:root {
    --paper:        #f4f1ea;
    --paper-2:      #ece8de;
    --rule:         #d9d4c5;
    --rule-2:       #c4bfae;
    --ink:          #1a1a17;
    --ink-2:        #4a4842;
    --ink-3:        #837f72;
    --clay:         oklch(58% 0.13 40);
    --clay-soft:    oklch(58% 0.13 40 / 0.10);
    --clay-rule:    oklch(58% 0.13 40 / 0.35);

    --maxw: 1240px;
    --gutter: clamp(20px, 4vw, 56px);
    --serif: "Instrument Serif", "Times New Roman", serif;
    --sans:  "Geist", ui-sans-serif, system-ui, sans-serif;
    --mono:  "Geist Mono", ui-monospace, "SF Mono", Menlo, monospace;
  }

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

  body {
    background: var(--paper);
    color: var(--ink);
    font-family: var(--sans);
    font-size: 16px;
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
    /* Faint paper texture via two layered gradients — keeps weight and warmth */
    background-image:
      radial-gradient(1200px 700px at 80% -10%, oklch(58% 0.13 40 / 0.06), transparent 60%),
      radial-gradient(900px 600px at -10% 110%, oklch(58% 0.13 40 / 0.04), transparent 70%);
    background-attachment: fixed;
  }

  ::selection { background: var(--clay); color: var(--paper); }

  a { color: inherit; text-decoration: none; }

  /* ─── Layout ────────────────────────────────────────────────────────── */
  .wrap {
    max-width: var(--maxw);
    margin: 0 auto;
    padding-left: var(--gutter);
    padding-right: var(--gutter);
  }

  .rule {
    border: 0;
    border-top: 1px solid var(--rule);
    margin: 0;
  }

  /* ─── Mono section markers ─────────────────────────────────────────── */
  .marker {
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--ink-3);
    display: inline-flex;
    align-items: center;
    gap: 10px;
  }
  .marker .dot { width: 5px; height: 5px; border-radius: 50%; background: var(--clay); }

  /* ─── Top bar ──────────────────────────────────────────────────────── */
  .topbar {
    position: sticky;
    top: 0;
    z-index: 50;
    backdrop-filter: blur(8px);
    background: color-mix(in srgb, var(--paper) 88%, transparent);
    border-bottom: 1px solid var(--rule);
  }
  .topbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
  }
  .brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-family: var(--mono);
    font-size: 13px;
    letter-spacing: 0.02em;
  }
  .brand-mark {
    width: 33px !important; 
    height: 33px !important;
    display: block;
  }
  .brand b { font-weight: 600; color: var(--ink); }
  .brand span { color: var(--ink-3); }

  .topnav {
    display: flex;
    align-items: center;
    gap: 28px;
    font-family: var(--mono);
    font-size: 12.5px;
    color: var(--ink-2);
  }
  .topnav a:hover { color: var(--clay); }
  .topnav .pill {
    border: 1px solid var(--ink);
    border-radius: 999px;
    padding: 6px 12px;
    color: var(--ink);
    font-family: var(--mono);
    font-size: 12px;
    transition: background .2s ease, color .2s ease;
  }
  .topnav .pill:hover { background: var(--ink); color: var(--paper); }

  @media (max-width: 720px) {
    .topnav .hide-sm { display: none; }
  }

  /* ─── Hero ─────────────────────────────────────────────────────────── */
  .hero {
    padding: clamp(56px, 9vw, 120px) 0 clamp(64px, 9vw, 110px);
    position: relative;
  }
  .hero-grid {
    display: grid;
    grid-template-columns: 1.05fr 1fr;
    gap: clamp(32px, 5vw, 80px);
    align-items: center;
  }
  @media (max-width: 920px) {
    .hero-grid { grid-template-columns: 1fr; gap: 56px; }
  }

  .eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    font-family: var(--mono);
    font-size: 11.5px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--ink-2);
    margin-bottom: 28px;
  }
  .eyebrow .v {
    color: var(--clay);
    border: 1px solid var(--clay-rule);
    border-radius: 999px;
    padding: 3px 9px;
    background: var(--clay-soft);
  }

  h1.headline {
    font-family: var(--serif);
    font-weight: 400;
    font-size: clamp(54px, 8vw, 108px);
    line-height: 0.96;
    letter-spacing: -0.015em;
    margin: 0 0 28px;
    color: var(--ink);
  }
  h1.headline em {
    font-style: italic;
    color: var(--clay);
  }
  h1.headline .small {
    display: block;
    font-style: italic;
    font-size: 0.42em;
    line-height: 1.2;
    letter-spacing: 0;
    color: var(--ink-2);
    margin-top: 14px;
    font-family: var(--serif);
  }

