:root{
  --paper:#f6f4ee; --band:#efece3; --surface:#fffefb; --panel:#16181c;
  --ink:#1b1a17; --ink2:#3c3a35; --mut:#746f66; --faint:#a49e93; --line:#e4ded2; --line2:#d6cfbf;
  --teal:#0f6b5f; --tealD:#0a544a; --clay:#b1532e; --steel:#3f6a8a;
  --serif:'Newsreader',Georgia,serif; --sans:'Inter',system-ui,sans-serif; --mono:'JetBrains Mono',ui-monospace,monospace;
}

/* shadows (used as utility-style classes) */
.shadow-soft{box-shadow:0 1px 2px rgba(30,25,15,.04),0 8px 26px -16px rgba(30,25,15,.16)}
.shadow-lift{box-shadow:0 2px 6px rgba(30,25,15,.05),0 26px 54px -34px rgba(30,25,15,.30)}

/* element fixes over Tailwind preflight */
body em{font-style:normal;color:var(--clay);font-weight:500}
body strong{color:var(--ink);font-weight:600}

/* typography — standard reading sizes */
.step{font-family:var(--mono);font-size:12px;letter-spacing:.1em;text-transform:uppercase;color:var(--clay);margin:0 0 12px}
.h2{font-family:var(--serif);font-weight:500;font-size:1.55rem;line-height:1.22;color:var(--ink);margin:0 0 16px}
@media(min-width:640px){.h2{font-size:1.85rem}}
.body{font-size:1.0625rem;line-height:1.72;color:var(--ink2);margin:0 0 16px}
.cap{font-size:.9rem;line-height:1.55;color:var(--mut);margin:0}
.tag{font-family:var(--mono);font-size:10.5px;font-weight:500;color:var(--teal);border:1px solid var(--teal);
  border-radius:5px;padding:1px 6px;letter-spacing:.04em;text-transform:uppercase;vertical-align:middle;margin-left:6px}

/* nav */
#nav{backdrop-filter:saturate(1.4) blur(10px);background:rgba(246,244,238,.82);border-bottom:1px solid transparent;transition:border-color .3s}
#nav.solid{border-bottom-color:var(--line)}

/* buttons */
.btn-primary,.btn-ghost{display:inline-block;font-size:14.5px;font-weight:500;padding:10px 18px;border-radius:9px;
  cursor:pointer;transition:.2s;border:1px solid;text-decoration:none}
.btn-primary{background:var(--teal);border-color:var(--teal);color:#fff}
.btn-primary:hover{background:var(--tealD);border-color:var(--tealD);color:#fff;text-decoration:none}
.btn-ghost{background:var(--surface);border-color:var(--line2);color:var(--ink2)}
.btn-ghost:hover{border-color:var(--teal);color:var(--teal);text-decoration:none}
.cheat-btn{font-size:14px;font-weight:500;padding:9px 15px;border-radius:9px;border:1px solid var(--line2);
  background:var(--surface);color:var(--ink2);cursor:pointer;transition:.18s}
.cheat-btn:hover{border-color:var(--teal);color:var(--teal)}
.cheat-btn.active{background:var(--teal);border-color:var(--teal);color:#fff}

/* grouped task tiles */
.taskgroup{margin-bottom:18px}
.taskgroup:last-child{margin-bottom:0}
.grouptitle{display:flex;align-items:center;gap:8px;font-size:13.5px;font-weight:600;color:var(--ink);margin:0 0 9px}
.gdot{width:9px;height:9px;border-radius:50%;display:inline-block;flex:none}
.gcount{font-family:var(--mono);font-size:11px;font-weight:400;color:var(--faint);margin-left:auto}
.tasktiles{display:grid;grid-template-columns:repeat(2,1fr);gap:8px}
@media(min-width:768px){.tasktiles{grid-template-columns:1fr}}
.tile{display:flex;align-items:center;justify-content:space-between;gap:10px;width:100%;text-align:left;background:var(--surface);
  border:1px solid var(--line);border-left:3px solid var(--tc,#ccc);border-radius:9px;padding:9px 12px;cursor:pointer;
  transition:transform .12s,box-shadow .12s,background .12s;box-shadow:0 1px 2px rgba(30,25,15,.04);font-family:inherit}
.tile:hover{background:#fffdf8;box-shadow:0 8px 20px -15px rgba(30,25,15,.3)}
.tile.sel{box-shadow:inset 3px 0 0 var(--tc),0 0 0 1px var(--tc);border-left-color:var(--tc)}
.tname{font-size:13px;color:var(--ink2);font-weight:500;line-height:1.2}
.tval{font-family:var(--serif);font-size:18px;font-weight:500;line-height:1;flex:none}

