/* ============================================================
   ml.research-engineer.ing — stylesheet
   Monochrome · sharp · IBM Plex · enterprise/academic
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500;600&family=IBM+Plex+Sans:ital,wght@0,300;0,400;0,500;0,600;0,700;1,400&family=IBM+Plex+Serif:ital,wght@0,400;0,600;0,700;1,400&display=swap');

/* ── Variables ─────────────────────────────────────────────── */
:root {
  /* Surfaces */
  --bg:           #f4f4f2;
  --bg-elevated:  #ffffff;
  --bg-surface:   #ececea;
  --bg-surface-2: #e0e0de;

  /* Borders */
  --border:        #c8c8c4;
  --border-subtle: #e4e4e0;
  --border-strong: #404040;

  /* Text */
  --text-primary:   #0a0a0a;
  --text-secondary: #484848;
  --text-tertiary:  #8c8c8c;

  /* Pillar tones — monochrome scale */
  --pillar-I-bg:    #0a0a0a;
  --pillar-I-text:  #ffffff;
  --pillar-I-bar:   #0a0a0a;
  --pillar-I-dim:   #f0f0f0;
  --pillar-I-mid:   #c0c0c0;

  --pillar-II-bg:   #363636;
  --pillar-II-text: #ffffff;
  --pillar-II-bar:  #363636;
  --pillar-II-dim:  #f4f4f4;
  --pillar-II-mid:  #c8c8c8;

  --pillar-III-bg:  #6e6e6e;
  --pillar-III-text:#ffffff;
  --pillar-III-bar: #6e6e6e;
  --pillar-III-dim: #f7f7f7;
  --pillar-III-mid: #d0d0d0;

  /* Backwards-compat aliases (used in prose MDX etc.) */
  --color-foundations:     #0a0a0a;
  --color-foundations-dim: #f0f0f0;
  --color-foundations-mid: #c0c0c0;
  --color-frontiers:       #363636;
  --color-frontiers-dim:   #f4f4f4;
  --color-frontiers-mid:   #c8c8c8;
  --color-systems:         #6e6e6e;
  --color-systems-dim:     #f7f7f7;
  --color-systems-mid:     #d0d0d0;

  /* Typography */
  --font-sans:  'IBM Plex Sans',  -apple-system, 'Helvetica Neue', Arial, sans-serif;
  --font-serif: 'IBM Plex Serif', Georgia, 'Times New Roman', serif;
  --font-mono:  'IBM Plex Mono',  'Courier New', Courier, monospace;

  /* Sharp edges */
  --radius-sm: 0px;
  --radius-md: 0px;
  --radius-lg: 0px;

  --max-content: 920px;

  --shadow-sm: 0 1px 4px rgba(0,0,0,0.07), 0 0 0 1px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 14px rgba(0,0,0,0.10), 0 0 0 1px rgba(0,0,0,0.05);

  --t: 0.13s ease;
}

/* ── Reset ─────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  line-height: 1.65;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--text-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ── Navbar ────────────────────────────────────────────────── */
.navbar {
  background: rgba(244,244,242,0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-inner {
  max-width: var(--max-content);
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  text-decoration: none !important;
  flex-shrink: 0;
}

.nav-brand:hover { opacity: 0.7; text-decoration: none; }

.nav-links { display: flex; align-items: center; gap: 0; }

.nav-link {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 400;
  color: var(--text-tertiary);
  padding: 0.3rem 0.75rem;
  border-left: 1px solid transparent;
  transition: color var(--t), background var(--t);
  text-decoration: none !important;
  white-space: nowrap;
  letter-spacing: 0.01em;
}

.nav-link:hover { color: var(--text-primary); text-decoration: none; }

.nav-link.active {
  color: var(--text-primary);
  font-weight: 600;
  border-left-color: var(--text-primary);
}

/* ── Tab Panels ────────────────────────────────────────────── */
.tab-panel { display: block; }
.tab-panel.hidden { display: none; }

/* ── Main ──────────────────────────────────────────────────── */
main {
  max-width: var(--max-content);
  margin: 0 auto;
  padding: 3rem 1.5rem 6rem;
}

/* ── Page Header ───────────────────────────────────────────── */
.page-header {
  margin-bottom: 2.5rem;
  padding-bottom: 1.25rem;
  border-bottom: 2px solid var(--text-primary);
}

.page-title {
  font-family: var(--font-serif);
  font-size: 1.625rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 0.25rem;
  line-height: 1.2;
}

.page-sub {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-tertiary);
  letter-spacing: 0.04em;
}

/* ── Home Hero ─────────────────────────────────────────────── */
.hero {
  padding: 4rem 0 3.5rem;
  max-width: 680px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 3rem;
}

