:root {
  --paper: #ffffff;
  --ink: #000000;
  --ink-70: rgba(0, 0, 0, 0.68);
  --ink-50: rgba(0, 0, 0, 0.5);
  --ink-35: rgba(0, 0, 0, 0.34);
  --ink-18: rgba(0, 0, 0, 0.18);
  --ink-08: rgba(0, 0, 0, 0.07);
  --ink-04: rgba(0, 0, 0, 0.035);

  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, "Cascadia Mono", Menlo, monospace;

  --measure: 64ch;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

[data-theme="dark"] {
  --paper: #000000;
  --ink: #ffffff;
  --ink-70: rgba(255, 255, 255, 0.7);
  --ink-50: rgba(255, 255, 255, 0.52);
  --ink-35: rgba(255, 255, 255, 0.36);
  --ink-18: rgba(255, 255, 255, 0.2);
  --ink-08: rgba(255, 255, 255, 0.09);
  --ink-04: rgba(255, 255, 255, 0.05);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-size: 14px;
  line-height: 1.68;
  font-feature-settings: "cv11", "ss01";
  -webkit-font-smoothing: antialiased;
  transition: background 0.35s var(--ease), color 0.35s var(--ease);
}

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

/* ---------- links: underlined, always ---------- */
a {
  color: inherit;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: background 0.15s, color 0.15s;
}
a:hover { background: var(--ink); color: var(--paper); text-decoration-color: transparent; }
a:focus-visible { outline: 1px solid var(--ink); outline-offset: 2px; }

#progress {
  position: fixed;
  top: 0; left: 0;
  height: 2px;
  width: 0%;
  background: var(--ink);
  z-index: 100;
}

/* ---------- the opening menu ---------- */
.screen { display: none; }
.screen.is-open { display: block; }

#screen-menu.is-open {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 40px 24px;
}

.menu { text-align: center; }
.menu ul { list-style: none; margin: 0; padding: 0; }
.menu li { margin: 14px 0; }
.menu a {
  font-family: var(--mono);
  font-size: 17px;
  letter-spacing: 0.01em;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
  padding: 2px 4px;
  position: relative;
  display: inline-block;
}
.menu a::before {
  content: "→";
  position: absolute;
  left: -22px;
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity 0.2s var(--ease), transform 0.2s var(--ease);
}
.menu a:hover::before { opacity: 1; transform: none; }
.menu a.is-empty { color: var(--ink-35); }

.menu .caret {
  display: inline-block;
  width: 7px;
  height: 14px;
  background: var(--ink);
  margin-left: 2px;
  vertical-align: -2px;
  animation: blink 1.1s steps(1) infinite;
}
@keyframes blink { 50% { opacity: 0; } }

.menu-foot {
  margin-top: 42px;
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--ink-35);
  letter-spacing: 0.06em;
}
.menu-foot a { text-decoration-color: var(--ink-18); }

/* ---------- inner pages ---------- */
.wrap {
  max-width: 720px;
  margin: 0 auto;
  padding: 30px 24px 120px;
}

.back {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  display: inline-block;
  margin-bottom: 42px;
  text-decoration-color: var(--ink-18);
}

.page-title {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-50);
  margin: 0 0 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--ink-18);
}

.label {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-50);
}

/* ---------- article list ---------- */
.entries { margin-top: 4px; }
.entry {
  display: block;
  text-decoration: none;
  padding: 16px 0;
  border-bottom: 1px dotted var(--ink-18);
}
.entry:hover { background: transparent; color: inherit; }
.entry .row { display: flex; gap: 10px; align-items: baseline; }
.entry .idx { font-family: var(--mono); font-size: 11px; color: var(--ink-35); flex: none; }
.entry .name {
  font-size: 15px;
  font-weight: 550;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
.entry:hover .name { background: var(--ink); color: var(--paper); text-decoration-color: transparent; }
.entry .dek { margin: 5px 0 0 26px; font-size: 12.5px; color: var(--ink-70); max-width: 62ch; }
.entry .meta { margin: 7px 0 0 26px; font-family: var(--mono); font-size: 10px; color: var(--ink-35); letter-spacing: 0.06em; }
.empty { font-family: var(--mono); font-size: 11.5px; color: var(--ink-35); padding: 20px 0; }

/* ---------- about: everything small ---------- */
.small { font-size: 12.5px; line-height: 1.75; }
.small p { margin: 12px 0 0; max-width: 66ch; }
.small ol, .small ul { margin: 12px 0 0; padding-left: 20px; max-width: 66ch; }
.small li { margin: 5px 0; }
.small li::marker { color: var(--ink-35); }
.small strong { font-weight: 600; }