/* category detail */
.cat{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:22px 24px;box-shadow:var(--bs,0 1px 2px rgba(30,25,15,.04),0 8px 26px -18px rgba(30,25,15,.18))}
.cat-head{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-bottom:12px}
.cat h3{font-family:var(--serif);font-weight:500;font-size:1.3rem;color:var(--ink);margin:0}
.chips{display:flex;gap:7px}
.chip{font-family:var(--mono);font-size:11.5px;padding:3px 9px;border-radius:6px;border:1px solid}
.chip.model{color:var(--clay);border-color:#e3c2b2;background:#fbf0ea}
.chip.solver{color:var(--teal);border-color:#bcdcd4;background:#eef6f4}
.cat-what{font-size:15.5px;color:var(--ink2);line-height:1.6;margin:0 0 16px}
.cat-block{margin:0 0 16px}
.cat-blabel{font-family:var(--mono);font-size:10.5px;text-transform:uppercase;letter-spacing:.07em;color:var(--faint);margin:0 0 6px}
.cat-ex{font-family:var(--mono);font-size:13px;color:var(--ink2);background:var(--band);border:1px solid var(--line);
  border-bottom:0;border-radius:8px 8px 0 0;padding:11px 14px;display:grid;grid-template-columns:1fr auto 1fr;
  gap:5px 12px;align-items:baseline;overflow-x:auto}
.cat-ex .exl{text-align:right;white-space:nowrap}
.cat-ex .exr{text-align:left;white-space:nowrap}
.cat-ex .exa{color:var(--faint)}
.cat-exq{font-family:var(--mono);font-size:13px;color:var(--ink);background:#fbf7ef;border:1px solid var(--line);
  border-radius:0 0 8px 8px;padding:11px 14px;display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.cat-exq .exqlab{font-family:var(--sans);font-size:10px;text-transform:uppercase;letter-spacing:.08em;color:var(--faint)}
.cat-exq .exa{color:var(--faint)}
.cat-exq .ans{color:var(--teal);font-weight:600}
.cat-trace{background:#0e1013;border:1px solid #262a31;color:#cdd3db;font-family:var(--mono);font-size:12.5px;line-height:1.7;
  padding:12px 14px;border-radius:8px;margin:0;white-space:pre-wrap;word-break:break-word}
.cat-trace .hit{color:#ff9b86;font-weight:600;background:rgba(177,83,46,.24);border-radius:3px;padding:0 3px}
.cat-trace .ok{color:#6fd0a0;font-weight:600}
.cat-tnote{font-size:13.5px;color:var(--mut);line-height:1.55;margin:9px 0 0}
.cat-why{font-size:15px;color:var(--ink2);line-height:1.65;margin:0}
.cat-why b{color:var(--ink);font-weight:600}

/* solver-vs-model compare */
.vs{border:1px solid var(--line);border-radius:9px;overflow:hidden}
.vsrow{display:flex;align-items:center;gap:9px;padding:9px 13px;font-family:var(--mono);font-size:13px}
.vsrow+.vsrow{border-top:1px solid var(--line)}
.vsrow.solver{background:#eef6f4}
.vsrow.model.ok{background:#edf5ee}
.vsrow.model.bad{background:#fbf0ea}
.vslab{font-family:var(--sans);font-size:10px;text-transform:uppercase;letter-spacing:.06em;color:var(--mut);width:46px;flex:none}
.vsarrow{color:var(--faint);flex:none}
.vsval{font-weight:600;color:var(--ink);flex:1;min-width:0;word-break:break-word}
.vsrow.solver .vsval{color:var(--teal)}
.vsrow.model.bad .vsval{color:var(--clay)}
.vsmeth{font-family:var(--sans);font-size:11px;color:var(--mut);flex:none;text-align:right;max-width:44%}
.vstag{font-family:var(--sans);font-size:10px;font-weight:700;text-transform:uppercase;letter-spacing:.04em;padding:2px 7px;border-radius:5px;flex:none}
.vstag.ok{background:#d9ede3;color:#0a544a}
.vstag.bad{background:#f3d9cf;color:#8f3a1c}

