:root {
    --bg-deep: #0b0e14;
    --bg-primary: #0f1923;
    --bg-card: #131c2b;
    --bg-card-hover: #172236;
    --bg-code: #0a0f18;
    --bg-inline-code: #1a2535;
    --border-subtle: #1e2d42;
    --border-card: #1a2a3e;
    --border-accent: #00e5a033;

    --cyan: #00e5a0;
    --cyan-dim: #00e5a088;
    --cyan-glow: #00e5a022;
    --orange: #f0923a;
    --orange-dim: #f0923a88;
    --pink: #ff6b9d;
    --pink-dim: #ff6b9d66;
    --purple: #a87bff;
    --purple-dim: #a87bff66;
    --yellow: #ffd866;
    --blue: #66d9ef;
    --green: #a6e22e;
    --red: #f92672;

    --text-primary: #e6edf5;
    --text-secondary: #8899aa;
    --text-dim: #556677;
    --text-code: #c8d6e5;

    --font-display: 'Outfit', sans-serif;
    --font-mono: 'JetBrains Mono', 'Space Mono', monospace;

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
  }

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

  html {
    scroll-behavior: smooth;
    scrollbar-width: thin;
    scrollbar-color: var(--border-subtle) var(--bg-deep);
  }

  body {
    background: var(--bg-deep);
    color: var(--text-primary);
    font-family: var(--font-display);
    font-weight: 400;
    line-height: 1.75;
    font-size: 16.5px;
    -webkit-font-smoothing: antialiased;
  }

  .container {
    max-width: 920px;
    margin: 0 auto;
    padding: 0 32px;
  }

  /* ── Hero ── */
  .hero {
    position: relative;
    padding: 40px 0 60px;
    overflow: hidden;
  }

  .hero::before {
    content: '';
    position: absolute;
    top: -200px;
    left: 50%;
    transform: translateX(-50%);
    width: 800px;
    height: 800px;
    background: radial-gradient(ellipse, var(--cyan-glow) 0%, transparent 60%);
    pointer-events: none;
  }

  .hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: 100px;
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--cyan);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    margin-bottom: 28px;
  }

  .hero-badge::before {
    content: '';
    width: 6px;
    height: 6px;
    background: var(--cyan);
    border-radius: 50%;
    box-shadow: 0 0 8px var(--cyan);
  }

  .hero h1 {
    font-size: clamp(42px, 6vw, 68px);
    font-weight: 900;
    line-height: 1.05;
    letter-spacing: -0.03em;
    margin-bottom: 20px;
  }

  .hero h1 .go { color: var(--orange); }
  .hero h1 .python { color: var(--cyan); }

  .hero-sub {
    font-size: 19px;
    color: var(--text-secondary);
    font-weight: 300;
    max-width: 620px;
    line-height: 1.6;
  }

  .hero-sub strong {
    color: var(--text-primary);
    font-weight: 500;
  }

  /* ── KPI Cards ── */
  .kpi-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 12px;
    margin: 48px 0 64px;
  }

  .kpi-card {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    padding: 20px 16px;
    text-align: center;
  }

  .kpi-label {
    font-size: 11px;
    font-family: var(--font-mono);
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 6px;
  }

  .kpi-value {
    font-size: 32px;
    font-weight: 800;
    line-height: 1.1;
  }

  .kpi-value.cyan { color: var(--cyan); }
  .kpi-value.orange { color: var(--orange); }
  .kpi-value.pink { color: var(--pink); }
  .kpi-value.purple { color: var(--purple); }

  .kpi-sub {
    font-size: 11px;
    color: var(--text-dim);
    margin-top: 4px;
  }

  /* ── TOC ── */
  .toc {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-lg);
    padding: 36px 40px;
    margin-bottom: 72px;
  }

  .toc-title {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--cyan);
    text-transform: uppercase;
    letter-spacing: 0.15em;
    margin-bottom: 20px;
  }

  .toc-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 6px 40px;
  }

  .toc a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14.5px;
    font-weight: 400;
    padding: 5px 0;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: color 0.2s;
  }

  .toc a:hover { color: var(--cyan); }

  .toc a .num {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-dim);
    min-width: 24px;
  }

  /* ── Sections ── */
  .section {
    margin-bottom: 80px;
    animation: fadeIn 0.4s ease-out;
  }