.hero-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.69rem;
  color: var(--text-tertiary);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 1.25rem;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: 3.25rem;
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.035em;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.hero-description {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.8;
  max-width: 60ch;
  font-weight: 300;
}

/* ── Pillar Grid ───────────────────────────────────────────── */
.pillar-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  margin-bottom: 4rem;
  border: 1px solid var(--border);
  background: var(--border); /* gap "colour" */
}

.pillar-card {
  background: var(--bg-elevated);
  padding: 1.75rem 1.5rem 1.5rem;
  cursor: pointer;
  transition: background var(--t);
  position: relative;
}

.pillar-card:hover { background: var(--bg-surface); }

/* Top accent bar */
.pillar-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
}

.pillar-card-foundations::before { background: var(--pillar-I-bar); }
.pillar-card-frontiers::before   { background: var(--pillar-II-bar); }
.pillar-card-systems::before     { background: var(--pillar-III-bar); }

.pillar-roman {
  font-family: var(--font-mono);
  font-size: 0.69rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  margin-bottom: 1rem;
}

.pillar-card-foundations .pillar-roman { color: var(--pillar-I-bg); }
.pillar-card-frontiers   .pillar-roman { color: var(--pillar-II-bg); }
.pillar-card-systems     .pillar-roman { color: var(--pillar-III-bg); }

.pillar-name {
  font-family: var(--font-serif);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.4;
  margin-bottom: 1.25rem;
  letter-spacing: -0.01em;
}

.pillar-count {
  font-family: var(--font-mono);
  font-size: 0.69rem;
  color: var(--text-tertiary);
  letter-spacing: 0.05em;
}

/* ── Home Recent Section ───────────────────────────────────── */
.home-section { margin-bottom: 1rem; }

.home-section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
}

.home-section-label {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-tertiary);
}

.home-section-link {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
  transition: color var(--t);
}

.home-section-link:hover { color: var(--text-primary); text-decoration: none; }

/* ── Archive List ───────────────────────────────────────────── */
#archive-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  border-top: 1px solid var(--border);
}

.archive-empty {
  text-align: center;
  color: var(--text-tertiary);
  padding: 5rem 0;
  font-size: 0.875rem;
  font-family: var(--font-mono);
  letter-spacing: 0.04em;
}

/* ── Item Cards ────────────────────────────────────────────── */
.item-card {
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  padding: 1rem 1.25rem 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1.5rem;
  cursor: pointer;
  transition: background var(--t);
  position: relative;
}

/* Left accent stripe */
.item-card::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  opacity: 0;
  transition: opacity var(--t);
}

.item-card[data-pillar="foundations"]::before { background: var(--pillar-I-bar); }
.item-card[data-pillar="frontiers"]::before   { background: var(--pillar-II-bar); }
.item-card[data-pillar="systems"]::before     { background: var(--pillar-III-bar); }

.item-card:hover { background: var(--bg-surface); }
.item-card:hover::before { opacity: 1; }

.item-card:focus-visible {
  outline: 2px solid var(--text-primary);
  outline-offset: -2px;
}

.item-card-left { flex: 1; min-width: 0; }

.item-title {
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-primary);
  line-height: 1.38;
  margin-bottom: 0.35rem;
  letter-spacing: -0.005em;
}

.item-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
}

.item-date {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--text-tertiary);
  letter-spacing: 0.04em;
}

/* ── Badges (monochrome) ───────────────────────────────────── */
.badge-pillar {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  font-weight: 600;
  padding: 0.1rem 0.45rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.badge-pillar-foundations { background: var(--pillar-I-bg);   color: var(--pillar-I-text); }
.badge-pillar-frontiers   { background: var(--pillar-II-bg);  color: var(--pillar-II-text); }
.badge-pillar-systems     { background: var(--pillar-III-bg); color: var(--pillar-III-text); }
.badge-pillar-all         { background: var(--bg-surface-2);  color: var(--text-secondary); }

.badge-type {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  font-weight: 400;
  padding: 0.1rem 0.45rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  background: var(--bg);
}

.item-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  margin-top: 0.4rem;
}

.item-tag {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  color: var(--text-tertiary);
  letter-spacing: 0.03em;
}

.item-tag::before { content: '#'; }

.item-card-right {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  padding-top: 0.05rem;
}

.view-link {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-tertiary);
  white-space: nowrap;
  transition: color var(--t);
  user-select: none;
}

.item-card:hover .view-link { color: var(--text-primary); }

/* ── Content Viewer ────────────────────────────────────────── */
#content-viewer.hidden { display: none; }

#back-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 400;
  padding: 0.3rem 0.875rem;
  margin-bottom: 2.5rem;
  transition: all var(--t);
  letter-spacing: 0.02em;
}

