/* ============================================================
   BAU AI Blog typography + layout
   Hanken Grotesk (sans/display) on cream/ink palette.
   Variables come from /styles/custom.css (:root).
   ============================================================ */

/* ---------- Article frame ---------- */
.blog-article {
  max-width: 720px;
  margin: 0 auto;
  padding: 4rem 1.5rem 6rem;
  font-family: var(--font-sans, 'Hanken Grotesk', system-ui, sans-serif);
  color: var(--ink);
}

/* ---------- Breadcrumb ---------- */
.breadcrumb-nav {
  margin-bottom: 2.5rem;
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  color: var(--muted);
}
.breadcrumb-nav ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
}
.breadcrumb-nav a {
  color: var(--muted);
  text-decoration: none;
  transition: color 0.15s ease;
}
.breadcrumb-nav a:hover { color: var(--ink); }
.breadcrumb-nav [aria-current="page"] {
  color: var(--ink);
  font-weight: 500;
  max-width: 28ch;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.breadcrumb-nav .separator { color: var(--muted-soft); }

/* ---------- Article header ---------- */
.article-header {
  margin-bottom: 2.5rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid var(--border);
}
.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 1.5rem;
}
.article-meta-sep { color: var(--muted-soft); }
.article-category a {
  color: var(--purple);
  text-decoration: none;
  font-weight: 500;
}
.article-category a:hover { text-decoration: underline; }

.article-title {
  font-family: var(--font-serif, 'Hanken Grotesk', system-ui, sans-serif);
  font-style: normal;
  font-weight: 400;
  font-size: clamp(2rem, 5vw, 3.5rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--ink);
  margin: 0 0 1.25rem;
}

.article-lead {
  font-size: 1.25rem;
  line-height: 1.55;
  color: var(--muted);
  margin: 0 0 1.5rem;
  max-width: 60ch;
}

.article-author {
  font-size: 0.875rem;
  color: var(--muted);
}
.article-author a {
  color: var(--ink);
  font-weight: 500;
  text-decoration: none;
  margin-left: 0.25rem;
}
.article-author a:hover { color: var(--purple); }

/* ---------- Hero image ---------- */
.article-hero {
  margin: 0 0 3rem;
  border-radius: 12px;
  overflow: hidden;
  background: var(--cream-dim);
}
.article-hero img,
.article-hero svg {
  display: block;
  width: 100%;
  height: auto;
}
.article-hero-svg,
.article-hero-image {
  aspect-ratio: 1200 / 540;
}
.article-hero-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

/* ---------- TOC ---------- */
.article-toc {
  background: var(--cream-dim);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.5rem 1.75rem;
  margin: 0 0 3rem;
}
.article-toc h2 {
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 0.875rem;
  font-weight: 500;
}
.article-toc ol, .article-toc ul {
  list-style: decimal;
  padding-left: 1.25rem;
  margin: 0;
}
.article-toc li {
  margin: 0.375rem 0;
  font-size: 0.9375rem;
  line-height: 1.5;
}
.article-toc a {
  color: var(--ink);
  text-decoration: none;
  transition: color 0.15s ease;
}
.article-toc a:hover { color: var(--purple); }

/* ---------- Article body ---------- */
.article-body {
  font-size: 1.125rem;
  line-height: 1.7;
  color: var(--ink);
}
.article-body > * + * { margin-top: 1.5rem; }

.article-body h2 {
  font-family: var(--font-sans, 'Hanken Grotesk', system-ui, sans-serif);
  font-style: normal;
  font-weight: 700;
  font-size: clamp(1.5rem, 2.8vw, 1.875rem);
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--ink);
  margin-top: 3.5rem;
  margin-bottom: 1rem;
  scroll-margin-top: 5rem;
}
.article-body h3 {
  font-family: var(--font-sans, 'Hanken Grotesk', system-ui, sans-serif);
  font-weight: 600;
  font-size: 1.375rem;
  line-height: 1.3;
  color: var(--ink);
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
  scroll-margin-top: 5rem;
}
.article-body h4 {
  font-family: var(--font-sans, 'Hanken Grotesk', system-ui, sans-serif);
  font-weight: 600;
  font-size: 1.125rem;
  color: var(--ink);
  margin-top: 2rem;
  margin-bottom: 0.5rem;
}

.article-body p { margin: 0 0 1.5rem; }
.article-body p:last-child { margin-bottom: 0; }

.article-body a {
  color: var(--purple);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color 0.15s ease;
}
.article-body a:hover {
  color: var(--ink);
  text-decoration-color: var(--ink);
}

.article-body ul, .article-body ol {
  margin: 0 0 1.5rem;
  padding-left: 1.5rem;
}
.article-body li { margin: 0.5rem 0; }
.article-body li > p { margin-bottom: 0.5rem; }

.article-body blockquote {
  margin: 2rem 0;
  padding: 0.25rem 0 0.25rem 1.5rem;
  border-left: 3px solid var(--purple);
  font-family: var(--font-serif, 'Hanken Grotesk', system-ui, sans-serif);
  font-style: normal;
  font-size: 1.25rem;
  line-height: 1.5;
  color: var(--ink);
}
.article-body blockquote p:last-child { margin-bottom: 0; }

