/* ================= themes ================= */
:root {
  --ink: #0d0c0a;
  --ink-2: #12100d;
  --bone: #ece7dd;
  --muted: #a39d8f;
  --faint: #85806f;
  --hair: rgba(236,231,221,0.14);
  --hair-soft: rgba(236,231,221,0.07);
  --edge: rgba(236,231,221,0.30);
  --sage: #9db89a;
  --coral: #e8927c;
  --ice: #a8c5d6;
  --sand: #d6c08f;
  --glass: rgba(13,12,10,0.5);
  --serif: 'Fraunces', Georgia, serif;
  --mono: 'IBM Plex Mono', ui-monospace, monospace;

  /* type scale — one ladder, used everywhere instead of ad-hoc px values */
  --fs-lead: 20px;
  --fs-body: 19px;
  --fs-body-2: 17px;
  --fs-note: 15px;
  --fs-mono-lg: 14px;
  --fs-mono: 12px;
  --fs-mono-sm: 11px;
  /* code blocks — one size, so the terminal and the contract card match */
  --fs-code: clamp(11.5px, 2.9vw, 13.5px);

  color-scheme: dark;
}
[data-theme="light"] {
  --ink: #f3eee3;
  --ink-2: #ebe5d6;
  --bone: #241f17;
  --muted: #514a3d;
  --faint: #655e4c;
  --hair: rgba(36,31,23,0.18);
  --hair-soft: rgba(36,31,23,0.10);
  --edge: rgba(36,31,23,0.42);
  --sage: #4b6345;
  --coral: #9a4527;
  --ice: #426074;
  --sand: #715c2d;
  --glass: rgba(243,238,227,0.62);

  color-scheme: light;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body {
  background: var(--ink);
  color: var(--bone);
  font-family: var(--serif);
  font-size: var(--fs-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  transition: background .5s ease, color .5s ease;
}
::selection { background: rgba(232,146,124,0.32); color: var(--bone); }
[data-theme="light"] ::selection { background: rgba(154,69,39,0.22); color: var(--bone); }
/* #boot and .term-frame are always dark — they must keep light selected text
   in both themes, or the selection turns dark-on-dark in light mode */
#boot ::selection, .term-frame ::selection { background: rgba(232,146,124,0.32); color: #ece7dd; }
.mono { font-family: var(--mono); }
b { font-weight: 600; }
main { position: relative; z-index: 1; }

/* every interactive control gets the same, always-visible focus ring.
   no border-radius here — the outline already follows each control's own
   corner radius, and setting one squares off the pill buttons on focus. */
:focus-visible {
  outline: 2px solid var(--sage);
  outline-offset: 3px;
}
.sr-only {
  position: absolute; width: 1px; height: 1px; overflow: hidden;
  clip: rect(0 0 0 0); clip-path: inset(50%); white-space: nowrap;
}

/* ================= plankton layer ================= */
#plankton {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
}

/* ================= boot overlay (always dark — it's a screen) ============ */
#boot {
  position: fixed; inset: 0; z-index: 1000;
  background: #080706;
  display: flex; flex-direction: column; justify-content: center;
  padding: 72px max(24px, calc(50vw - 330px));
  cursor: pointer;
  overflow-y: auto;
  transition: opacity .7s ease;
}
#boot.off { opacity: 0; pointer-events: none; }
html:not(.js) #boot, html.booted #boot { display: none; }
#boot-log {
  font-family: var(--mono); font-size: clamp(11px, 3vw, 13px); line-height: 1.9;
  color: #8f897c; white-space: pre-wrap; word-break: break-word;
}
#boot-log .ok { color: #9db89a; }
#boot-log .hl { color: #ece7dd; }
#boot-log .warn { color: #e8927c; }
#boot-skip {
  /* fixed, not absolute: #boot scrolls its log, and an absolute child
     scrolls away with it on short viewports */
  position: fixed; bottom: 28px; left: 50%; transform: translateX(-50%);
  font-family: var(--mono); font-size: var(--fs-mono-sm); letter-spacing: .2em;
  color: #807a6d; text-transform: uppercase;
  background: none; border: 0; padding: 8px 14px; cursor: pointer;
}
#boot-skip:hover { color: #ece7dd; }