/* ---------- article body ---------- */
.article-head { margin-bottom: 8px; }
.article-head .kicker {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-50);
  margin-bottom: 14px;
}
.article-head h1 {
  font-size: 26px;
  line-height: 1.16;
  letter-spacing: -0.02em;
  font-weight: 600;
  margin: 0;
  max-width: 26ch;
}
.article-head .dek {
  font-size: 14px;
  color: var(--ink-70);
  max-width: 60ch;
  margin: 14px 0 0;
}

.prose { max-width: var(--measure); }
.prose p { margin: 14px 0 0; }
.prose h2 {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin: 56px 0 4px;
  padding-top: 10px;
  border-top: 1px solid var(--ink-18);
  display: flex;
  gap: 10px;
}
.prose h2 .num { color: var(--ink-35); }
.prose h3 { font-size: 15px; font-weight: 600; margin: 26px 0 0; letter-spacing: -0.01em; }
.prose ul, .prose ol { margin: 14px 0 0; padding-left: 20px; }
.prose li { margin: 5px 0; }
.prose li::marker { color: var(--ink-35); }
.prose strong { font-weight: 600; }
.prose em { font-style: italic; }
.prose hr {
  border: 0;
  border-top: 1px dotted var(--ink-18);
  margin: 40px 0;
}

.prose code {
  font-family: var(--mono);
  font-size: 0.87em;
  background: var(--ink-04);
  border: 1px solid var(--ink-08);
  padding: 0 3px;
}
.prose pre {
  font-family: var(--mono);
  font-size: 11.5px;
  line-height: 1.75;
  border: 1px solid var(--ink-18);
  padding: 12px 14px;
  overflow-x: auto;
  margin: 18px 0 0;
  background: var(--ink-04);
}
.prose pre code { background: none; border: 0; padding: 0; }

blockquote {
  margin: 22px 0 0;
  padding: 0 0 0 14px;
  border-left: 2px solid var(--ink);
  font-size: 13.5px;
}
blockquote p:first-child { margin-top: 0; }

/* the aside boxes */
.note {
  margin: 22px 0 0;
  padding: 12px 14px;
  border: 1px solid var(--ink-18);
  font-size: 12.5px;
  line-height: 1.7;
}
.note .label { display: block; margin-bottom: 4px; }
.note p { margin: 0; }
.note p + p { margin-top: 8px; }

figcaption {
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--ink-50);
  margin-top: 8px;
  display: flex;
  gap: 8px;
}
figcaption .fignum { color: var(--ink); flex: none; }

kbd {
  font-family: var(--mono);
  font-size: 10px;
  border: 1px solid var(--ink-18);
  padding: 0 3px;
  color: var(--ink-70);
}

/* the layer map */
.stack { border: 1px solid var(--ink-18); margin: 22px 0 0; font-size: 12px; }
.stack .layer {
  padding: 6px 12px;
  border-bottom: 1px dotted var(--ink-18);
  display: flex;
  gap: 12px;
  align-items: baseline;
  transition: padding-left 0.2s var(--ease);
}
.stack .layer:last-child { border-bottom: 0; }
.stack .layer:hover { padding-left: 18px; }
.stack .layer .lname { font-weight: 600; min-width: 132px; }
.stack .layer .lnote { color: var(--ink-50); font-family: var(--mono); font-size: 10.5px; }
.stack .layer.here { background: var(--ink); color: var(--paper); }
.stack .layer.here .lnote { color: var(--paper); opacity: 0.65; }

/* ---------- buttons: square, mono, small ---------- */
.btn {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--ink-18);
  border-radius: 0;
  padding: 4px 9px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  -webkit-user-select: none;
  user-select: none;
}
.btn:hover { border-color: var(--ink); }
.btn.solid { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.btn:disabled { opacity: 0.28; cursor: not-allowed; }
.btn.sq { border-radius: 0; }

/* ---------- rig chrome ---------- */
.rig {
  margin: 24px 0 0;
  border: 1px solid var(--ink);
}
.rig-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 5px 10px;
  border-bottom: 1px solid var(--ink-18);
  background: var(--ink-04);
}
.rig-bar .title {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.rig-bar .dots { display: flex; gap: 4px; }
.rig-bar .dots i { width: 5px; height: 5px; border: 1px solid var(--ink-35); display: block; }
.rig-body { padding: 16px; }
.rig-foot {
  padding: 8px 10px;
  border-top: 1px dotted var(--ink-18);
  font-size: 11.5px;
  line-height: 1.6;
  color: var(--ink-70);
  display: flex;
  align-items: flex-start;
  gap: 8px;
}
.rig-foot .fignum {
  font-family: var(--mono);
  font-size: 9.5px;
  color: var(--ink);
  flex: none;
  border: 1px solid var(--ink-18);
  padding: 0 4px;
  margin-top: 2px;
}
.rig-foot .msg { min-width: 0; }
.rig-controls { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; }

