/* KEEL — one pager
   Editorial, file-native, no framework.
   Type: Instrument Serif / IBM Plex Sans / IBM Plex Mono
*/

:root {
  --ink: #0c0d0b;
  --paper: #efe9dc;
  --paper-dim: #cfc7b6;
  --bg: #04181e;
  --bg-2: #072a33;
  --surface: #FFF9F2;
  --brass: #a68b5b;
  --brass-bright: #c4b08a;
  --signal: #8fbf7a;
  --signal-dim: #5e8a4e;
  --danger: #c45c4a;
  --rule: rgba(239, 233, 220, 0.12);
  --rule-strong: rgba(239, 233, 220, 0.22);
  --shade: rgba(239, 233, 220, 0.06);
  --serif: "Instrument Serif", "Iowan Old Style", "Palatino Linotype", Palatino, serif;
  --sans: "IBM Plex Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --mono: "IBM Plex Mono", "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --nav-h: 4.5rem;
  --gutter: clamp(1.25rem, 4vw, 3.5rem);
  --max: 1180px;
  --keel: 1px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--bg);
}

html.lenis,
html.lenis body {
  height: auto;
}

body {
  margin: 0;
  color: var(--paper);
  background: var(--bg);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  font-weight: 400;
  letter-spacing: -0.011em;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img,
svg {
  display: block;
  max-width: 100%;
}

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

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

/* Grain + keel rail ------------------------------------------------------- */

.grain {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 80;
  opacity: 0.055;
  mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='4' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 1  0 0 0 0 1  0 0 0 0 1  0 0 0 .7 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
}

.keel-rail {
  pointer-events: none;
  position: fixed;
  top: 0;
  bottom: 0;
  left: max(1.1rem, calc((100vw - var(--max)) / 2 - 2.2rem));
  width: var(--keel);
  background: linear-gradient(to bottom, transparent, var(--brass) 12%, var(--brass) 88%, transparent);
  opacity: 0.55;
  z-index: 40;
}

.keel-rail::before {
  content: "";
  position: absolute;
  left: -3px;
  top: 0;
  width: 7px;
  height: var(--progress, 0%);
  background: var(--surface);
  opacity: 0.85;
  transform-origin: top;
}

@media (max-width: 860px) {
  .keel-rail {
    left: 0.7rem;
    opacity: 0.28;
  }
}

/* Nav --------------------------------------------------------------------- */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--gutter);
  mix-blend-mode: difference;
  color: var(--paper);
  transition: transform 0.5s var(--ease), opacity 0.4s ease;
}

.nav.is-hidden {
  transform: translateY(-110%);
  opacity: 0;
}

.nav-mark {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
}

.nav-mark svg {
  width: 18px;
  height: 18px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.6rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.nav-links a {
  opacity: 0.72;
  transition: opacity 0.25s ease;
}

.nav-links a:hover,
.nav-links a:focus-visible {
  opacity: 1;
}

.nav-cta {
  border: 1px solid currentColor;
  padding: 0.45rem 0.75rem;
  opacity: 1 !important;
}

/* Layout ------------------------------------------------------------------ */

.wrap {
  width: min(100% - 2 * var(--gutter), var(--max));
  margin-inline: auto;
}

.section {
  position: relative;
  padding: clamp(4.5rem, 10vw, 8.5rem) 0;
}

.section-kicker {
  display: flex;
  align-items: baseline;
  gap: 0.85rem;
  margin-bottom: 1.4rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--brass-bright);
}

.section-kicker .idx {
  opacity: 0.55;
}

hr.rule {
  border: 0;
  height: 1px;
  background: var(--rule);
  margin: 0;
}

/* Hero -------------------------------------------------------------------- */

.hero {
  padding: calc(var(--nav-h) + 0.4rem) 0 2.4rem;
  position: relative;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem 1.4rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--paper-dim);
  margin-bottom: 1.6rem;
}

.hero-meta .dot {
  color: var(--signal);
}

.hero h1 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(3.4rem, 11.4vw, 9.4rem);
  line-height: 0.88;
  letter-spacing: -0.03em;
  margin: 0 0 1.6rem;
}

.hero h1 em {
  font-style: italic;
  font-weight: 400;
  color: var(--brass-bright);
}

.hero-lede {
  max-width: 36rem;
  font-size: clamp(1.05rem, 1.7vw, 1.28rem);
  color: var(--paper-dim);
  margin: 0 0 2.4rem;
}

