/* ===========================================================================
   Finding Mind — web edition
   Palette sampled from the hero panel (k-means over the artwork), not invented.
   One type family, Source Serif 4, using its optical-size axis for display,
   text and margin sizes. Mono only where the book itself is mono.
   =========================================================================== */

:root{
  --lead:#14100a;          /* the leading between panes; hero ground */
  --lead-2:#1e180f;
  --vellum:#f3ecd8;        /* the robes; reading ground */
  --vellum-2:#eae1c8;
  --ink:#241c11;
  --ink-2:#5a4c36;
  --ink-3:#8a7a5e;
  --rule:#d8ceb2;
  --gold:#8a6516;          /* haloes */
  --gold-lit:#b98d2f;
  --green:#3d6b4a;         /* the serpent */
  --apple:#9c130e;         /* the one red: reserved for what is unproved */
  --measure:34rem;

  --f: "Source Serif 4","Iowan Old Style",Palatino,Georgia,serif;
  --m: "IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
}

*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0; background:var(--vellum); color:var(--ink);
  font-family:var(--f); font-optical-sizing:auto;
  font-size:20px; line-height:1.6; font-weight:380;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;height:auto}
a{color:inherit;text-decoration:underline;text-decoration-thickness:.5px;
  text-underline-offset:.2em;text-decoration-color:var(--rule)}
a:hover{text-decoration-color:var(--gold-lit)}
:focus-visible{outline:2px solid var(--gold-lit);outline-offset:3px;border-radius:1px}
.skip{position:absolute;left:-9999px}
.skip:focus{left:1rem;top:1rem;z-index:99;background:var(--vellum);padding:.6rem 1rem;
  border:1px solid var(--ink)}
.col{max-width:var(--measure);margin-inline:auto}

/* ===================== HOME ============================================== */

body.home{background:var(--lead);color:var(--vellum)}
body.home a{text-decoration-color:#4a3f2c}
body.home a:hover{text-decoration-color:var(--gold-lit)}

.hero{
  display:grid;grid-template-columns:minmax(0,1fr) minmax(0,26rem);
  gap:clamp(2rem,5vw,5rem);align-items:center;
  max-width:76rem;margin:0 auto;padding:clamp(1.5rem,4vh,3.5rem) clamp(1.2rem,4vw,3rem) clamp(3rem,8vh,6rem);
}
.hero-art{position:relative;justify-self:end;width:100%}
.hero-art img{
  display:block;width:100%;
  /* the panel is lit from behind, as glass is */
  box-shadow:0 0 0 1px #2b2415, 0 40px 90px -30px #000, 0 0 140px -40px #d9b25e;
}
.hero-type h1{
  font-size:clamp(3.2rem,7vw,5.4rem);line-height:.9;margin:0;
  font-weight:400;letter-spacing:-.02em;font-variation-settings:"opsz" 60;
}
.hero-type .sub{
  margin:1rem 0 0;font-size:1.24rem;font-style:italic;color:#cbbf9f;
  max-width:22ch;line-height:1.35;
}
.hero-type .byline{margin:1.6rem 0 0;font-size:1.02rem;color:#e6dcc0}
.actions{margin:2.2rem 0 0;display:flex;gap:.9rem;flex-wrap:wrap}
.go,.alt{
  display:inline-block;padding:.72rem 1.5rem;text-decoration:none;font-size:1rem;
  border:1px solid var(--gold);
}
.go{background:var(--gold-lit);color:#17120a;border-color:var(--gold-lit)}
.go:hover{background:#d3a742}
.alt{color:#e6dcc0}
.alt:hover{background:#211a10}
.hero-type .meta{margin:1.5rem 0 0;font-size:.9rem;color:#8d8265}

.argument{background:var(--vellum);color:var(--ink);padding:clamp(4rem,10vh,7rem) 1.4rem}
.argument .lede{font-size:1.3rem;line-height:1.45}
.argument .turn{
  font-size:1.5rem;font-style:italic;margin:2rem 0;padding-left:1.1rem;
  border-left:3px solid var(--apple);
}
.notation{
  display:grid;grid-template-columns:auto 1fr;gap:.35rem 1.1rem;align-items:baseline;
  margin:2rem 0;padding:1.1rem 0;border-top:1px solid var(--rule);border-bottom:1px solid var(--rule);
  font-size:.98rem;
}
.notation b{font-family:var(--m);font-weight:500;color:var(--green)}
.notation span{color:var(--ink-2)}