  .lede {
    font-size: 17.5px;
    line-height: 1.6;
    color: var(--ink-2);
    max-width: 46ch;
    margin: 0 0 36px;
  }

  .actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    align-items: center;
  }
  .btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 13px 18px;
    font-family: var(--mono);
    font-size: 13px;
    letter-spacing: 0.01em;
    border-radius: 8px;
    transition: transform .15s ease, background .2s ease, color .2s ease, border-color .2s ease;
  }
  .btn-primary {
    background: var(--ink);
    color: var(--paper);
    border: 1px solid var(--ink);
  }
  .btn-primary:hover { background: var(--clay); border-color: var(--clay); }
  .btn-ghost {
    background: transparent;
    color: var(--ink);
    border: 1px solid var(--rule-2);
  }
  .btn-ghost:hover { border-color: var(--ink); }
  .btn .arrow { transition: transform .2s ease; }
  .btn:hover .arrow { transform: translateX(3px); }

  .meta-row {
    margin-top: 36px;
    display: flex;
    gap: 28px;
    flex-wrap: wrap;
    font-family: var(--mono);
    font-size: 12px;
    color: var(--ink-3);
  }
  .meta-row b { color: var(--ink); font-weight: 500; }

  /* ─── Hero diagram ─────────────────────────────────────────────────── */
  .diagram-card {
    position: relative;
    aspect-ratio: 1 / 1;
    background:
      linear-gradient(180deg, var(--paper-2), var(--paper));
    border: 1px solid var(--rule);
    border-radius: 4px;
    overflow: hidden;
  }
  .diagram-card::before {
    /* plotter-paper grid */
    content: "";
    position: absolute; inset: 0;
    background-image:
      linear-gradient(to right, var(--rule) 1px, transparent 1px),
      linear-gradient(to bottom, var(--rule) 1px, transparent 1px);
    background-size: 40px 40px;
    opacity: 0.45;
    mask-image: radial-gradient(circle at 50% 50%, black 50%, transparent 90%);
  }
  .diagram-card .corner {
    position: absolute;
    font-family: var(--mono);
    font-size: 10.5px;
    color: var(--ink-3);
    letter-spacing: 0.04em;
  }
  .diagram-card .tl { top: 14px; left: 16px; }
  .diagram-card .tr { top: 14px; right: 16px; }
  .diagram-card .bl { bottom: 14px; left: 16px; }
  .diagram-card .br { bottom: 14px; right: 16px; }

  .diagram-card svg {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    display: block;
  }

  /* ─── Section frame ────────────────────────────────────────────────── */
  section.block {
    padding: clamp(64px, 8vw, 120px) 0;
    border-top: 1px solid var(--rule);
  }
  .block-head {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: clamp(24px, 4vw, 60px);
    margin-bottom: 56px;
  }
  @media (max-width: 760px) {
    .block-head { grid-template-columns: 1fr; gap: 16px; margin-bottom: 36px; }
  }
  .block-head .label { padding-top: 8px; }
  .block-head h2 {
    font-family: var(--serif);
    font-weight: 400;
    font-size: clamp(34px, 4.4vw, 56px);
    line-height: 1.04;
    letter-spacing: -0.012em;
    margin: 0;
    max-width: 22ch;
  }
  .block-head h2 em { font-style: italic; color: var(--clay); }

  /* ─── Pillars (3-up) ───────────────────────────────────────────────── */
  .pillars {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0;
    border-top: 1px solid var(--rule);
    border-bottom: 1px solid var(--rule);
  }
  .pillar {
    padding: 36px 32px 40px;
    border-right: 1px solid var(--rule);
    background: linear-gradient(180deg, transparent, transparent);
    transition: background .25s ease;
  }
  .pillar:last-child { border-right: none; }
  .pillar:hover { background: oklch(58% 0.13 40 / 0.04); }
  .pillar .num {
    font-family: var(--mono);
    font-size: 11px;
    color: var(--ink-3);
    letter-spacing: 0.08em;
    margin-bottom: 32px;
    display: flex;
    justify-content: space-between;
  }
  .pillar h3 {
    font-family: var(--serif);
    font-style: italic;
    font-weight: 400;
    font-size: 30px;
    line-height: 1.1;
    margin: 0 0 14px;
    letter-spacing: -0.01em;
  }
  .pillar p {
    margin: 0;
    color: var(--ink-2);
    font-size: 15px;
    line-height: 1.6;
  }
  .pillar .glyph {
    width: 44px;
    height: 44px;
    margin-bottom: 28px;
    color: var(--ink);
  }
  @media (max-width: 820px) {
    .pillars { grid-template-columns: 1fr; }
    .pillar { border-right: none; border-bottom: 1px solid var(--rule); }
    .pillar:last-child { border-bottom: none; }
  }