  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
  }

  .section-num {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--cyan-dim);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    margin-bottom: 8px;
  }

  h2 {
    font-size: 32px;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 24px;
    line-height: 1.2;
  }

  h3 {
    font-size: 20px;
    font-weight: 700;
    margin: 40px 0 16px;
    color: var(--text-primary);
    letter-spacing: -0.01em;
  }

  h4 {
    font-size: 15px;
    font-weight: 600;
    color: var(--orange);
    font-family: var(--font-mono);
    margin: 28px 0 12px;
    letter-spacing: 0.02em;
  }

  p {
    margin-bottom: 16px;
    color: var(--text-secondary);
    line-height: 1.8;
  }

  p strong {
    color: var(--text-primary);
    font-weight: 600;
  }

  /* ── Code Blocks ── */
  pre {
    background: var(--bg-code);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: 24px 28px;
    margin: 16px 0 24px;
    overflow-x: auto;
    position: relative;
  }

  pre::before {
    content: attr(data-lang);
    position: absolute;
    top: 10px;
    right: 14px;
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 0.1em;
  }

  pre code {
    font-family: var(--font-mono);
    font-size: 13.5px;
    line-height: 1.7;
    color: var(--text-code);
  }

  code {
    font-family: var(--font-mono);
    font-size: 0.88em;
  }

  p code, li code, td code {
    background: var(--bg-inline-code);
    padding: 2px 7px;
    border-radius: 4px;
    color: var(--cyan);
    font-size: 0.85em;
    border: 1px solid var(--border-subtle);
  }

  /* Syntax colors */
  .kw { color: var(--red); font-weight: 500; }
  .fn { color: var(--cyan); }
  .ty { color: var(--blue); font-style: italic; }
  .st { color: var(--yellow); }
  .cm { color: var(--text-dim); font-style: italic; }
  .num { color: var(--purple); }
  .mac { color: var(--orange); }
  .lt { color: var(--purple); }
  .attr { color: var(--green); }
  .pkg { color: var(--pink); }

  /* ── Comparison Panels ── */
  .compare {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin: 16px 0 24px;
  }

  .compare-panel {
    background: var(--bg-code);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    overflow: hidden;
  }

  .compare-panel.python { border-top: 2px solid var(--cyan); }
  .compare-panel.go { border-top: 2px solid var(--orange); }

  .compare-header {
    padding: 10px 16px;
    font-family: var(--font-mono);
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    border-bottom: 1px solid var(--border-subtle);
  }

  .compare-panel.python .compare-header { color: var(--cyan); }
  .compare-panel.go .compare-header { color: var(--orange); }

  .compare-panel pre {
    margin: 0;
    border: none;
    border-radius: 0;
    padding: 16px 20px;
  }

  /* ── Callout Boxes ── */
  .callout {
    border-radius: var(--radius-md);
    padding: 20px 24px;
    margin: 24px 0;
    border-left: 3px solid;
  }

  .callout-key {
    background: var(--cyan-glow);
    border-color: var(--cyan);
  }

  .callout-warn {
    background: #ff6b9d11;
    border-color: var(--pink);
  }

  .callout-insight {
    background: #a87bff11;
    border-color: var(--purple);
  }

  .callout-title {
    font-family: var(--font-mono);
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    margin-bottom: 8px;
    font-weight: 600;
  }

  .callout-key .callout-title { color: var(--cyan); }
  .callout-warn .callout-title { color: var(--pink); }
  .callout-insight .callout-title { color: var(--purple); }

  .callout p {
    margin-bottom: 0;
    font-size: 14.5px;
    line-height: 1.7;
  }

  /* ── Tables ── */
  .table-wrap {
    margin: 20px 0 28px;
    overflow-x: auto;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-card);
  }

  table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
  }

  thead {
    background: var(--bg-card);
  }

  th {
    padding: 12px 20px;
    text-align: left;
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--cyan);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 600;
    border-bottom: 1px solid var(--border-card);
  }

  td {
    padding: 11px 20px;
    border-bottom: 1px solid var(--border-subtle);
    color: var(--text-secondary);
  }

  tr:last-child td { border-bottom: none; }

  tr:hover td {
    background: var(--bg-card);
  }

  /* ── Divider ── */
  .divider {
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--border-subtle), transparent);
    margin: 72px 0;
  }