.acts{background:var(--vellum);color:var(--ink);padding:0 1.4rem clamp(4rem,10vh,7rem)}
.acts h2{font-size:1.9rem;font-weight:400;margin:0 0 .6rem}
.acts>ol{list-style:none;padding:0;margin:2.5rem auto 0;max-width:52rem;
  border-top:1px solid var(--rule)}
.acts>ol li{border-bottom:1px solid var(--rule);padding:1.6rem 0}
.acts h3{margin:0;font-size:1.4rem;font-weight:400}
.acts h3 a{text-decoration:none}
.acts h3 a:hover{text-decoration:underline;text-decoration-color:var(--gold-lit)}
.acts li p{margin:.4rem 0 0;color:var(--ink-2);max-width:46ch}
.acts .parts{font-size:.88rem;color:var(--ink-3);max-width:56ch}

.apparatus{background:var(--vellum-2);color:var(--ink);padding:clamp(4rem,10vh,7rem) 1.4rem}
.apparatus h2{font-size:1.9rem;font-weight:400;margin:0 0 .8rem;max-width:20ch}
.feat{list-style:none;padding:0;margin:2.6rem auto 0;max-width:60rem;
  display:grid;grid-template-columns:repeat(auto-fit,minmax(15rem,1fr));gap:2rem}
.feat h3{margin:0 0 .4rem;font-size:1.1rem;font-weight:600}
.feat p{margin:0;color:var(--ink-2);font-size:.98rem}

.elsewhere{background:var(--vellum);color:var(--ink);padding:clamp(3.5rem,8vh,6rem) 1.4rem}
.elsewhere h2{font-size:1.9rem;font-weight:400;margin:0 0 1.5rem}
.cols{max-width:52rem;margin:0 auto;display:grid;gap:2.5rem;
  grid-template-columns:repeat(auto-fit,minmax(16rem,1fr))}
.cols h3{font-size:1rem;font-weight:600;margin:0 0 .7rem}
.links{list-style:none;padding:0;margin:0}
.links li{border-top:1px solid var(--rule);padding:.7rem 0}
.links li:last-child{border-bottom:1px solid var(--rule)}
.foot{background:var(--vellum);color:var(--ink-2);padding:0 1.4rem 4rem;font-size:.95rem}

/* ===================== READER ============================================ */

body.readpage{background:var(--vellum)}
.reader{
  display:grid;
  grid-template-columns:16rem minmax(0,1fr) 17rem;
  align-items:start;
  max-width:88rem;margin:0 auto;
}
.rail{position:sticky;top:0;height:100vh;overflow:auto;border-right:1px solid var(--rule);
  padding:1.6rem 1rem 4rem;font-size:.86rem;line-height:1.35;
  scrollbar-width:thin}
.rail-home{display:block;font-size:1.05rem;text-decoration:none;margin-bottom:1.4rem;
  padding-bottom:.9rem;border-bottom:1px solid var(--rule)}
.rail-act{font-size:.78rem;letter-spacing:.06em;font-weight:600;margin:1.8rem 0 .5rem;
  color:var(--gold);font-variant-caps:small-caps}
.rail-part{font-size:.8rem;font-weight:400;font-style:italic;color:var(--ink-3);
  margin:1rem 0 .35rem;line-height:1.25}
.rail-ch{display:grid;grid-template-columns:1.7rem 1fr;gap:.3rem;padding:.24rem 0;
  text-decoration:none;color:var(--ink-2)}
.rail-ch:hover{color:var(--ink)}
.rail-ch .rn{color:var(--ink-3);font-variant-numeric:tabular-nums;font-size:.8rem}
.rail-ch[aria-current]{color:var(--ink);font-weight:600}
.rail-ch[aria-current] .rn{color:var(--apple)}