#back-btn:hover {
  border-color: var(--text-primary);
  color: var(--text-primary);
  background: var(--bg-surface);
}

/* ── Prose ─────────────────────────────────────────────────── */
.prose { max-width: 72ch; }

.prose h1 {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.18;
  margin-bottom: 0.5rem;
  letter-spacing: -0.025em;
}

.prose h2 {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.45rem;
  border-bottom: 1px solid var(--border);
  letter-spacing: -0.01em;
}

.prose h3 {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: 2rem;
  margin-bottom: 0.6rem;
  color: var(--text-secondary);
}

.prose h4 {
  font-size: 0.875rem;
  font-weight: 600;
  margin-top: 1.25rem;
  margin-bottom: 0.35rem;
  color: var(--text-secondary);
}

.prose p { margin-bottom: 1.1rem; }
.prose ul, .prose ol { margin-bottom: 1rem; padding-left: 1.5rem; }
.prose li { margin-bottom: 0.3rem; }

.prose blockquote {
  border-left: 3px solid var(--text-primary);
  padding-left: 1.25rem;
  color: var(--text-secondary);
  font-style: italic;
  margin: 1.5rem 0;
  font-family: var(--font-serif);
}

.prose hr { border: none; border-top: 1px solid var(--border); margin: 2.5rem 0; }
.prose strong { font-weight: 700; }

.prose code:not(pre code) {
  font-family: var(--font-mono);
  font-size: 0.82em;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  padding: 0.1em 0.35em;
  color: var(--text-primary);
}

.prose pre {
  background: #0d0d0d;
  border: 1px solid #2a2a2a;
  overflow-x: auto;
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.65;
}

.prose pre code {
  background: none !important;
  border: none !important;
  padding: 0 !important;
  color: #e6edf3;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
  margin: 1.5rem 0;
}

.prose th {
  background: var(--text-primary);
  border: 1px solid var(--text-primary);
  padding: 0.55rem 0.875rem;
  text-align: left;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #ffffff;
}

.prose td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.875rem;
}

.prose tr:nth-child(even) td { background: var(--bg-surface); }

/* ── MDX Components ────────────────────────────────────────── */
.c-definition {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--text-primary);
  padding: 1rem 1.25rem;
  margin: 1.75rem 0;
}

.c-definition::before {
  content: "Definition  ·  " attr(data-term);
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-primary);
  margin-bottom: 0.55rem;
}

.c-theorem {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--pillar-II-bg);
  padding: 1rem 1.25rem;
  margin: 1.75rem 0;
  font-style: italic;
  font-family: var(--font-serif);
}

.c-theorem::before {
  content: "Theorem  ·  " attr(data-name);
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.68rem;
  font-style: normal;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--pillar-II-bg);
  margin-bottom: 0.55rem;
}

.c-proof {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: 1rem 1.25rem;
  margin: 1.75rem 0;
}

.c-proof::before {
  content: "Proof";
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-tertiary);
  margin-bottom: 0.55rem;
}

.c-qed {
  display: block;
  text-align: right;
  font-size: 1rem;
  margin-top: 0.5rem;
  color: var(--text-secondary);
}

.c-algorithm {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--pillar-III-bg);
  padding: 1rem 1.25rem;
  margin: 1.75rem 0;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  line-height: 1.7;
}

.c-algorithm::before {
  content: "Algorithm  ·  " attr(data-name);
  display: block;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--pillar-III-bg);
  margin-bottom: 0.6rem;
}

.c-callout {
  padding: 0.9rem 1.1rem;
  margin: 1.5rem 0;
  border: 1px solid var(--border);
  border-left: 3px solid;
  background: var(--bg-surface);
}

.c-callout::before {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.67rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  display: block;
  margin-bottom: 0.4rem;
}

.c-callout-note    { border-left-color: var(--text-primary); }
.c-callout-note::before    { content: "Note";    color: var(--text-primary); }
.c-callout-insight { border-left-color: var(--pillar-II-bg); }
.c-callout-insight::before { content: "Insight"; color: var(--pillar-II-bg); }
.c-callout-warning { border-left-color: #8a6000; }
.c-callout-warning::before { content: "Warning"; color: #8a6000; }
.c-callout-danger  { border-left-color: #8a0020; }
.c-callout-danger::before  { content: "Danger";  color: #8a0020; }

.c-figure { margin: 2rem 0; text-align: center; }
.c-figure img { max-width: 100%; border: 1px solid var(--border); }
.c-figure figcaption { font-family: var(--font-serif); font-size: 0.8rem; font-style: italic; color: var(--text-secondary); margin-top: 0.5rem; }

.c-cite {
  font-family: var(--font-mono);
  font-size: 0.75em;
  color: var(--text-secondary);
  vertical-align: super;
  line-height: 0;
}