  /* ── Diagram Boxes ── */
  .diagram {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-lg);
    padding: 32px;
    margin: 24px 0;
    font-family: var(--font-mono);
    font-size: 13px;
    line-height: 1.6;
    overflow-x: auto;
    white-space: pre-wrap;
  }

  .diagram .label { color: var(--text-dim); }
  .diagram .val { color: var(--cyan); }
  .diagram .moved { color: var(--pink); text-decoration: line-through; }
  .diagram .arrow { color: var(--orange); }
  .diagram .ok { color: var(--green); }
  .diagram .err { color: var(--red); }

  /* ── Flow boxes ── */
  .flow-row {
    display: flex;
    gap: 12px;
    align-items: center;
    margin: 20px 0;
    flex-wrap: wrap;
  }

  .flow-box {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    padding: 14px 20px;
    text-align: center;
    flex: 1;
    min-width: 120px;
  }

  .flow-box.active {
    border-color: var(--cyan);
    box-shadow: 0 0 20px var(--cyan-glow);
  }

  .flow-box .flow-label {
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 4px;
  }

  .flow-box .flow-value {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-primary);
  }

  .flow-arrow {
    color: var(--orange);
    font-size: 20px;
    flex-shrink: 0;
  }

  /* ── Footer ── */
  .footer {
    border-top: 1px solid var(--border-subtle);
    padding: 48px 0;
    margin-top: 80px;
    text-align: center;
  }

  .footer p {
    font-size: 13px;
    color: var(--text-dim);
  }

  .footer a {
    color: var(--cyan);
    text-decoration: none;
  }

  /* ── Lists ── */
  ul, ol {
    margin: 12px 0 20px 0;
    padding-left: 0;
    list-style: none;
  }

  li {
    color: var(--text-secondary);
    padding: 4px 0 4px 20px;
    position: relative;
    font-size: 15.5px;
  }

  li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--cyan-dim);
    font-size: 12px;
    top: 7px;
  }

  ol { counter-reset: ol-counter; }
  ol li { counter-increment: ol-counter; }
  ol li::before {
    content: counter(ol-counter) '.';
    color: var(--orange-dim);
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 600;
    top: 6px;
  }

  /* ── Responsive ── */
  @media (max-width: 700px) {
    .container { padding: 0 20px; }
    .hero { padding: 20px 0 32px; }
    .hero h1 { font-size: 36px; }
    .kpi-row { grid-template-columns: repeat(2, 1fr); }
    .compare { grid-template-columns: 1fr; }
    .toc-grid { grid-template-columns: 1fr; }
    h2 { font-size: 26px; }
  }

/* ── Navbar ── */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(11, 14, 20, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
}

.navbar-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.navbar-brand {
  text-decoration: none;
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-right: 24px;
  flex-shrink: 0;
}

.brand-go { color: var(--orange); }
.brand-sep { color: var(--text-dim); margin: 0 1px; }
.brand-py { color: var(--cyan); }

.navbar-links {
  display: flex;
  align-items: center;
  gap: 2px;
  overflow-x: auto;
  scrollbar-width: none;
}

.navbar-links::-webkit-scrollbar { display: none; }

.nav-link {
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-secondary);
  padding: 6px 12px;
  border-radius: 6px;
  white-space: nowrap;
  transition: color 0.15s, background 0.15s;
  letter-spacing: 0.01em;
}

.nav-link:hover {
  color: var(--text-primary);
  background: var(--bg-card);
}

.nav-link.active {
  color: var(--cyan);
  background: var(--cyan-glow);
}

.navbar-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  margin-left: auto;
}

.navbar-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text-secondary);
  border-radius: 1px;
  transition: transform 0.2s;
}

/* Content offset for fixed navbar */
.content-area {
  padding-top: 80px;
}

/* ── Mobile nav ── */
@media (max-width: 700px) {
  .navbar-links {
    display: none;
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-subtle);
    flex-direction: column;
    padding: 12px 16px;
    gap: 2px;
  }

  .navbar-links.open {
    display: flex;
  }

  .nav-link {
    padding: 10px 14px;
    font-size: 13.5px;
  }

  .navbar-toggle {
    display: flex;
  }
}

/* ── HTMX loading indicator ── */
.htmx-request #content {
  opacity: 0.5;
  transition: opacity 0.15s;
}