.text{padding:clamp(2rem,6vh,4.5rem) clamp(1.2rem,4vw,3.4rem) 6rem;max-width:44rem}
.chead{margin:0 0 2.6rem}
.kicker{margin:0 0 .5rem;font-size:.85rem;color:var(--apple);font-variant-caps:small-caps;
  letter-spacing:.05em}
.chead h1{font-size:clamp(2rem,4.2vw,2.9rem);font-weight:400;line-height:1.08;margin:0;
  letter-spacing:-.015em;font-variation-settings:"opsz" 44;text-wrap:balance}
.text p{margin:0 0 1.05em;max-width:36rem}
.text h2,.text h3,.text h4,.text h5{font-weight:600;line-height:1.2;text-wrap:balance;
  margin:2.4em 0 .7em;max-width:32rem}
.text h2{font-size:1.5rem;font-weight:400;border-top:1px solid var(--rule);padding-top:1.4rem}
.text h3{font-size:1.16rem}
.text h4,.text h5{font-size:1rem}
.secnum{color:var(--ink-3);font-variant-numeric:tabular-nums;margin-right:.5em;
  font-size:.85em}
.text ul,.text ol{max-width:34rem;padding-left:1.4rem}
.text li{margin:0 0 .5em}
.text dl{max-width:34rem}
.text dt{font-weight:600;margin-top:.8em}
.text dd{margin:0 0 .5em 1.2rem}
em{font-style:italic}
.sc{font-variant-caps:small-caps}
code{font-family:var(--m);font-size:.86em;background:var(--vellum-2);padding:.05em .28em;
  border-radius:2px}
pre.code{font-family:var(--m);font-size:.8rem;line-height:1.5;background:var(--lead);
  color:#e2d9bf;padding:1.1rem 1.2rem;overflow:auto;max-width:38rem;
  border-left:3px solid var(--green)}
pre.code code{background:none;padding:0;color:inherit}

/* --- numbered results: the color says what kind of claim it is ----------- */
.thm{
  margin:1.8rem 0;padding:1rem 0 1rem 1.2rem;max-width:37rem;
  border-left:3px solid var(--ink-3);background:linear-gradient(90deg,rgba(0,0,0,.028),transparent 60%);
}
.thm>header{font-size:.94rem;margin-bottom:.5rem;display:flex;gap:.5rem;align-items:baseline}
.thm-kind{font-weight:700;letter-spacing:.01em}
.thm-name{font-style:italic;color:var(--ink-2)}
.thm p{margin:0 0 .7em}
.thm p:last-child{margin-bottom:0}
.permalink{margin-left:auto;opacity:0;text-decoration:none;color:var(--ink-3)}
.thm:hover .permalink,.permalink:focus{opacity:1}

.thm-definition,.thm-construction{border-left-color:var(--gold-lit)}
.thm-definition .thm-kind,.thm-construction .thm-kind{color:var(--gold)}
.thm-theorem,.thm-proposition,.thm-lemma,.thm-corollary,.thm-principle{
  border-left-color:var(--green)}
.thm-theorem .thm-kind,.thm-proposition .thm-kind,.thm-lemma .thm-kind,
.thm-corollary .thm-kind,.thm-principle .thm-kind{color:var(--green)}
.thm-conjecture,.thm-question,.thm-requirement,.thm-condition{border-left-color:var(--apple)}
.thm-conjecture .thm-kind,.thm-question .thm-kind,.thm-requirement .thm-kind,
.thm-condition .thm-kind{color:var(--apple)}
.thm-remark,.thm-observation,.thm-example,.thm-nonexample{
  border-left-color:var(--rule);font-size:.95rem}
.thm-remark .thm-kind,.thm-observation .thm-kind,.thm-example .thm-kind{color:var(--ink-2)}

.proof{margin:1.4rem 0;max-width:37rem;font-size:.96rem;color:var(--ink-2)}
.proof>header{font-style:italic;font-weight:400;color:var(--ink);margin-bottom:.3rem}
.proof>*:last-child::after{content:" \25a1";color:var(--ink-3)}

/* --- cross references --------------------------------------------------- */
.xref{
  text-decoration:none;border-bottom:1px solid var(--gold-lit);
  color:var(--gold);font-variant-numeric:tabular-nums;cursor:pointer;
}
.xref:hover{background:rgba(185,141,47,.14)}
.cite{
  text-decoration:none;color:var(--green);font-size:.82em;vertical-align:.25em;
  font-variant-numeric:tabular-nums;border-bottom:1px solid rgba(61,107,74,.4);
}
.xref-dead{color:var(--ink-3);border-bottom:1px dotted var(--ink-3)}

/* --- margin rail --------------------------------------------------------- */
.margin{position:sticky;top:0;height:100vh;overflow:auto;padding:clamp(2rem,6vh,4.5rem) 1.1rem 4rem;
  font-size:.84rem;line-height:1.45;color:var(--ink-2);border-left:1px solid var(--rule)}
.margin:empty::before{content:"References you hover open here.";color:var(--ink-3);
  font-style:italic;display:block;max-width:14rem}
.mcard{border-left:2px solid var(--gold-lit);padding:.5rem 0 .6rem .7rem;margin:0 0 1rem;
  animation:fade .18s ease}
.mcard h4{margin:0 0 .3rem;font-size:.8rem;font-weight:700;color:var(--gold)}
.mcard .mname{font-style:italic;font-weight:400;color:var(--ink-2)}
.mcard p{margin:0 0 .4em}
.mcard .go{all:unset;color:var(--ink-3);font-size:.76rem;cursor:pointer;text-decoration:underline}
.mcard .katex{font-size:.95em}
@keyframes fade{from{opacity:0;transform:translateY(3px)}to{opacity:1;transform:none}}