/* toggle switch */
.switch {
  width: 40px; height: 20px;
  border: 1px solid var(--ink);
  border-radius: 0;
  position: relative;
  cursor: pointer;
  background: transparent;
  padding: 0;
  flex: none;
  transition: background 0.2s var(--ease);
}
.switch::after {
  content: "";
  position: absolute;
  top: 2px; left: 2px;
  width: 14px; height: 14px;
  background: var(--ink);
  transition: transform 0.22s var(--ease), background 0.2s;
}
.switch[aria-pressed="true"] { background: var(--ink); }
.switch[aria-pressed="true"]::after { transform: translateX(20px); background: var(--paper); }
.switch:focus-visible { outline: 1px solid var(--ink); outline-offset: 2px; }

/* bit cells */
.bits { display: flex; gap: 3px; flex-wrap: wrap; }
.bit {
  width: 32px; height: 38px;
  border: 1px solid var(--ink-18);
  border-radius: 0;
  background: transparent;
  color: var(--ink);
  font-family: var(--mono);
  font-size: 14px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1px;
  transition: background 0.18s var(--ease), color 0.18s, border-color 0.18s;
  padding: 0;
}
.bit small { font-size: 7.5px; color: var(--ink-35); }
.bit:hover:not(:disabled) { border-color: var(--ink); }
.bit.on { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.bit.on small { color: var(--paper); opacity: 0.6; }
.bit.flash { animation: flash 0.35s var(--ease); }
@keyframes flash { 0% { transform: scale(1.16); } 100% { transform: none; } }

.readout {
  font-family: var(--mono);
  font-size: 11px;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 16px;
  color: var(--ink-50);
}
.readout b { color: var(--ink); font-weight: 400; }
.big-num {
  font-family: var(--mono);
  font-size: 24px;
  letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
  line-height: 1.1;
}

/* truth table */
table.tt { border-collapse: collapse; font-family: var(--mono); font-size: 11px; width: 100%; }
table.tt th, table.tt td { border: 1px solid var(--ink-18); padding: 4px 7px; text-align: center; }
table.tt th { font-weight: 400; color: var(--ink-35); text-transform: uppercase; font-size: 9px; letter-spacing: 0.08em; }
table.tt tr.is-live td { background: var(--ink); color: var(--paper); border-color: var(--ink); }

/* svg diagrams */
svg.diagram { display: block; width: 100%; height: auto; overflow: visible; }
svg.diagram text { font-family: var(--mono); font-size: 9px; fill: var(--ink); letter-spacing: 0.03em; }
svg.diagram .wire { stroke: var(--ink-18); stroke-width: 1.25; fill: none; transition: stroke 0.2s var(--ease), stroke-width 0.2s; }
svg.diagram .wire.hot { stroke: var(--ink); stroke-width: 2.25; }
svg.diagram .shape { stroke: var(--ink); stroke-width: 1.25; fill: var(--paper); }
svg.diagram .fill-ink { fill: var(--ink); }
svg.diagram .muted { fill: var(--ink-50); }

/* rig 1: rows of a table */
.rows { display: flex; flex-wrap: wrap; gap: 3px; }
.row-cell {
  width: 34px;
  height: 26px;
  border: 1px solid var(--ink-18);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--mono);
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  transition: background 0.18s, color 0.18s, border-color 0.18s, opacity 0.18s;
}
.row-cell.visited { border-color: var(--ink); background: var(--ink-08); }
.row-cell.ruled-out { opacity: 0.22; }
.row-cell.found { background: var(--ink); color: var(--paper); border-color: var(--ink); opacity: 1; }

/* rig 2: index drawn as a tree */
svg.diagram .node-on { fill: var(--ink); stroke: var(--ink); }

/* rig 3: rows of a two-column index */
.idx-list { display: flex; flex-direction: column; border: 1px solid var(--ink-18); }
.idx-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  padding: 3px 9px;
  font-family: var(--mono);
  font-size: 11px;
  border-bottom: 1px dotted var(--ink-08);
  transition: background 0.18s, color 0.18s, opacity 0.18s;
}
.idx-row:last-child { border-bottom: 0; }
.idx-row .f { color: var(--ink-50); }
.idx-row.dim { opacity: 0.3; }
.idx-row.match { background: var(--ink); color: var(--paper); opacity: 1; }
.idx-row.match .f { color: var(--paper); opacity: 0.7; }

input[type="range"] { accent-color: var(--ink); height: 12px; }

/* ---------- reveal ---------- */
.rise { opacity: 0; transform: translateY(10px); transition: opacity 0.5s var(--ease), transform 0.5s var(--ease); }
.rise.in { opacity: 1; transform: none; }