  /* ─── Anatomy ──────────────────────────────────────────────────────── */
  .anatomy {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: clamp(32px, 5vw, 72px);
    align-items: start;
  }
  @media (max-width: 920px) { .anatomy { grid-template-columns: 1fr; } }

  .ana-list {
    list-style: none;
    margin: 0;
    padding: 0;
  }
  .ana-list li {
    display: grid;
    grid-template-columns: 60px 1fr;
    gap: 18px;
    padding: 22px 0;
    border-top: 1px solid var(--rule);
  }
  .ana-list li:last-child { border-bottom: 1px solid var(--rule); }
  .ana-list .k {
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.08em;
    color: var(--ink-3);
    padding-top: 4px;
  }
  .ana-list h4 {
    font-family: var(--serif);
    font-style: italic;
    font-weight: 400;
    font-size: 22px;
    line-height: 1.2;
    margin: 0 0 6px;
  }
  .ana-list p {
    margin: 0;
    color: var(--ink-2);
    font-size: 14.5px;
    line-height: 1.55;
  }

  .ana-art {
    position: sticky;
    top: 90px;
    aspect-ratio: 4 / 5;
    background: var(--paper-2);
    border: 1px solid var(--rule);
    border-radius: 4px;
    overflow: hidden;
    padding: 36px;
  }
  .ana-art .legend {
    position: absolute;
    bottom: 18px;
    left: 18px;
    right: 18px;
    display: flex;
    justify-content: space-between;
    font-family: var(--mono);
    font-size: 10.5px;
    color: var(--ink-3);
    letter-spacing: 0.04em;
  }

  /* ─── Spec table ───────────────────────────────────────────────────── */
  .spec {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0;
    border: 1px solid var(--rule);
    border-radius: 4px;
    overflow: hidden;
    background: color-mix(in srgb, var(--paper-2) 50%, var(--paper));
  }
  .spec .row {
    padding: 22px 28px;
    border-bottom: 1px solid var(--rule);
    border-right: 1px solid var(--rule);
    display: grid;
    grid-template-columns: 130px 1fr;
    gap: 16px;
    align-items: baseline;
  }
  .spec .row:nth-child(2n) { border-right: none; }
  .spec .row:nth-last-child(-n+2) { border-bottom: none; }
  .spec .key {
    font-family: var(--mono);
    font-size: 11.5px;
    color: var(--ink-3);
    letter-spacing: 0.04em;
    text-transform: uppercase;
  }
  .spec .val {
    font-family: var(--serif);
    font-style: italic;
    font-size: 21px;
    line-height: 1.3;
    color: var(--ink);
  }
  .spec .val small {
    display: block;
    font-family: var(--sans);
    font-style: normal;
    font-size: 13.5px;
    color: var(--ink-2);
    margin-top: 4px;
    line-height: 1.5;
  }
  @media (max-width: 760px) {
    .spec { grid-template-columns: 1fr; }
    .spec .row { border-right: none; }
    .spec .row:nth-last-child(2) { border-bottom: 1px solid var(--rule); }
  }

  /* ─── Compare ──────────────────────────────────────────────────────── */
  .compare {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: clamp(20px, 3vw, 36px);
  }
  .compare-card {
    padding: 36px 36px 40px;
    background: var(--paper);
    border: 1px solid var(--rule);
    border-radius: 4px;
    position: relative;
  }
  .compare-card .tag {
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.08em;
    color: var(--ink-3);
    text-transform: uppercase;
    margin-bottom: 14px;
  }
  .compare-card h3 {
    font-family: var(--serif);
    font-weight: 400;
    font-size: 30px;
    line-height: 1.1;
    margin: 0 0 18px;
    letter-spacing: -0.01em;
  }
  .compare-card h3 em { font-style: italic; color: var(--clay); }
  .compare-card p {
    color: var(--ink-2);
    font-size: 15px;
    line-height: 1.65;
    margin: 0 0 14px;
  }
  .compare-card .quote {
    margin-top: 22px;
    padding-top: 22px;
    border-top: 1px solid var(--rule);
    font-family: var(--serif);
    font-style: italic;
    font-size: 18px;
    line-height: 1.4;
    color: var(--ink);
  }
  @media (max-width: 820px) { .compare { grid-template-columns: 1fr; } }