.article-body code {
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.9em;
  background: var(--cream-dim);
  padding: 0.125rem 0.375rem;
  border-radius: 4px;
  border: 1px solid var(--border);
}
.article-body pre {
  background: var(--ink);
  color: var(--on-dark);
  padding: 1.25rem 1.5rem;
  border-radius: 10px;
  overflow-x: auto;
  margin: 2rem 0;
  font-size: 0.9375rem;
  line-height: 1.55;
}
.article-body pre code {
  background: transparent;
  border: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  font-size: 1rem;
}
.article-body th, .article-body td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  text-align: left;
  vertical-align: top;
}
.article-body th {
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 500;
  background: var(--cream-dim);
}

.article-body img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 2rem auto;
  border-radius: 8px;
}
.article-body figure { margin: 2rem 0; }
.article-body figcaption {
  font-size: 0.875rem;
  color: var(--muted);
  text-align: center;
  margin-top: 0.75rem;
}

.article-body hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 3rem 0;
}

/* Anchor link icons next to headings (from markdown-it-anchor) */
.article-body .header-anchor {
  color: var(--muted-soft);
  text-decoration: none;
  margin-left: 0.375rem;
  opacity: 0;
  transition: opacity 0.15s ease;
  font-weight: 400;
}
.article-body h2:hover .header-anchor,
.article-body h3:hover .header-anchor,
.article-body h4:hover .header-anchor { opacity: 1; }

/* ---------- Article footer (tags + share) ---------- */
.article-footer {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}
.article-tags, .article-share {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  font-size: 0.875rem;
}
.article-tags-label, .article-share-label {
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin-right: 0.5rem;
}
.article-tags a {
  display: inline-block;
  padding: 0.25rem 0.625rem;
  background: var(--cream-dim);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--ink);
  text-decoration: none;
  font-size: 0.8125rem;
  transition: background 0.15s ease, color 0.15s ease;
}
.article-tags a:hover {
  background: var(--purple-soft);
  color: var(--purple);
}
.article-share a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.article-share a:hover {
  color: var(--purple);
  border-bottom-color: var(--purple);
}

/* ---------- Related articles ---------- */
.related-articles {
  margin-top: 4rem;
  padding-top: 3rem;
  border-top: 1px solid var(--border);
}
.related-articles h2 {
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 1.5rem;
  font-weight: 500;
}
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
}
.related-card {
  display: block;
  text-decoration: none;
  color: var(--ink);
  padding: 1.25rem;
  background: var(--cream-dim);
  border: 1px solid var(--border);
  border-radius: 10px;
  transition: transform 0.15s ease, border-color 0.15s ease;
}
.related-card:hover {
  transform: translateY(-2px);
  border-color: var(--border-strong);
}
.related-card-category {
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.6875rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--purple);
  display: block;
  margin-bottom: 0.5rem;
}
.related-card-title {
  font-family: var(--font-serif, 'Hanken Grotesk', system-ui, sans-serif);
  font-style: normal;
  font-size: 1.25rem;
  line-height: 1.25;
  color: var(--ink);
  margin: 0 0 0.5rem;
}
.related-card-meta {
  font-size: 0.75rem;
  color: var(--muted);
}

/* ---------- Newsletter CTA ---------- */
.newsletter-cta {
  margin-top: 4rem;
  padding: 2.5rem;
  background: var(--cream-dim);
  border: 1px solid var(--border);
  border-radius: 12px;
  text-align: center;
}
.newsletter-cta h2 {
  font-family: var(--font-serif, 'Hanken Grotesk', system-ui, sans-serif);
  font-style: normal;
  font-size: 1.75rem;
  margin: 0 0 0.75rem;
  color: var(--ink);
}
.newsletter-cta p {
  color: var(--muted);
  margin: 0 0 1.5rem;
  font-size: 1rem;
}
.newsletter-form {
  display: flex;
  gap: 0.5rem;
  max-width: 420px;
  margin: 0 auto;
}
.newsletter-form input[type="email"] {
  flex: 1;
  padding: 0.75rem 1rem;
  font-family: inherit;
  font-size: 0.9375rem;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  background: var(--cream);
  color: var(--ink);
  outline: none;
  transition: border-color 0.15s ease;
}
.newsletter-form input[type="email"]:focus { border-color: var(--purple); }
.newsletter-form button {
  padding: 0.75rem 1.25rem;
  font-family: inherit;
  font-size: 0.9375rem;
  font-weight: 500;
  background: var(--ink);
  color: var(--cream);
  border: none;
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.15s ease;
}
.newsletter-form button:hover { background: var(--purple); }

