap { overflow-x: auto; margin: 0 0 20px; }
.post-body table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
.post-body th, .post-body td {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--muted);
}
.post-body th { color: var(--text); font-weight: 700; background: var(--card); }

/* JSON-rendered card grids (loading state) */
.grid[data-loading]::after {
  content: "Loading…";
  color: var(--muted);
  grid-column: 1 / -1;
}

/* Related posts (blog post pages) */
.related-posts {
  margin-top: 56px;
  padding-top: 40px;
  border-top: 1px solid var(--border);
}
.related-posts .grid-3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 700px) { .related-posts .grid-3 { grid-template-columns: 1fr; } }

.related-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 20px;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.15s ease, border-color 0.15s ease;
}
.related-card:hover { transform: translateY(-4px); border-color: var(--accent); }
.related-card .blog-icon { font-size: 1.4rem; display: block; margin-bottom: 8px; }
.related-card h3 { margin: 0; font-size: 0.95rem; }

/* DART Engineer Foundations — living document */
.doc-main { max-width: 1160px; margin: 0 auto; padding: 48px 24px 64px; }

.doc-back-link { display: block; }

.doc-header { max-width: 720px; margin: 0 0 32px; }
.doc-header h1 { font-size: 2rem; margin: 0 0 12px; line-height: 1.25; }
.doc-intro { color: var(--muted); margin: 0; }

.doc-toc-toggle {
  display: none;
  width: 100%;
  font: inherit;
  font-weight: 700;
  text-align: left;
  padding: 12px 16px;
  margin-bottom: 16px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--text);
  cursor: pointer;
}

.doc-layout {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 48px;
  align-items: start;
}

.doc-sidebar {
  position: sticky;
  top: 88px;
  max-height: calc(100vh - 120px);
  overflow-y: auto;
}
.doc-sidebar-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
  margin-bottom: 12px;
}
.doc-toc { display: flex; flex-direction: column; gap: 2px; }
.doc-toc-link {
  display: flex;
  flex-direction: column;
  padding: 8px 12px;
  border-radius: 10px;
  text-decoration: none;
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 600;
  border-left: 2px solid transparent;
}
.doc-toc-link span { font-weight: 400; font-size: 0.82rem; color: var(--muted); }
.doc-toc-link:hover { color: var(--text); background: var(--card); }
.doc-toc-link.active {
  color: var(--text);
  background: var(--card);
  border-left: 2px solid var(--accent);
}
.doc-toc-link.active span { color: var(--text); }

.doc-content { max-width: 720px; }
.doc-section { padding-bottom: 40px; margin-bottom: 40px; border-bottom: 1px solid var(--border); scroll-margin-top: 96px; }
.doc-section:last-child { border-bottom: none; margin-bottom: 0; }
.doc-section h2 { font-size: 1.5rem; margin: 0 0 20px; }
.doc-section h3 { font-size: 1.1rem; margin: 28px 0 12px; }
.doc-section p { color: var(--muted); margin: 0 0 18px; }
.doc-section strong { color: var(--text); }
.doc-section a { color: var(--accent); }
.doc-section ul, .doc-section ol { color: var(--muted); padding-left: 22px; margin: 0 0 18px; }
.doc-section li { margin-bottom: 8px; }
.doc-section blockquote {
  margin: 0 0 20px;
  padding: 14px 20px;
  border-left: 3px solid var(--accent);
  color: var(--text);
  font-style: italic;
  background: var(--card);
  border-radius: 0 12px 12px 0;
}
.doc-section code {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  font-size: 0.9em;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}
.doc-section pre {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px 20px;
  overflow-x: auto;
  margin: 0 0 20px;
}
.doc-section pre code { background: none; border: none; padding: 0; font-size: 0.85rem; line-height: 1.6; }
.doc-section table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
.doc-section th, .doc-section td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--border); color: var(--muted); }
.doc-section th { color: var(--text); font-weight: 700; background: var(--card); }

@media (max-width: 860px) {
  .doc-toc-toggle { display: block; }
  .doc-layout { grid-template-columns: 1fr; gap: 0; }
  .doc-sidebar {
    position: static;
    max-height: none;
    display: none;
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px;
    margin-bottom: 24px;
  }
  .doc-sidebar.open { display: block; }
}

/* 404 page */
.not-found {
  max-width: 480px;
  margin: 0 auto;
  padding: 120px 24px;
  text-align: center;
}
.not-found-icon { font-size: 2.5rem; display: block; margin-bottom: 20px; }
.not-found h1 { font-size: 1.8rem; margin: 0 0 12px; }
.not-found p { color: var(--muted); margin: 0 0 28px; }