:root {
  --ink: #171815;
  --ink-soft: #5d6057;
  --paper: #f2efe5;
  --paper-bright: #fbf9f2;
  --rail: #191b18;
  --rail-soft: #a9aa9f;
  --signal: #d8ff3e;
  --oxide: #d24a2f;
  --line: rgba(23, 24, 21, 0.16);
  --code: #11130f;
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, monospace;
  --serif: "Newsreader", Georgia, serif;
  --rail-width: 320px;
  --topbar-height: 62px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.72;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.18;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.09'/%3E%3C/svg%3E");
  z-index: 20;
}

a { color: inherit; }

.reading-progress {
  position: fixed;
  inset: 0 0 auto;
  height: 3px;
  z-index: 100;
  background: transparent;
}

.reading-progress span {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--signal);
  transform: scaleX(0);
  transform-origin: left;
}

.topbar {
  position: fixed;
  inset: 0 0 auto;
  height: var(--topbar-height);
  display: grid;
  grid-template-columns: var(--rail-width) 1fr auto;
  align-items: center;
  z-index: 40;
  color: #f5f3e9;
  background: var(--rail);
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
}

.wordmark {
  height: 100%;
  display: flex;
  align-items: center;
  padding: 0 26px;
  text-decoration: none;
  border-right: 1px solid rgba(255, 255, 255, 0.12);
  font-weight: 600;
}

.wordmark span { color: var(--signal); }

.topbar-meta {
  display: flex;
  gap: 24px;
  padding: 0 26px;
  color: var(--rail-soft);
}

.portfolio-link {
  align-self: stretch;
  display: flex;
  align-items: center;
  padding: 0 24px;
  color: var(--ink);
  background: var(--signal);
  text-decoration: none;
  font-weight: 600;
}

.portfolio-link:hover { background: #e4ff74; }

.menu-button {
  display: none;
  border: 0;
  background: transparent;
  color: inherit;
}

.sidebar {
  position: fixed;
  inset: var(--topbar-height) auto 0 0;
  width: var(--rail-width);
  display: flex;
  flex-direction: column;
  z-index: 35;
  overflow: hidden;
  color: #f4f2e8;
  background:
    linear-gradient(160deg, rgba(216, 255, 62, 0.045), transparent 38%),
    var(--rail);
  border-right: 1px solid rgba(255, 255, 255, 0.1);
}

.sidebar-head {
  padding: 30px 26px 24px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.11);
}

.sidebar-head p {
  margin: 0 0 10px;
  color: var(--signal);
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.sidebar-head h1 {
  margin: 0 0 22px;
  font-family: var(--serif);
  font-size: 2.05rem;
  line-height: 0.94;
  letter-spacing: -0.045em;
}

.search-label span {
  display: block;
  margin-bottom: 6px;
  color: var(--rail-soft);
  font-family: var(--mono);
  font-size: 0.58rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

#chapter-search {
  width: 100%;
  padding: 10px 12px;
  color: #fff;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 2px;
  outline: none;
  font: 0.72rem var(--mono);
}

#chapter-search:focus { border-color: var(--signal); }

.chapter-nav {
  flex: 1;
  overflow-y: auto;
  padding: 18px 14px 26px;
  scrollbar-color: rgba(255,255,255,.25) transparent;
  scrollbar-width: thin;
}

.nav-section { margin: 0 0 24px; }
.nav-section[hidden],
.nav-link[hidden] { display: none; }

.nav-section h2 {
  margin: 0 12px 7px;
  color: #74776d;
  font-family: var(--mono);
  font-size: 0.56rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.nav-link {
  display: block;
  padding: 7px 12px;
  color: #bfc0b7;
  border-left: 2px solid transparent;
  text-decoration: none;
  font: 0.7rem/1.45 var(--mono);
  transition: color 120ms ease, background 120ms ease, border-color 120ms ease;
}

.nav-link:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.04);
}

.nav-link.is-active {
  color: var(--signal);
  border-left-color: var(--signal);
  background: rgba(216, 255, 62, 0.06);
}