/* ================= theme toggle ================= */
#theme-btn {
  font-family: var(--mono); font-size: var(--fs-mono-sm); letter-spacing: .14em; text-transform: uppercase;
  color: var(--muted);
  background: transparent;
  border: 1px solid var(--edge); border-radius: 100px;
  padding: 7px 14px; cursor: pointer; flex: none;
  transition: color .25s, border-color .25s;
}
/* without JS the button can never become visible — don't leave an invisible tab stop */
html:not(.js) #theme-btn { display: none; }
#theme-btn:hover { color: var(--bone); border-color: var(--muted); }

/* ================= hero ================= */
#hero {
  position: relative; min-height: 100svh;
  display: flex; align-items: center; justify-content: center;
  text-align: center; overflow: hidden;
}
#hero-canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero-inner { position: relative; z-index: 2; padding: 0 26px; max-width: 880px; }
.kicker {
  font-family: var(--mono); font-size: clamp(10.5px, 2.6vw, var(--fs-mono));
  letter-spacing: clamp(.16em, 1vw, .3em);
  text-transform: uppercase; color: var(--muted); margin-bottom: 34px;
}
h1 {
  font-size: clamp(46px, 7.6vw, 96px);
  font-weight: 300; line-height: 1.06; letter-spacing: -0.015em;
}
h1 em { font-style: italic; font-weight: 300; color: var(--sage); }
.hero-sub {
  margin: 36px auto 0; max-width: 560px;
  font-size: clamp(17px, 4.4vw, var(--fs-lead)); color: var(--muted); line-height: 1.65;
}
.hero-sub b { color: var(--bone); }
.scroll-cue { position: absolute; bottom: 30px; left: 50%; transform: translateX(-50%); z-index: 2; }
.scroll-cue span {
  display: block; width: 1px; height: 56px;
  background: linear-gradient(180deg, transparent, var(--muted));
  animation: cue 2.4s ease-in-out infinite;
}
@keyframes cue { 0%,100% { transform: scaleY(.4); opacity:.3; } 50% { transform: scaleY(1); opacity:.9; } }
/* short/landscape viewports: the cue would sit on top of the hero paragraph */
@media (max-height: 600px) { .scroll-cue { display: none; } }

html.js .hero-inner > * { opacity: 0; transform: translateY(22px); transition: opacity 1.1s ease, transform 1.1s cubic-bezier(.16,1,.3,1); }
html.js.booted .hero-inner > * { opacity: 1; transform: none; }
html.js.booted .hero-inner .kicker { transition-delay: .15s; }
html.js.booted .hero-inner h1 { transition-delay: .3s; }
html.js.booted .hero-inner .hero-sub { transition-delay: .55s; }

/* ================= chapters ================= */
.chapter { padding: clamp(84px, 13vh, 170px) 26px; position: relative; }
.ch-inner { max-width: 1040px; margin: 0 auto; }
.ch-inner.narrow { max-width: 660px; }
.ch-inner.center { text-align: center; }
.ch-no {
  font-family: var(--mono); font-size: var(--fs-mono); letter-spacing: .28em;
  text-transform: uppercase; color: var(--faint); margin-bottom: 26px;
}
h2 {
  font-size: clamp(34px, 4.6vw, 56px);
  font-weight: 300; line-height: 1.12; letter-spacing: -0.012em;
  max-width: 720px;
}
.ch-inner.center h2 { margin: 0 auto; }
.prose {
  margin-top: 28px; font-size: var(--fs-body); color: var(--muted);
  max-width: 620px; line-height: 1.7;
}
.prose + .prose { margin-top: 20px; }
.ch-inner.center .prose { margin-left: auto; margin-right: auto; }
.prose b { color: var(--bone); }
.caption { margin-top: 22px; font-size: var(--fs-note); color: var(--faint); max-width: 620px; line-height: 1.7; }
.ch-inner.center .caption { margin-left: auto; margin-right: auto; }
.caption b { color: var(--muted); }
/* one inline-code treatment: <code> and inline .mono must not look like two things */
.prose code, .caption code, .prose .mono, .caption .mono {
  font-family: var(--mono); font-size: .82em; color: var(--sage);
  overflow-wrap: break-word;
}
.prose code, .caption code {
  border: 1px solid var(--hair); border-radius: 4px; padding: 2px 7px;
}