.hero-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: stretch;
  margin-bottom: 2.6rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  min-height: 2.9rem;
  padding: 0 1.15rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  border: 1px solid var(--paper);
  transition: background 0.25s ease, color 0.25s ease, border-color 0.25s ease;
}

.btn-solid {
  background: var(--surface);
  color: var(--ink);
}

.btn-solid:hover,
.btn-solid:focus-visible {
  background: var(--brass-bright);
  border-color: var(--brass-bright);
}

.btn-ghost:hover,
.btn-ghost:focus-visible {
  background: var(--surface);
  color: var(--ink);
}

.boot {
  flex: 1 1 22rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-height: 2.9rem;
  padding: 0 0.95rem;
  border: 1px solid var(--rule-strong);
  background: var(--bg-2);
  font-family: var(--mono);
  font-size: clamp(0.68rem, 1.4vw, 0.82rem);
  letter-spacing: 0.02em;
  color: var(--signal);
  overflow: hidden;
  white-space: nowrap;
}

.boot .caret {
  display: inline-block;
  width: 0.5ch;
  height: 1.05em;
  background: var(--signal);
  transform: translateY(2px);
  animation: blink 1.05s steps(1) infinite;
}

@keyframes blink {
  50% { opacity: 0; }
}

.hero-foot {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1.4rem;
  align-items: end;
  padding-top: 1.6rem;
  border-top: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--paper-dim);
}

.scroll-hint {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.scroll-hint i {
  display: block;
  width: 11px;
  height: 18px;
  border: 1px solid currentColor;
  border-radius: 8px;
  position: relative;
}

.scroll-hint i::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 3px;
  width: 2px;
  height: 4px;
  background: currentColor;
  transform: translateX(-50%);
  animation: wheel 1.6s var(--ease) infinite;
}

@keyframes wheel {
  0% { opacity: 1; transform: translateX(-50%) translateY(0); }
  100% { opacity: 0; transform: translateX(-50%) translateY(7px); }
}

/* Overview shot ----------------------------------------------------------- */

.shot-section {
  padding-top: 0;
}

.shot {
  margin: 0;
  border: 1px solid var(--rule-strong);
  background: var(--bg-2);
  overflow: hidden;
}

.shot-chrome {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.7rem 0.9rem;
  border-bottom: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--paper-dim);
}

.shot-chrome i {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--rule-strong);
}

.shot-chrome i:nth-child(1) { background: #c45c4a; }
.shot-chrome i:nth-child(2) { background: var(--brass); }
.shot-chrome i:nth-child(3) { background: var(--signal-dim); }

.shot-chrome span {
  margin-left: 0.5rem;
}

.ov {
  background: #f7f7f5;
  color: #1a1a1a;
  padding: 1.35rem 1.4rem 1.5rem;
  font-family: -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 13px;
  line-height: 1.4;
}

.ov-head h3 {
  margin: 0;
  font-size: 1.15rem;
  font-weight: 650;
  letter-spacing: -0.02em;
  color: #1a1a1a;
}

.ov-head p {
  margin: 0.2rem 0 0.9rem;
  color: #666;
  font-size: 12px;
}

.ov-head em {
  font-style: normal;
  font-size: 11px;
  padding: 1px 7px;
  border: 1px solid #ccc;
  border-radius: 9px;
  color: #555;
}

.ov-block {
  margin-bottom: 0.95rem;
}

.ov-block h4 {
  margin: 0 0 0.4rem;
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #888;
  border-bottom: 1px solid #ddd;
  padding-bottom: 4px;
}

.ov-quiet {
  margin: 0;
  color: #666;
  font-size: 13px;
}

.ov table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  border: 1px solid #ddd;
  font-size: 13px;
}

.ov th,
.ov td {
  text-align: left;
  padding: 6px 10px;
  border-bottom: 1px solid #eee;
}

.ov th {
  background: #fafafa;
  font-weight: 600;
  font-size: 11px;
  color: #555;
}

.ov-split {
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: 1rem;
}

.ov-cue {
  margin: 0;
  background: #fffbe6;
  border: 1px solid #e6d24c;
  padding: 8px 10px;
  font-size: 13px;
  color: #1a1a1a;
}