.sidebar-foot {
  display: flex;
  justify-content: space-between;
  padding: 14px 26px;
  color: #797c73;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font: 0.55rem var(--mono);
}

.sidebar-foot a { text-decoration: none; }
.sidebar-foot a:hover { color: var(--signal); }

.nav-scrim { display: none; }

.reading-pane {
  min-height: 100vh;
  margin-left: var(--rail-width);
  padding-top: var(--topbar-height);
  background:
    linear-gradient(90deg, transparent 0, transparent calc(100% - 1px), var(--line) 100%) 0 0 / 9.5rem 100%,
    var(--paper);
}

.content-shell {
  width: min(850px, calc(100% - 84px));
  margin: 0 auto;
  padding: 68px 0 54px;
}

.page-coordinate {
  display: flex;
  justify-content: space-between;
  margin-bottom: 54px;
  padding-bottom: 12px;
  color: var(--ink-soft);
  border-bottom: 1px solid var(--ink);
  font: 0.64rem var(--mono);
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.briefing-strip {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  margin: -20px 0 52px;
  color: #f5f3e9;
  background: var(--ink);
  border-top: 4px solid var(--signal);
}

.briefing-strip span {
  padding: 22px;
  border-right: 1px solid rgba(255, 255, 255, 0.14);
  font: 0.68rem var(--mono);
  text-transform: uppercase;
}

.briefing-strip span:last-child { border-right: 0; }

.briefing-strip b {
  display: block;
  color: var(--signal);
  font: 2rem/1 var(--serif);
}

.prose > h1:first-child {
  max-width: 760px;
  margin: 0 0 34px;
  font-size: clamp(3.4rem, 7vw, 6.5rem);
  line-height: 0.88;
  letter-spacing: -0.065em;
}

.prose h2 {
  margin: 4.8rem 0 1.35rem;
  padding-top: 0.85rem;
  border-top: 2px solid var(--ink);
  font-size: clamp(2rem, 4vw, 3.1rem);
  line-height: 1;
  letter-spacing: -0.04em;
}

.prose h3 {
  margin: 2.8rem 0 0.8rem;
  color: var(--oxide);
  font-family: var(--mono);
  font-size: 0.82rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.prose h4 {
  margin: 2.2rem 0 0.7rem;
  font-size: 1.2rem;
}

.prose p { margin: 0 0 1.35rem; }

.prose > p:first-of-type {
  font-size: 1.32rem;
  line-height: 1.55;
}

.prose a {
  text-decoration-color: var(--oxide);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.prose a:hover { color: var(--oxide); }

.prose ul,
.prose ol {
  margin: 0 0 1.6rem;
  padding-left: 1.4rem;
}

.prose li { margin-bottom: 0.48rem; padding-left: 0.25rem; }

.prose li::marker {
  color: var(--oxide);
  font-family: var(--mono);
  font-weight: 600;
}

.prose blockquote {
  margin: 2.4rem 0;
  padding: 22px 26px;
  background: var(--paper-bright);
  border: 1px solid var(--line);
  border-left: 6px solid var(--oxide);
  box-shadow: 8px 8px 0 rgba(23, 24, 21, 0.06);
}

.prose blockquote p:last-child { margin-bottom: 0; }

.prose code {
  padding: 0.12em 0.32em;
  background: rgba(23, 24, 21, 0.08);
  border-radius: 2px;
  font: 0.82em var(--mono);
}

.prose pre {
  position: relative;
  margin: 2rem 0;
  padding: 24px 26px;
  overflow-x: auto;
  color: #e9eadf;
  background: var(--code);
  border-top: 4px solid var(--signal);
  box-shadow: 10px 10px 0 rgba(23, 24, 21, 0.11);
}

.prose pre code {
  padding: 0;
  color: inherit;
  background: transparent;
  font: 0.75rem/1.65 var(--mono);
}