.reveal-chars .ch {
  display: inline-block;
  opacity: 0;
  transform: translateY(0.35em);
  animation: charIn 0.5s var(--ease) forwards;
}
@keyframes charIn { to { opacity: 1; transform: none; } }

/* ---------- command palette ---------- */
.cmd-scrim {
  position: fixed;
  inset: 0;
  background: var(--paper);
  opacity: 0;
  pointer-events: none;
  z-index: 200;
  transition: opacity 0.18s;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 14vh 20px;
}
.cmd-scrim.open { opacity: 0.98; pointer-events: auto; }
.cmd { width: min(460px, 100%); border: 1px solid var(--ink); background: var(--paper); }
.cmd input {
  width: 100%;
  border: 0;
  border-bottom: 1px solid var(--ink-18);
  background: transparent;
  color: var(--ink);
  font-family: var(--mono);
  font-size: 12px;
  padding: 9px 11px;
  outline: none;
}
.cmd input::placeholder { color: var(--ink-35); }
.cmd-list { max-height: 44vh; overflow-y: auto; }
.cmd-list button {
  width: 100%;
  text-align: left;
  border: 0;
  background: transparent;
  color: inherit;
  font-family: var(--mono);
  font-size: 11.5px;
  padding: 6px 11px;
  cursor: pointer;
  display: flex;
  align-items: baseline;
  gap: 8px;
}
.cmd-list button .hint { margin-left: auto; font-size: 9.5px; color: var(--ink-35); }
.cmd-list button[aria-selected="true"] { background: var(--ink); color: var(--paper); }
.cmd-list button[aria-selected="true"] .hint { color: var(--paper); opacity: 0.65; }
.cmd-foot {
  border-top: 1px dotted var(--ink-18);
  padding: 6px 11px;
  display: flex;
  gap: 12px;
  font-family: var(--mono);
  font-size: 9.5px;
  color: var(--ink-35);
}

/* ---------- guides: part dividers and contents ---------- */
.section-note {
  font-size: 12.5px;
  color: var(--ink-70);
  max-width: 62ch;
  margin: 0 0 24px;
}

.toc {
  margin: 26px 0 0;
  padding: 12px 14px;
  border: 1px solid var(--ink-18);
}
.toc ol {
  margin: 8px 0 0;
  padding-left: 20px;
  font-size: 12.5px;
}
.toc li { margin: 3px 0; }
.toc li::marker { font-family: var(--mono); font-size: 10px; color: var(--ink-35); }
.toc a { text-decoration-color: var(--ink-18); }

.part {
  margin: 72px 0 0;
  padding: 10px 0 9px;
  border-top: 2px solid var(--ink);
  border-bottom: 1px solid var(--ink-18);
  display: flex;
  align-items: baseline;
  gap: 12px;
  scroll-margin-top: 20px;
}
.part span {
  font-family: var(--mono);
  font-size: 9.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-35);
  flex: none;
}
.part b {
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.015em;
}
/* the first h2 after a part divider should sit close, not 56px away */
.part + h2 { margin-top: 26px; border-top: 0; padding-top: 0; }

/* ---------- responsive ---------- */
@media (max-width: 680px) {
  .wrap { padding: 22px 18px 80px; }
  .ram { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .cpu-grid { grid-template-columns: 1fr; }
  .g-wrap { grid-template-columns: 1fr !important; }
  .stack .layer { flex-direction: column; gap: 1px; }
  .stack .layer .lname { min-width: 0; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
  .rise { opacity: 1; transform: none; }
  .reveal-chars .ch { opacity: 1; transform: none; }
  .menu .caret { animation: none; }
}

/* ---------- hive: an idea page ---------- */
/* the facts strip under the title. who, when, what shape the thing is.
   same border language as .stack, but keyed rather than layered. */
.facts {
  border: 1px solid var(--ink-18);
  margin: 22px 0 0;
  font-size: 12px;
}
.facts .f {
  display: flex;
  gap: 12px;
  align-items: baseline;
  padding: 6px 12px;
  border-bottom: 1px dotted var(--ink-18);
}
.facts .f:last-child { border-bottom: 0; }
.facts .k {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-50);
  min-width: 108px;
  flex: none;
}
.facts .v { min-width: 0; }

/* the one-paragraph version, sitting above the long version */
.summary {
  margin: 26px 0 0;
  padding: 14px 16px;
  border: 1px solid var(--ink);
  font-size: 13.5px;
  line-height: 1.7;
}
.summary .label { display: block; margin-bottom: 6px; }
.summary p { margin: 0; }
.summary p + p { margin-top: 10px; }

/* status of an idea: nothing here is a promise to build */
.stamp {
  font-family: var(--mono);
  font-size: 9.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  border: 1px solid var(--ink-18);
  padding: 1px 5px;
  color: var(--ink-50);
}