.ov-stories {
  list-style: none;
  margin: 0;
  padding: 0;
  border: 1px solid #ddd;
  background: #fff;
}

.ov-stories li {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 7px 10px;
  border-bottom: 1px solid #eee;
  font-size: 13px;
  color: #1a1a1a;
}

.ov-stories li:last-child {
  border-bottom: 0;
}

.ov-stories span {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 12px;
  color: #0a58ca;
  min-width: 3.4rem;
}

.ov-stories b {
  margin-left: auto;
  font-size: 11px;
  font-weight: 500;
  padding: 1px 7px;
  border-radius: 9px;
  border: 1px solid #ccc;
  color: #999;
  background: #f1f1f1;
}

.shot-pic {
  display: block;
  line-height: 0;
  background: #1a1a1a;
}

.shot-pic img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 1600 / 874;
  object-fit: contain;
  object-position: top center;
}

.shot figcaption {
  padding: 0.85rem 1rem 1rem;
  font-size: 0.88rem;
  color: var(--paper-dim);
}

.shot figcaption code {
  font-family: var(--mono);
  font-size: 0.86em;
  color: var(--paper);
}

/* Split thesis ------------------------------------------------------------ */

.thesis {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.thesis article {
  padding: clamp(2.2rem, 5vw, 4rem) clamp(1.4rem, 3vw, 2.6rem);
}

.thesis article:first-child {
  border-right: 1px solid var(--rule);
}

.thesis h2 {
  font-family: var(--serif);
  font-size: clamp(2rem, 4.4vw, 3.4rem);
  font-weight: 400;
  letter-spacing: -0.03em;
  line-height: 1;
  margin: 0 0 1.1rem;
}

.thesis p {
  margin: 0;
  max-width: 34em;
  color: var(--paper-dim);
}

.thesis .invert {
  background: var(--surface);
  color: var(--ink);
}

.thesis .invert p {
  color: #3d3a33;
}

code.inline {
  font-family: var(--mono);
  font-size: 0.86em;
  color: var(--paper);
}

/* Benefits ---------------------------------------------------------------- */

.benefits {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.benefit {
  background: var(--bg);
  padding: 1.5rem 1.35rem 1.65rem;
  min-height: 13.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  transition: background 0.35s ease;
}

.benefit:hover {
  background: var(--bg-2);
}

.benefit .n {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.18em;
  color: var(--brass-bright);
}

.benefit h3 {
  font-family: var(--serif);
  font-size: 1.55rem;
  font-weight: 400;
  letter-spacing: -0.02em;
  margin: 0;
  line-height: 1.1;
}

.benefit p {
  margin: 0;
  color: var(--paper-dim);
  font-size: 0.92rem;
}

.benefit code {
  font-family: var(--mono);
  font-size: 0.86em;
  color: var(--paper);
}

/* Loop -------------------------------------------------------------------- */

.loop-head {
  display: grid;
  grid-template-columns: 1fr minmax(0, 28rem);
  gap: 2rem;
  margin-bottom: 3rem;
}

.loop-head h2 {
  font-family: var(--serif);
  font-size: clamp(2.6rem, 6vw, 5.2rem);
  font-weight: 400;
  letter-spacing: -0.03em;
  line-height: 0.92;
  margin: 0;
}

.loop-head p {
  margin: 0.4rem 0 0;
  color: var(--paper-dim);
  font-size: 1.05rem;
}

.steps {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0;
  border: 1px solid var(--rule);
}

.step {
  padding: 1.4rem 1.2rem 1.6rem;
  border-right: 1px solid var(--rule);
  min-height: 16.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  background: transparent;
  transition: background 0.4s ease;
}

.step:last-child {
  border-right: 0;
}

.step:hover {
  background: var(--shade);
}

.step .n {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.18em;
  color: var(--brass-bright);
}

.step h3 {
  font-family: var(--serif);
  font-size: 1.7rem;
  font-weight: 400;
  letter-spacing: -0.02em;
  margin: 0;
  line-height: 1.05;
}

.step p {
  margin: 0;
  color: var(--paper-dim);
  font-size: 0.92rem;
  flex: 1;
}

.step code {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--paper);
  letter-spacing: 0.04em;
  opacity: 0.8;
}

/* Artifacts --------------------------------------------------------------- */

.files {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.file {
  background: var(--bg);
  padding: 1.5rem 1.35rem 1.6rem;
  min-height: 11.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  transition: background 0.35s ease;
}