.copy-code {
  position: absolute;
  top: 8px;
  right: 8px;
  padding: 5px 8px;
  color: #11130f;
  background: var(--signal);
  border: 0;
  font: 0.55rem var(--mono);
  cursor: pointer;
}

.prose table {
  width: 100%;
  margin: 2rem 0;
  border-collapse: collapse;
  background: rgba(251, 249, 242, 0.65);
  font-size: 0.9rem;
  line-height: 1.45;
}

.prose th,
.prose td {
  padding: 12px 13px;
  text-align: left;
  vertical-align: top;
  border: 1px solid var(--line);
}

.prose th {
  color: #f6f5ed;
  background: var(--ink);
  font: 0.65rem var(--mono);
  letter-spacing: 0.03em;
}

.prose hr { margin: 3rem 0; border: 0; border-top: 1px solid var(--line); }

.page-turns {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-top: 72px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.page-turn {
  display: flex;
  min-height: 115px;
  flex-direction: column;
  justify-content: flex-end;
  padding: 18px;
  color: #f5f3e9;
  background: var(--ink);
  text-decoration: none;
  transition: transform 140ms ease, background 140ms ease;
}

.page-turn:hover { transform: translateY(-3px); background: #292b26; }
.page-turn.next { text-align: right; }
.page-turn.next:only-child { grid-column: 2; }

.page-turn small {
  color: var(--signal);
  font: 0.58rem var(--mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.page-turn strong { font-size: 1.25rem; line-height: 1.1; }

.book-footer {
  display: flex;
  justify-content: space-between;
  margin-top: 58px;
  padding-top: 16px;
  color: var(--ink-soft);
  border-top: 1px solid var(--line);
  font: 0.62rem var(--mono);
}

.book-footer a { text-decoration: none; }
.book-footer a:hover { color: var(--oxide); }

@media (max-width: 980px) {
  :root { --rail-width: min(88vw, 340px); }

  .topbar { grid-template-columns: 58px 1fr auto; }
  .menu-button {
    align-self: stretch;
    display: grid;
    place-content: center;
    gap: 6px;
    border-right: 1px solid rgba(255,255,255,.12);
    cursor: pointer;
  }
  .menu-button span { width: 19px; height: 1px; background: currentColor; }
  .wordmark { border: 0; padding: 0 17px; }
  .topbar-meta { display: none; }
  .portfolio-link { padding: 0 16px; }

  .sidebar {
    transform: translateX(-100%);
    transition: transform 200ms ease;
  }
  .nav-open .sidebar { transform: translateX(0); }
  .nav-scrim {
    position: fixed;
    inset: var(--topbar-height) 0 0;
    z-index: 30;
    display: block;
    visibility: hidden;
    opacity: 0;
    border: 0;
    background: rgba(13, 14, 12, .64);
    transition: opacity 200ms ease, visibility 200ms ease;
  }
  .nav-open .nav-scrim { visibility: visible; opacity: 1; }
  .reading-pane { margin-left: 0; }
}

@media (max-width: 680px) {
  body { font-size: 17px; }
  .portfolio-link { font-size: 0; }
  .portfolio-link::after { content: "HOME ↗"; font-size: 0.68rem; }
  .content-shell { width: min(100% - 34px, 850px); padding-top: 42px; }
  .page-coordinate { margin-bottom: 38px; }
  .briefing-strip { grid-template-columns: 1fr; }
  .briefing-strip span { border-right: 0; border-bottom: 1px solid rgba(255,255,255,.14); }
  .prose > h1:first-child { font-size: clamp(3rem, 16vw, 5rem); }
  .prose h2 { margin-top: 3.8rem; }
  .prose table { display: block; overflow-x: auto; font-size: 0.8rem; }
  .prose pre { margin-inline: -8px; padding: 20px 18px; }
  .page-turns { grid-template-columns: 1fr; }
  .page-turn.next:only-child { grid-column: 1; }
  .book-footer { flex-direction: column; gap: 8px; }
}

@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; transition: none !important; }
}