  /* ─── Code / get started ───────────────────────────────────────────── */
  .start {
    display: grid;
    grid-template-columns: 1fr 1.1fr;
    gap: clamp(28px, 4vw, 64px);
    align-items: center;
  }
  @media (max-width: 920px) { .start { grid-template-columns: 1fr; } }

  .start h2 {
    font-family: var(--serif);
    font-weight: 400;
    font-size: clamp(36px, 5vw, 60px);
    line-height: 1.04;
    margin: 0 0 18px;
    letter-spacing: -0.012em;
  }
  .start h2 em { font-style: italic; color: var(--clay); }
  .start p {
    color: var(--ink-2);
    font-size: 16px;
    margin: 0 0 24px;
    max-width: 46ch;
  }

  .terminal {
    border: 1px solid var(--rule);
    border-radius: 6px;
    overflow: hidden;
    background: var(--paper);
    box-shadow:
      0 1px 0 0 oklch(58% 0.13 40 / 0.04),
      0 30px 60px -40px rgba(26, 26, 23, 0.18);
  }
  .term-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 14px;
    background: var(--paper-2);
    border-bottom: 1px solid var(--rule);
    font-family: var(--mono);
    font-size: 11px;
    color: var(--ink-3);
  }
  .term-dots { display: flex; gap: 6px; }
  .term-dots span {
    width: 9px; height: 9px; border-radius: 50%;
    background: var(--rule-2);
  }
  .term-body {
    font-family: var(--mono);
    font-size: 13px;
    line-height: 1.7;
    padding: 22px 22px 26px;
    color: var(--ink);
    overflow-x: auto;
  }
  .term-body .c { color: var(--ink-3); }
  .term-body .a { color: var(--clay); }
  .term-body .p { color: var(--ink-3); user-select: none; margin-right: 10px; }
  .term-body .k { color: var(--ink); font-weight: 500; }
  .term-cursor {
    display: inline-block;
    width: 7px; height: 14px;
    background: var(--clay);
    transform: translateY(2px);
    margin-left: 4px;
    animation: blink 1.05s steps(2) infinite;
  }
  @keyframes blink { 50% { opacity: 0; } }

  /* ─── Footer ───────────────────────────────────────────────────────── */
  footer.foot {
    border-top: 1px solid var(--rule);
    padding: 56px 0 64px;
    margin-top: 0;
  }
  .foot-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 32px;
  }
  @media (max-width: 760px) { .foot-grid { grid-template-columns: 1fr 1fr; } }

  .foot-grid h5 {
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--ink-3);
    margin: 0 0 14px;
    font-weight: 500;
  }
  .foot-grid ul {
    list-style: none;
    margin: 0;
    padding: 0;
  }
  .foot-grid li { margin-bottom: 8px; }
  .foot-grid a { color: var(--ink-2); font-size: 14px; }
  .foot-grid a:hover { color: var(--clay); }

  .foot-mark {
    font-family: var(--serif);
    font-size: 38px;
    line-height: 1.05;
    letter-spacing: -0.01em;
  }
  .foot-mark em { font-style: italic; color: var(--clay); }

  .foot-meta {
    margin-top: 56px;
    padding-top: 22px;
    border-top: 1px solid var(--rule);
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    font-family: var(--mono);
    font-size: 11.5px;
    color: var(--ink-3);
  }

  /* ─── Animation primitives ─────────────────────────────────────────── */
  .flow-path {
    fill: none;
    stroke: var(--ink);
    stroke-width: 1;
    opacity: 0.55;
  }
  .flow-path.thin { stroke-width: 0.6; opacity: 0.35; }
  .flow-path.accent { stroke: var(--clay); opacity: 0.9; stroke-width: 1.2; }

  .pulse {
    fill: var(--clay);
    r: 3.5;
    filter: drop-shadow(0 0 4px oklch(58% 0.13 40 / 0.5));
  }

  .node-c {
    fill: var(--paper);
    stroke: var(--ink);
    stroke-width: 1.2;
  }
  .node-c.accent { stroke: var(--clay); stroke-width: 1.6; }
  .node-fill { fill: var(--ink); }
  .node-fill.accent { fill: var(--clay); }
  .node-label {
    font-family: var(--mono);
    font-size: 9.5px;
    fill: var(--ink-3);
    letter-spacing: 0.04em;
  }

  /* fade-in on scroll */
  .reveal { opacity: 0; transform: translateY(14px); transition: opacity .8s ease, transform .8s ease; }
  .reveal.in { opacity: 1; transform: none; }