.file:hover {
  background: var(--bg-2);
}

.file .path {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  color: var(--brass-bright);
}

.file h3 {
  font-size: 1.05rem;
  font-weight: 500;
  margin: 0;
  letter-spacing: -0.02em;
}

.file p {
  margin: 0;
  color: var(--paper-dim);
  font-size: 0.9rem;
}

.file .mut {
  margin-top: auto;
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--paper-dim);
}

/* Invariants -------------------------------------------------------------- */

.invariants {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.3fr);
  gap: clamp(2rem, 5vw, 4.5rem);
  align-items: start;
}

.invariants h2 {
  font-family: var(--serif);
  font-size: clamp(2.4rem, 5vw, 4.4rem);
  font-weight: 400;
  letter-spacing: -0.03em;
  line-height: 0.94;
  margin: 0 0 1rem;
  position: sticky;
  top: 6rem;
}

.invariants .lede {
  color: var(--paper-dim);
  max-width: 28rem;
}

.law-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--rule);
}

.law-list li {
  display: grid;
  grid-template-columns: 3.2rem 1fr;
  gap: 0.8rem;
  padding: 1.05rem 0;
  border-bottom: 1px solid var(--rule);
  font-size: 1.02rem;
}

.law-list .n {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--brass-bright);
  padding-top: 0.28rem;
}

/* Quote band -------------------------------------------------------------- */

.verdict {
  padding: clamp(4rem, 9vw, 7.5rem) 0;
  background: var(--surface);
  color: var(--ink);
}

.verdict blockquote {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.1rem, 5.4vw, 4.4rem);
  line-height: 1.02;
  letter-spacing: -0.03em;
  font-weight: 400;
  max-width: 16ch;
}

.verdict blockquote em {
  font-style: italic;
}

.verdict .note {
  margin-top: 1.6rem;
  max-width: 36rem;
  color: #4a463c;
  font-size: 1.02rem;
}

/* Evidence ---------------------------------------------------------------- */

.prove-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
  margin-bottom: 1.4rem;
}

.prove {
  background: var(--bg);
  padding: 1.5rem 1.4rem 1.6rem;
}

.prove h3 {
  font-family: var(--serif);
  font-size: 1.7rem;
  font-weight: 400;
  letter-spacing: -0.02em;
  margin: 0 0 0.25rem;
}

.prove-note {
  margin: 0 0 1.1rem;
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--brass-bright);
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--rule);
}

table.matrix {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  min-width: 720px;
}

.matrix th,
.matrix td {
  text-align: left;
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
}

.matrix th {
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--paper-dim);
  font-weight: 500;
  background: var(--bg-2);
}

.matrix tr:last-child td {
  border-bottom: 0;
}

.matrix td:first-child {
  font-family: var(--mono);
  color: var(--brass-bright);
  width: 2.4rem;
}

.pass {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--signal);
}

.gates {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
  margin-top: 1.4rem;
}

.gate {
  background: var(--bg);
  padding: 1.2rem 1.1rem 1.3rem;
}

.gate h3 {
  margin: 0 0 0.45rem;
  font-size: 0.95rem;
  font-weight: 500;
}

.gate p {
  margin: 0;
  color: var(--paper-dim);
  font-size: 0.86rem;
}

/* Start ------------------------------------------------------------------- */

.start-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: clamp(1.6rem, 4vw, 3.2rem);
  align-items: start;
}

.start-grid h2 {
  font-family: var(--serif);
  font-size: clamp(2.4rem, 5vw, 4.2rem);
  font-weight: 400;
  letter-spacing: -0.03em;
  line-height: 0.94;
  margin: 0 0 1rem;
}

.terminal {
  background: var(--bg-2);
  border: 1px solid var(--rule-strong);
  padding: 0;
}

.terminal-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.65rem 0.9rem;
  border-bottom: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--paper-dim);
}

.copy {
  border: 1px solid var(--rule-strong);
  padding: 0.25rem 0.55rem;
  letter-spacing: 0.12em;
  transition: background 0.2s ease, color 0.2s ease;
}

.copy:hover,
.copy.is-done {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--surface);
}

.terminal pre {
  margin: 0;
  padding: 1.15rem 1.1rem 1.3rem;
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.7;
  overflow-x: auto;
  color: var(--paper);
}