.spawn-strip {
  max-width: 1040px; margin: 0 auto 34px; padding: 0 0 14px;
  font-family: var(--mono); font-size: var(--fs-mono-sm); letter-spacing: .04em;
  color: var(--faint);
  border-bottom: 1px solid var(--hair);
  min-height: 32px; position: relative;
}
.spawn-strip::after {
  content: ''; position: absolute; left: 0; bottom: -1px; height: 1px; width: 0;
  background: linear-gradient(90deg, var(--sage), transparent);
  transition: width 1.4s cubic-bezier(.16,1,.3,1);
}
.chapter.on .spawn-strip::after { width: 100%; }
.spawn-strip .ok { color: var(--sage); }
/* the strip is the rule above the text column — it must share that column's width */
.chapter:has(.ch-inner.narrow) .spawn-strip { max-width: 660px; }

html.js .ch-inner { opacity: 0; transform: translateY(34px); transition: opacity 1s ease .2s, transform 1s cubic-bezier(.16,1,.3,1) .2s; }
html.js .chapter.on .ch-inner { opacity: 1; transform: none; }

/* ================= numerals ================= */
.numerals {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: clamp(28px, 5vw, 60px); margin-top: 64px;
}
/* below ~640px auto-fit resolves to two columns and strands the third numeral
   alone on a second row — stack them instead */
@media (max-width: 640px) { .numerals { grid-template-columns: 1fr; } }
.nume .n { display: block; font-size: clamp(52px, 7vw, 80px); font-weight: 300; line-height: 1; }
.nume:nth-child(1) .n { color: var(--sage); }
.nume:nth-child(2) .n { color: var(--coral); }
.nume:nth-child(3) .n { color: var(--ice); }
.nume .l {
  display: block; margin-top: 12px;
  font-family: var(--mono); font-size: var(--fs-mono-sm); letter-spacing: .14em;
  text-transform: uppercase; color: var(--faint); line-height: 1.8;
}

/* ================= playground ================= */
.playground-frame {
  margin-top: 48px; position: relative;
  border: 1px solid var(--hair); border-radius: 18px;
  background: var(--ink-2);
  overflow: hidden;
  transition: background .5s ease;
}
#play-canvas { display: block; width: 100%; height: clamp(420px, 60vh, 600px); }
#play-canvas:focus-visible { outline-offset: -3px; }
.play-stats {
  padding: 14px 24px;
  font-family: var(--mono); font-size: var(--fs-mono); color: var(--faint);
  display: flex; gap: 6px 12px; justify-content: center; flex-wrap: wrap;
  border-top: 1px solid var(--hair);
  background: var(--glass); backdrop-filter: blur(6px);
}
.play-stats b { color: var(--bone); font-weight: 500; }
.play-stats b.ok { color: var(--sage); }
.play-stats b.bad { color: var(--coral); }
.play-stats .sep { color: var(--faint); opacity: .45; }
.play-hint {
  margin-top: 16px; font-family: var(--mono); font-size: var(--fs-mono-sm);
  letter-spacing: .04em; line-height: 1.8; color: var(--faint);
}
.play-hint b { color: var(--muted); font-weight: 500; }
/* the caption now follows the hint, not the frame — it needs its own gap */
.play-hint + .sr-only + .caption { margin-top: 30px; }