/* --- figures, tables, floats -------------------------------------------- */
figure{margin:2rem 0;max-width:38rem}
figure.tikz img{display:block;margin:0 auto;max-width:100%}
figcaption{font-size:.85rem;color:var(--ink-2);margin-top:.7rem;max-width:34rem}
.fignum{font-weight:700;color:var(--ink)}
.tablewrap{overflow-x:auto;margin:1.6rem 0;max-width:38rem}
table{border-collapse:collapse;font-size:.86rem;width:100%}
th,td{text-align:left;padding:.45rem .8rem .45rem 0;vertical-align:top;
  border-bottom:1px solid var(--rule)}
th{font-weight:700;border-bottom:1.5px solid var(--ink-3)}
.tikz-missing{color:var(--ink-3);font-style:italic;margin:1.5rem 0}
.math-d{display:block;overflow-x:auto;overflow-y:hidden;margin:1.2rem 0;max-width:38rem}
.pullquote{margin:1.6rem 0 1.6rem 1.2rem;color:var(--ink-2);max-width:34rem;
  border-left:2px solid var(--rule);padding-left:1rem}
.centered{text-align:center}
.frame{border:1px solid var(--rule);padding:1rem 1.2rem;margin:1.6rem 0;max-width:37rem;
  background:var(--vellum-2)}
.epigraph{margin:0 0 2.4rem;padding:0;font-style:italic;color:var(--ink-2);max-width:30rem}
.epigraph cite{display:block;font-style:normal;font-size:.85rem;margin-top:.4rem;
  color:var(--ink-3)}
.asterism{text-align:center;color:var(--ink-3);margin:2rem 0;font-size:1.2rem}
.qline{margin:0;font-style:italic}
.footnotes{margin-top:4rem;border-top:1px solid var(--rule);padding-top:1.2rem;font-size:.88rem;
  color:var(--ink-2);max-width:36rem}
.footnotes h2{font-size:.9rem;font-weight:700;border:0;padding:0;margin:0 0 .6rem}
sup.fn a{text-decoration:none;color:var(--apple)}

/* --- interlude: the literary voice gets a different setting -------------- */
.text.interlude{max-width:38rem}
.text.interlude p{max-width:31rem;font-size:1.04rem;line-height:1.72}
.text.interlude .chead h1{font-style:italic;font-weight:300}

.pager{display:flex;justify-content:space-between;gap:2rem;margin-top:5rem;
  border-top:1px solid var(--rule);padding-top:1.4rem;font-size:.95rem}
.pager a{text-decoration:none;max-width:16rem}
.pager a:hover{text-decoration:underline}
.pager span{display:block;font-size:.78rem;color:var(--ink-3)}
.pager .next{text-align:right;margin-left:auto}

.railtoggle{display:none}

/* ===================== PLAIN PAGES ======================================= */
body.plainpage .page{max-width:52rem;margin:0 auto;padding:clamp(2.5rem,7vh,5rem) 1.4rem 6rem}
.phead{margin-bottom:2.5rem}
.back{font-size:.9rem;text-decoration:none;color:var(--ink-2)}
.phead h1{font-size:clamp(2rem,4.5vw,2.8rem);font-weight:400;margin:.8rem 0 0;
  font-variation-settings:"opsz" 44}
.phead .lede{color:var(--ink-2);max-width:40ch;margin-top:.8rem}

.toc-act{font-size:1.5rem;font-weight:400;margin:3rem 0 .3rem;color:var(--gold)}
.toc-part{font-size:1rem;font-weight:400;font-style:italic;color:var(--ink-2);
  margin:1.8rem 0 .5rem;border-bottom:1px solid var(--rule);padding-bottom:.4rem}
.toc-part .pn{font-style:normal;color:var(--ink-3);margin-right:.7rem;font-size:.85rem}
.toc-ch{display:grid;grid-template-columns:2.4rem 1fr auto;gap:1rem;padding:.42rem 0;
  text-decoration:none;align-items:baseline;border-bottom:1px solid rgba(216,206,178,.5)}
.toc-ch:hover{background:var(--vellum-2)}
.toc-ch .cn{color:var(--ink-3);font-variant-numeric:tabular-nums;text-align:right}
.toc-ch .cw{color:var(--ink-3);font-size:.8rem;font-variant-numeric:tabular-nums}
.toc-int .ct{font-style:italic}