.terminal .cmt {
  color: var(--brass);
}

.facts {
  list-style: none;
  margin: 1.6rem 0 0;
  padding: 0;
}

.facts li {
  display: flex;
  gap: 0.8rem;
  padding: 0.7rem 0;
  border-top: 1px solid var(--rule);
  font-size: 0.95rem;
  color: var(--paper-dim);
}

.facts strong {
  color: var(--paper);
  font-weight: 500;
}

.aside {
  border: 1px solid var(--rule);
  padding: 1.4rem 1.3rem 1.5rem;
}

.aside h3 {
  font-family: var(--serif);
  font-size: 1.7rem;
  font-weight: 400;
  margin: 0 0 0.7rem;
}

.aside p {
  margin: 0 0 1.1rem;
  color: var(--paper-dim);
  font-size: 0.95rem;
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.chip {
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  border: 1px solid var(--rule-strong);
  padding: 0.35rem 0.55rem;
  color: var(--paper-dim);
}

/* Footer ------------------------------------------------------------------ */

.foot {
  padding: 2rem 0 2.6rem;
  border-top: 1px solid var(--rule);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--paper-dim);
}

.foot a:hover {
  color: var(--paper);
}

/* Reveal ------------------------------------------------------------------ */

.reveal {
  opacity: 0;
  transform: translateY(18px);
  animation: rise 0.9s var(--ease) forwards;
}

.reveal-d1 { animation-delay: 0.08s; }
.reveal-d2 { animation-delay: 0.18s; }
.reveal-d3 { animation-delay: 0.3s; }
.reveal-d4 { animation-delay: 0.42s; }

@keyframes rise {
  to {
    opacity: 1;
    transform: none;
  }
}

.in-view {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.8s var(--ease), transform 0.8s var(--ease);
}

.in-view.is-on {
  opacity: 1;
  transform: none;
}

/* Responsive -------------------------------------------------------------- */

@media (max-width: 980px) {
  .steps {
    grid-template-columns: 1fr 1fr;
  }
  .step:nth-child(2n) {
    border-right: 0;
  }
  .step:nth-child(-n + 4) {
    border-bottom: 1px solid var(--rule);
  }
  .files {
    grid-template-columns: 1fr 1fr;
  }
  .invariants,
  .loop-head,
  .start-grid {
    grid-template-columns: 1fr;
  }
  .invariants h2 {
    position: static;
  }
  .gates {
    grid-template-columns: 1fr 1fr;
  }
  .benefits {
    grid-template-columns: 1fr 1fr;
  }
  .prove-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .nav-links a:not(.nav-cta) {
    display: none;
  }
  .thesis {
    grid-template-columns: 1fr;
  }
  .thesis article:first-child {
    border-right: 0;
    border-bottom: 1px solid var(--rule);
  }
  .steps {
    grid-template-columns: 1fr;
  }
  .step {
    border-right: 0;
    border-bottom: 1px solid var(--rule);
    min-height: 0;
  }
  .step:last-child {
    border-bottom: 0;
  }
  .files,
  .gates,
  .benefits {
    grid-template-columns: 1fr;
  }
  .hero-foot {
    grid-template-columns: 1fr;
  }
  .boot {
    white-space: normal;
  }
  .ov-split {
    grid-template-columns: 1fr;
  }
  .shot-chrome span {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    min-width: 0;
  }
}

/* Hero version chip ---------------------------------------------------- */

.hero-version {
  margin-left: auto;
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.18em;
  color: var(--brass-bright);
  border: 1px solid var(--rule-strong);
  padding: 0.25rem 0.55rem;
}

/* Overview mock — extras ----------------------------------------------- */

.ov-ok {
  color: var(--signal);
  font-weight: 500;
}

.ov-decisions,
.ov-epics {
  list-style: none;
  margin: 0;
  padding: 0;
  border: 1px solid #ddd;
  background: #fff;
}

.ov-decisions li,
.ov-epics li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 6px 10px;
  border-bottom: 1px solid #eee;
  font-size: 12.5px;
  color: #1a1a1a;
}

.ov-decisions li:last-child,
.ov-epics li:last-child {
  border-bottom: 0;
}

.ov-decisions span,
.ov-epics span {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 11.5px;
  color: #0a58ca;
  min-width: 5.2rem;
}