/* ================= anatomy (clickable architecture) ================= */
.arch { display: grid; grid-template-columns: 1.15fr .85fr; gap: 26px; margin-top: 48px; align-items: start; }
@media (max-width: 860px) {
  .arch { grid-template-columns: 1fr; }
  .arch-info { position: static; }
}
.arch-stack { display: flex; flex-direction: column; gap: 10px; }
.arch-row { display: grid; gap: 10px; }
.arch-row.g3 { grid-template-columns: repeat(3, 1fr); }
.arch-row.entry { grid-template-columns: 1fr 2fr; }
.arch-row.entry .arch-flow { align-self: center; }
@media (max-width: 560px) {
  /* 1fr 2fr leaves the arkctl node ~90px wide on a phone — stack instead */
  .arch-row.g3, .arch-row.entry { grid-template-columns: 1fr; }
  .arch-row.entry .arch-flow { text-align: left; }
}
.arch-label {
  font-family: var(--mono); font-size: var(--fs-mono-sm); letter-spacing: .22em;
  text-transform: uppercase; color: var(--faint); margin-top: 8px;
}
.arch-flow { text-align: center; font-family: var(--mono); font-size: var(--fs-mono-sm); color: var(--faint); padding: 2px 0; }
.node {
  /* an operable control needs a perceivable boundary — --hair is decorative only */
  border: 1px solid var(--edge); border-radius: 12px; background: var(--ink-2);
  padding: 14px; font-family: var(--mono); font-size: var(--fs-mono); color: var(--bone);
  cursor: pointer; text-align: left;
  transition: border-color .25s, box-shadow .25s, transform .25s, background .5s ease;
}
.node small { display: block; margin-top: 5px; font-size: var(--fs-mono-sm); color: var(--faint); line-height: 1.5; }
.node:hover { border-color: var(--muted); transform: translateY(-1px); }
/* selection was a 1px hue change against a 1px hue change — make it readable */
.node.sel { border-color: var(--sage); box-shadow: inset 0 0 0 1px var(--sage); }
.node.sel small { color: var(--muted); }
.arch-info {
  border: 1px solid var(--hair); border-radius: 14px; background: var(--ink-2);
  padding: 22px 24px; position: sticky; top: 74px; transition: background .5s ease;
}
.arch-info h3 { font-family: var(--mono); font-size: var(--fs-mono); letter-spacing: .14em; color: var(--sage); font-weight: 500; margin-bottom: 12px; }
.arch-info p { font-size: var(--fs-note); color: var(--muted); line-height: 1.65; }
.arch-info p + p { margin-top: 12px; }
.arch-info .mono { font-size: .82em; color: var(--sage); }

/* ================= contract card ================= */
.contract {
  margin-top: 48px; border: 1px solid var(--hair); border-radius: 14px;
  overflow: hidden; background: var(--ink-2); transition: background .5s ease;
}
.contract .ct-head { padding: 13px 26px; font-family: var(--mono); font-size: var(--fs-mono); color: var(--faint); border-bottom: 1px solid var(--hair); }
.contract pre {
  padding: 24px 26px; font-family: var(--mono);
  font-size: var(--fs-code); line-height: 1.9; color: var(--muted);
  white-space: pre-wrap; overflow-wrap: break-word;
}
.contract .dim { color: var(--faint); }
.contract .m { color: var(--sage); }
.contract .r { color: var(--coral); }

/* ================= terminal (always dark — it's a screen) ============ */
.term-frame {
  /* a hairline tuned for the dark screen it borders, not for the page theme */
  margin-top: 48px; border: 1px solid rgba(236,231,221,0.14); border-radius: 14px;
  overflow: hidden; background: #0a0908;
}
/* the code figures share one measure so their edges line up chapter to chapter */
.contract, .term-frame { max-width: 780px; }
.term-head {
  display: flex; align-items: center; gap: 7px; flex-wrap: wrap;
  padding: 13px 24px; font-family: var(--mono); font-size: var(--fs-mono); color: #8a8477;
  border-bottom: 1px solid rgba(236,231,221,0.1);
}
.term-head .td { width: 9px; height: 9px; border-radius: 50%; flex: none; }
.term-head .td:nth-child(1) { background: rgba(232,146,124,.5); }
.term-head .td:nth-child(2) { background: rgba(214,192,143,.5); }
.term-head .td:nth-child(3) { background: rgba(157,184,154,.5); }
.term-head .term-title { margin-left: 10px; overflow-wrap: break-word; }
.term-body {
  padding: 24px 24px 28px; font-family: var(--mono);
  font-size: var(--fs-code); line-height: 1.85;
  min-height: 300px; white-space: pre-wrap; word-break: break-word;
  color: #a39d8f;
}
.term-body .p { color: #9db89a; }
.term-body .dim { color: #7f7a6d; }
.term-body .route { color: #d6c08f; }
.term-body .ans { color: #ece7dd; font-style: italic; font-family: var(--serif); font-size: var(--fs-body-2); line-height: 1.7; }
.term-body .deny { color: #e8927c; }
.tcursor { display: inline-block; width: 7px; height: 15px; background: #9db89a; vertical-align: -2px; animation: blink 1s step-start infinite; }
@keyframes blink { 50% { opacity: 0; } }