/* ---------- Product CTA ---------- */
.article-product-cta {
  margin-top: 3rem;
  padding: 2.5rem;
  background: var(--ink);
  color: var(--cream);
  border-radius: 12px;
  text-align: center;
}
.article-product-cta h2 {
  font-family: var(--font-serif, 'Hanken Grotesk', system-ui, sans-serif);
  font-style: normal;
  font-size: 1.75rem;
  margin: 0 0 0.75rem;
  color: var(--cream);
}
.article-product-cta p {
  color: var(--on-dark-mute);
  margin: 0 0 1.5rem;
}
.cta-button {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background: var(--cream);
  color: var(--ink);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9375rem;
  border-radius: 999px;
  transition: background 0.15s ease, color 0.15s ease;
}
.cta-button:hover {
  background: var(--purple);
  color: var(--cream);
}

/* ============================================================
   Blog index + category page
   ============================================================ */
.blog-index {
  max-width: 1120px;
  margin: 0 auto;
  padding: 4rem 1.5rem 6rem;
}
.blog-index-hero {
  text-align: center;
  margin-bottom: 4rem;
}
.blog-index-eyebrow {
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 1rem;
}
.blog-index-title {
  font-family: var(--font-serif, 'Hanken Grotesk', system-ui, sans-serif);
  font-style: normal;
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  line-height: 1.05;
  margin: 0 0 1.25rem;
  color: var(--ink);
}
.blog-index-lead {
  font-size: 1.125rem;
  line-height: 1.6;
  color: var(--muted);
  max-width: 56ch;
  margin: 0 auto;
}

.category-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: center;
  margin-bottom: 3rem;
}
.category-filter {
  padding: 0.5rem 1rem;
  background: var(--cream-dim);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--ink);
  text-decoration: none;
  font-size: 0.875rem;
  transition: background 0.15s ease, border-color 0.15s ease;
}
.category-filter:hover {
  background: var(--purple-soft);
  border-color: var(--purple);
}
.category-filter.is-active {
  background: var(--ink);
  color: var(--cream);
  border-color: var(--ink);
}

.featured-article {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
  margin-bottom: 4rem;
  padding-bottom: 4rem;
  border-bottom: 1px solid var(--border);
}
.featured-article-image {
  border-radius: 12px;
  overflow: hidden;
  background: var(--cream-dim);
}
.featured-article-image img { display: block; width: 100%; height: auto; }
.featured-article-eyebrow {
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--purple);
  margin-bottom: 0.75rem;
}
.featured-article h2 {
  font-family: var(--font-serif, 'Hanken Grotesk', system-ui, sans-serif);
  font-style: normal;
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  line-height: 1.15;
  margin: 0 0 1rem;
}
.featured-article h2 a { color: var(--ink); text-decoration: none; }
.featured-article h2 a:hover { color: var(--purple); }
.featured-article-lead {
  font-size: 1.0625rem;
  line-height: 1.6;
  color: var(--muted);
  margin: 0 0 1.5rem;
}
.featured-article-meta {
  display: flex;
  gap: 1rem;
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2.5rem;
}
.article-card {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: var(--ink);
}
.article-card-image {
  aspect-ratio: 16 / 9;
  border-radius: 10px;
  overflow: hidden;
  background: var(--cream-dim);
  margin-bottom: 1.25rem;
}
.article-card-image img,
.article-card-image svg {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}
.article-card:hover .article-card-image img,
.article-card:hover .article-card-image svg { transform: scale(1.03); }

.article-card-category {
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.6875rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--purple);
  margin-bottom: 0.5rem;
}
.article-card h3 {
  font-family: var(--font-serif, 'Hanken Grotesk', system-ui, sans-serif);
  font-style: normal;
  font-weight: 400;
  font-size: 1.5rem;
  line-height: 1.2;
  margin: 0 0 0.625rem;
  color: var(--ink);
}
.article-card:hover h3 { color: var(--purple); }
.article-card-lead {
  font-size: 0.9375rem;
  line-height: 1.55;
  color: var(--muted);
  margin: 0 0 1rem;
  flex: 1;
}
.article-card-meta {
  display: flex;
  gap: 0.75rem;
  font-family: var(--font-mono, 'IBM Plex Mono', ui-monospace, monospace);
  font-size: 0.6875rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
}

/* ---------- Mobile ---------- */
@media (max-width: 640px) {
  .blog-article {
    padding: 2.5rem 1rem 4rem;
  }
  .article-title { font-size: 1.875rem; line-height: 1.15; }
  .article-lead { font-size: 1.0625rem; }
  .article-body { font-size: 1.0625rem; line-height: 1.65; }
  .article-body h2 { font-size: 1.5rem; margin-top: 2.5rem; }
  .article-body h3 { font-size: 1.25rem; }
  .article-body blockquote { padding-left: 1rem; font-size: 1.0625rem; }
  .article-body pre { font-size: 0.875rem; padding: 1rem; }
  .article-toc { padding: 1.25rem; }
  .newsletter-cta, .article-product-cta { padding: 1.75rem 1.25rem; }
  .newsletter-form { flex-direction: column; }

  .blog-index { padding: 2.5rem 1rem 4rem; }
  .featured-article {
    grid-template-columns: 1fr;
    gap: 1.5rem;
    margin-bottom: 3rem;
    padding-bottom: 3rem;
  }
}