.ov-decisions b {
  margin-left: auto;
  font-size: 10.5px;
  font-weight: 500;
  padding: 1px 7px;
  border-radius: 9px;
  border: 1px solid #ccc;
  color: #555;
  background: #fafafa;
}

.ov-epics em {
  margin-left: auto;
  font-style: normal;
  font-size: 11.5px;
  color: #555;
}

.ov-epics .ov-backlog {
  color: #b34a00;
  font-weight: 600;
}

.ov-epics code {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 11.5px;
  color: #0a58ca;
}

/* Two guides ----------------------------------------------------------- */

.two-guides .guides {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
  margin-top: 1.6rem;
}

.guide {
  background: var(--bg);
  padding: 1.5rem 1.4rem 1.7rem;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  color: var(--paper);
  transition: background 0.3s ease;
}

.guide:hover,
.guide:focus-visible {
  background: var(--bg-2);
}

.guide-tag {
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--brass-bright);
}

.guide h3 {
  font-family: var(--serif);
  font-size: 1.6rem;
  font-weight: 400;
  letter-spacing: -0.02em;
  margin: 0;
  line-height: 1.1;
}

.guide p {
  margin: 0;
  color: var(--paper-dim);
  font-size: 0.92rem;
}

.guide-cta {
  margin-top: auto;
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--signal);
}

/* Epic strip (α — two extra beats on top of the canonical five) -------- */

.epic-strip {
  margin-top: 2.4rem;
  padding-top: 1.6rem;
  border-top: 1px solid var(--rule);
}

.epic-strip-head h3 {
  font-family: var(--serif);
  font-size: clamp(1.7rem, 3.4vw, 2.6rem);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.05;
  margin: 0.3rem 0 0.6rem;
}

.epic-strip-head p {
  margin: 0;
  color: var(--paper-dim);
  font-size: 0.98rem;
  max-width: 56ch;
}

.epic-strip-beats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
  margin-top: 1.6rem;
}

.epic-beat {
  background: var(--bg);
  padding: 1.3rem 1.2rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}

.epic-beat .n {
  font-family: var(--mono);
  font-size: 0.66rem;
  letter-spacing: 0.18em;
  color: var(--brass-bright);
}

.epic-beat h4 {
  font-family: var(--serif);
  font-size: 1.4rem;
  font-weight: 400;
  letter-spacing: -0.02em;
  margin: 0;
  line-height: 1.1;
}

.epic-beat p {
  margin: 0;
  color: var(--paper-dim);
  font-size: 0.9rem;
}

.epic-beat code {
  font-family: var(--mono);
  font-size: 0.74rem;
  color: var(--paper);
  letter-spacing: 0.04em;
  opacity: 0.85;
}

/* Docs rail ----------------------------------------------------------- */

.docs-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.doc-card {
  background: var(--bg);
  padding: 1.3rem 1.2rem 1.4rem;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  color: var(--paper);
  transition: background 0.3s ease;
  min-height: 11.5rem;
}

.doc-card:hover,
.doc-card:focus-visible {
  background: var(--bg-2);
}

.doc-tag {
  font-family: var(--mono);
  font-size: 0.6rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--brass-bright);
}

.doc-card h3 {
  font-size: 1.05rem;
  font-weight: 500;
  letter-spacing: -0.02em;
  margin: 0;
}

.doc-card p {
  margin: 0;
  color: var(--paper-dim);
  font-size: 0.86rem;
}

.doc-card code {
  font-family: var(--mono);
  font-size: 0.86em;
  color: var(--paper);
}

/* Responsive additions (merge with existing 980 / 720 media) -------- */

@media (max-width: 980px) {
  .two-guides .guides,
  .epic-strip-beats,
  .docs-grid {
    grid-template-columns: 1fr 1fr;
  }
  .hero-meta .hero-version {
    margin-left: 0;
  }
}

@media (max-width: 720px) {
  .two-guides .guides,
  .epic-strip-beats,
  .docs-grid {
    grid-template-columns: 1fr;
  }
  .epic-strip-beats .epic-beat + .epic-beat {
    border-top: 1px solid var(--rule);
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal,
  .in-view,
  .scroll-hint i::after,
  .boot .caret {
    animation: none !important;
    transition: none !important;
    opacity: 1 !important;
    transform: none !important;
  }
}

:focus-visible {
  outline: 1px solid var(--brass-bright);
  outline-offset: 3px;
}