/* ================= chronicle ================= */
.chron { list-style: none; margin-top: 54px; }
.chron li {
  display: grid; grid-template-columns: 84px 1fr; gap: 22px;
  padding: 16px 0; align-items: baseline;
  border-bottom: 1px solid var(--hair-soft);
  font-size: var(--fs-body-2); color: var(--muted);
}
.chron li b { color: var(--bone); font-weight: 500; }
.chron .v { font-family: var(--mono); font-size: var(--fs-mono); color: var(--faint); }
.chron li.done .v { color: var(--sage); }
.chron .dot {
  display: inline-block; width: 6px; height: 6px; border-radius: 50%;
  background: var(--sage); margin-left: 8px; vertical-align: .18em; flex: none;
}
.chron li.now > span:last-child::after { content: ' — in progress'; font-style: italic; color: var(--faint); font-size: .86em; }

/* ================= coda ================= */
#coda { text-align: center; padding: 22vh 26px 18vh; }
.coda-line { font-size: clamp(38px, 5.6vw, 64px); font-weight: 300; line-height: 1.15; letter-spacing: -0.012em; }
.coda-line em { color: var(--sage); }
.colophon { margin-top: 64px; font-family: var(--mono); font-size: var(--fs-mono-sm); letter-spacing: .26em; text-transform: uppercase; color: var(--faint); }

/* ================= motion prefs / responsive ================= */
@media (prefers-reduced-motion: reduce) {
  html.js .ch-inner, html.js .hero-inner > * { opacity: 1 !important; transform: none !important; transition: none !important; }
  .scroll-cue { animation: none; }
  #boot { display: none; }
}
@media (max-width: 640px) {
  .chapter { padding: 12vh 20px; }
  .hero-inner { padding: 0 20px; }
  .chron li { grid-template-columns: 62px 1fr; gap: 14px; }
  .numerals { gap: 36px; }
}

/* ================= top nav ================= */
#topnav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 600;
  display: flex; align-items: center; gap: 16px;
  padding: 12px 22px;
  background: var(--glass); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--hair);
  font-family: var(--mono);
}
.nav-brand {
  color: var(--bone); text-decoration: none;
  font-size: var(--fs-mono); letter-spacing: .3em; text-transform: uppercase;
  flex: none;
}
.nav-brand .dot-k { color: var(--coral); }
.nav-tabs {
  display: flex; gap: 2px; margin-left: auto;
  overflow-x: auto; scrollbar-width: none;
}
.nav-tabs::-webkit-scrollbar { display: none; }
.nav-tabs a {
  color: var(--faint); text-decoration: none; white-space: nowrap;
  font-size: var(--fs-mono-sm); letter-spacing: .1em; text-transform: uppercase;
  padding: 7px 13px; border: 1px solid transparent; border-radius: 100px;
  transition: color .2s, border-color .2s;
}
.nav-tabs a:hover { color: var(--bone); }
.nav-tabs a[aria-current="page"] { color: var(--sage); border-color: var(--sage); }
@media (max-width: 720px) {
  #topnav { padding: 10px 12px; gap: 10px; }
  .nav-brand { letter-spacing: .18em; }
}

/* ================= page head (subpages) ================= */
.page-head { padding: clamp(120px, 18vh, 190px) 26px 0; }
.page-head .ch-inner { max-width: 1040px; margin: 0 auto; }

/* page-head sits outside .chapter — never held at opacity 0 by the reveal rule */
html.js .page-head .ch-inner { opacity: 1; transform: none; }

/* proof tiles on index link out */
a.nume { text-decoration: none; color: inherit; display: block; border-radius: 12px; }
a.nume:hover .l { color: var(--muted); }
.nume .n small { font-size: .38em; font-weight: 300; letter-spacing: 0; }

/* planned rows in the chronicle */
.chron li.plan .v { color: var(--faint); }
.chron li.plan > span:last-child::after { content: ' — planned'; font-style: italic; color: var(--faint); font-size: .86em; }

/* footer nav line */
.colophon a { color: var(--faint); text-decoration: none; }
.colophon a:hover { color: var(--bone); }