.filters{margin-top:1.6rem}
#q{font:inherit;font-size:1rem;padding:.6rem .8rem;width:100%;max-width:26rem;
  background:var(--vellum);border:1px solid var(--rule);color:var(--ink)}
.chips{display:flex;flex-wrap:wrap;gap:.4rem;margin-top:.9rem}
.chips button{font:inherit;font-size:.8rem;padding:.25rem .7rem;cursor:pointer;
  background:none;border:1px solid var(--rule);color:var(--ink-2);border-radius:99px}
.chips button[aria-pressed="true"]{background:var(--ink);color:var(--vellum);
  border-color:var(--ink)}
.ledger{margin-top:1.6rem}
.lrow{display:grid;grid-template-columns:7.5rem 3.5rem 1fr;gap:.8rem;padding:.4rem 0;
  text-decoration:none;border-bottom:1px solid rgba(216,206,178,.6);font-size:.92rem}
.lrow:hover{background:var(--vellum-2)}
.lk{color:var(--ink-3);font-size:.82rem}
.ln{font-variant-numeric:tabular-nums;color:var(--gold)}
.empty{color:var(--ink-3);font-style:italic}
.bib{padding-left:0;list-style:none;font-size:.92rem}
.bib li{display:grid;grid-template-columns:2.6rem 1fr;gap:.8rem;padding:.55rem 0;
  border-bottom:1px solid rgba(216,206,178,.6)}
.bn{color:var(--ink-3);font-variant-numeric:tabular-nums;text-align:right}

/* ===================== RESPONSIVE ======================================== */
@media (max-width:1180px){
  .reader{grid-template-columns:15rem minmax(0,1fr)}
  .margin{display:none}
}
@media (max-width:900px){
  body{font-size:19px}
  .hero{grid-template-columns:1fr;padding-top:2rem}
  .hero-art{justify-self:center;max-width:30rem}
  .hero-type{text-align:left}
  .reader{grid-template-columns:minmax(0,1fr)}
  .rail{position:fixed;inset:0 auto 0 0;width:19rem;z-index:40;background:var(--vellum);
    transform:translateX(-100%);transition:transform .22s ease;box-shadow:0 0 60px rgba(0,0,0,.25)}
  body.rail-open .rail{transform:none}
  .railtoggle{display:block;position:fixed;left:.8rem;bottom:.8rem;z-index:50;
    font:inherit;font-size:.9rem;padding:.55rem 1.1rem;background:var(--ink);
    color:var(--vellum);border:0;cursor:pointer}
  .text{padding-bottom:5rem}
  .lrow{grid-template-columns:1fr;gap:.1rem}
  .lk{font-size:.75rem}
}
@media (prefers-reduced-motion:reduce){
  *{animation:none!important;transition:none!important}
}
@media print{
  .rail,.margin,.railtoggle,.pager{display:none}
  body{background:#fff;font-size:11pt}
  .reader{display:block}
}

/* the home link stays put when the rail auto-scrolls to the current chapter */
.rail{padding-top:0}
.rail-home{position:sticky;top:0;z-index:2;background:var(--vellum);
  margin:0 0 .6rem;padding:1.4rem 0 .8rem;border-bottom:1px solid var(--rule);
  box-shadow:0 6px 10px -8px rgba(20,16,10,.35)}

/* ledger: the red marks what the book has not proved */
.owedline{display:flex;gap:1rem;align-items:baseline;margin:.9rem 0 0;font-size:.88rem}
#owed{font:inherit;font-size:.88rem;padding:.3rem .8rem;cursor:pointer;background:none;
  border:1px solid var(--apple);color:var(--apple);border-radius:99px}
#owed[aria-pressed="true"]{background:var(--apple);color:var(--vellum)}
#count{color:var(--ink-3);font-variant-numeric:tabular-nums}
.chips button.owedchip{border-color:rgba(156,19,14,.45);color:var(--apple)}
.chips button.owedchip[aria-pressed="true"]{background:var(--apple);border-color:var(--apple);
  color:var(--vellum)}
.lrow.owed .ln{color:var(--apple)}
.lrow.owed .lk{color:var(--apple)}
.unnamed{color:var(--ink-3);font-style:italic}