/* ── KaTeX ─────────────────────────────────────────────────── */
.katex-display { overflow-x: auto; padding: 0.5rem 0; margin: 1.5rem 0; }
.katex-display > .katex { max-width: 100%; }
.katex { font-size: 1em; }

/* ── Northstar Taxonomy ────────────────────────────────────── */
#northstar-body { max-width: 100%; }

#northstar-body > p,
#northstar-body > blockquote {
  max-width: 68ch;
  margin-bottom: 0.75rem;
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.7;
}

#northstar-body > hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 1.75rem 0;
}

/* Pillar section wrapper */
.northstar-pillar {
  border: 1px solid var(--border);
  margin-bottom: 2rem;
  background: var(--bg-elevated);
}

/* Pillar header (h2) */
.northstar-pillar > h2 {
  margin: 0;
  padding: 1rem 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border-bottom: 1px solid;
}

.northstar-pillar-foundations > h2 {
  background: var(--pillar-I-bg);
  color: var(--pillar-I-text);
  border-color: var(--pillar-I-bg);
}

.northstar-pillar-frontiers > h2 {
  background: var(--pillar-II-bg);
  color: var(--pillar-II-text);
  border-color: var(--pillar-II-bg);
}

.northstar-pillar-systems > h2 {
  background: var(--pillar-III-bg);
  color: var(--pillar-III-text);
  border-color: var(--pillar-III-bg);
}

/* Pillar intro paragraph */
.northstar-pillar-intro {
  padding: 0.875rem 1.5rem;
  border-bottom: 1px solid var(--border-subtle);
  background: var(--bg-surface);
}

.northstar-pillar-intro p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin: 0;
}

.northstar-pillar-intro em {
  font-family: var(--font-serif);
  font-style: italic;
}

/* Sub-section group */
.northstar-group {
  padding: 1rem 1.5rem 0.875rem;
  border-top: 1px solid var(--border-subtle);
}

.northstar-group:first-of-type { border-top: none; }

.northstar-group > h3 {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-tertiary);
  margin: 0 0 0.875rem;
}

/* Topic grid */
.northstar-topics {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1px;
  background: var(--border-subtle);
  border: 1px solid var(--border-subtle);
}

/* Each topic card */
.northstar-topic {
  background: var(--bg-elevated);
  padding: 0.6rem 0.75rem;
  margin: 0;
  font-size: 0.8125rem;
  line-height: 1.5;
  color: var(--text-secondary);
  transition: background var(--t);
}

.northstar-topic:hover { background: var(--bg-surface); }

.northstar-topic strong {
  display: block;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
  line-height: 1.3;
  letter-spacing: -0.005em;
}

/* ── Logs ──────────────────────────────────────────────────── */
#logs-body { max-width: 68ch; }

.log-list {
  display: flex;
  flex-direction: column;
  border-left: 2px solid var(--border);
  padding-left: 1.5rem;
  margin-left: 0.5rem;
}

.log-entry {
  position: relative;
  padding-bottom: 2rem;
}

.log-entry::before {
  content: "";
  position: absolute;
  left: -1.75rem;
  top: 0.5rem;
  width: 6px;
  height: 6px;
  background: var(--bg-surface-2);
  border: 1px solid var(--border-strong);
}

.log-entry:first-child::before {
  background: var(--text-primary);
  border-color: var(--text-primary);
}

.log-entry-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.35rem;
  flex-wrap: wrap;
}

.log-date {
  font-family: var(--font-mono);
  font-size: 0.67rem;
  color: var(--text-tertiary);
  letter-spacing: 0.06em;
}

.log-text {
  font-size: 0.9rem;
  line-height: 1.65;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
}

.log-tags { display: flex; flex-wrap: wrap; gap: 0.3rem; }

.log-tag {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  color: var(--text-tertiary);
  letter-spacing: 0.03em;
}

.log-tag::before { content: '#'; }

/* ── Utility ───────────────────────────────────────────────── */
.hidden { display: none !important; }
.hljs { background: transparent !important; padding: 0 !important; }

/* ── Responsive ────────────────────────────────────────────── */
@media (max-width: 680px) {
  .nav-inner { padding: 0 1rem; }
  main { padding: 2rem 1rem 4rem; }
  .hero-title { font-size: 2.25rem; }
  .pillar-grid { grid-template-columns: 1fr; gap: 1px; }
  .northstar-topics { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); }
  .page-title { font-size: 1.375rem; }
}

@media (max-width: 420px) {
  .nav-link { padding: 0.3rem 0.5rem; font-size: 0.75rem; }
  .nav-brand { font-size: 0.7rem; }
  .item-card { flex-direction: column; gap: 0.5rem; }
  .item-card-right { align-self: flex-end; }
}