/* bar chart */
.chart{display:flex;flex-direction:column;gap:10px}
.grouphdr{font-family:var(--mono);font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--faint);margin:14px 0 2px}
.grouphdr:first-child{margin-top:0}
.brow{display:grid;grid-template-columns:minmax(104px,200px) 1fr 48px;align-items:center;gap:13px}
.brow.ref{padding-bottom:10px;margin-bottom:4px;border-bottom:1px dashed var(--line2)}
.blabel{font-size:14px;color:var(--ink2);text-align:right;line-height:1.22}
.brow.ref .blabel{color:var(--teal);font-weight:500}
.blabel small{display:block;font-family:var(--mono);font-size:10.5px;color:var(--faint);margin-top:1px}
.btrack{position:relative;height:24px;background:var(--band);border:1px solid var(--line);border-radius:6px;overflow:hidden}
.bfill{position:absolute;left:0;top:0;bottom:0;width:0;border-radius:5px 0 0 5px;transition:width 1s cubic-bezier(.2,.8,.2,1)}
.in .bfill{width:var(--w)}
.bfill.model{background:linear-gradient(90deg,#b1532e,#cf7148)}
.bfill.solver{background:linear-gradient(90deg,#0f6b5f,#2c9183)}
.bval{font-family:var(--mono);font-size:13px;color:var(--ink2);text-align:right}
.brow.ref .bval{color:var(--teal);font-weight:600}
@media(max-width:560px){.brow{grid-template-columns:86px 1fr 40px;gap:9px}.blabel{font-size:12.5px}}

/* training-dynamics chart */
#train-chart svg{display:block}
.tlegend{display:flex;flex-wrap:wrap;gap:18px;margin-top:12px;font-size:13px;color:var(--mut)}
.tlegend span{display:inline-flex;align-items:center;gap:7px}
.tlegend i{width:13px;height:13px;border-radius:3px;display:inline-block;flex:none}

/* trace terminal */
#traceCard{transition:opacity .22s}#traceCard.fade{opacity:0}
#trace-meta span{font-family:var(--mono);font-size:11px;color:#9aa1ad;background:#23272f;border:1px solid #2f343d;padding:3px 9px;border-radius:6px}
#tline{background:#0e1013;border:1px solid #262a31;color:#cdd3db;font-family:var(--mono);font-size:13px;line-height:1.75;
  padding:14px 16px;border-radius:9px;white-space:pre-wrap;word-break:break-word;margin:0 0 13px}
#tline .hit{color:#ff9b86;font-weight:600;background:rgba(177,83,46,.24);border-radius:3px;padding:0 3px}
#trace-why{background:rgba(177,83,46,.1);border:1px solid rgba(207,113,72,.35);border-radius:9px;padding:11px 14px;font-size:14px;color:#f0cdbf}
.whylabel{display:block;font-size:10.5px;text-transform:uppercase;letter-spacing:.07em;color:#e08a66;font-weight:700;margin-bottom:4px}
.navbtn{width:30px;height:30px;border-radius:8px;border:1px solid #333842;background:#23272f;color:#cdd3db;font-size:15px;cursor:pointer;transition:.18s}
.navbtn:hover{background:#2c313a;color:#fff}
.dot{width:7px;height:7px;border-radius:50%;background:#363b44;cursor:pointer;transition:.2s}
.dot.on{background:#5b8fab;transform:scale(1.4)}

/* methods spec list */
.spec{display:grid;grid-template-columns:1fr;gap:0;margin:26px 0 0;border:1px solid var(--line);border-radius:11px;
  overflow:hidden;background:var(--surface);box-shadow:var(--sh,0 1px 2px rgba(30,25,15,.04))}
@media(min-width:640px){.spec{grid-template-columns:1fr 1fr}}
.spec>div{display:flex;flex-direction:column;gap:2px;padding:12px 16px;border-top:1px solid var(--line)}
.spec>div:nth-child(-n+1){border-top:0}
@media(min-width:640px){.spec>div:nth-child(2){border-top:0}}
.spec dt{font-family:var(--mono);font-size:10.5px;text-transform:uppercase;letter-spacing:.07em;color:var(--faint)}
.spec dd{margin:0;font-size:14px;color:var(--ink2);line-height:1.4}

/* technical aside */
.aside{background:#fbf8f1;border:1px solid var(--line);border-left:3px solid var(--steel);border-radius:0 10px 10px 0;
  padding:14px 18px;font-size:14.5px;line-height:1.6;color:var(--ink2)}
.aside b{color:var(--ink);font-weight:600}
.aside code{font-family:var(--mono);font-size:12.5px;background:var(--band);border:1px solid var(--line);
  border-radius:4px;padding:0 4px;color:var(--clay)}

/* crypt demo */
#demo-eqs{width:100%}
.eq{display:flex;align-items:baseline;gap:14px}
#demo-eqs .lab{font-size:11px;color:var(--faint);font-family:var(--sans);letter-spacing:.04em;width:42px;text-align:right;flex:none}
.g{display:inline-block;width:1.05em;text-align:center;font-weight:600}
.g.s1{color:var(--teal)}.g.s2{color:var(--clay)}.g.s3{color:var(--steel)}
.q{color:var(--mut)}
.box{border:1.5px solid var(--teal);border-radius:6px;padding:1px 9px;color:var(--teal);font-weight:600}
#demo-work .key{font-family:var(--mono);font-size:13.5px;color:var(--ink2);background:var(--band);border:1px solid var(--line);
  border-radius:6px;padding:7px 12px;display:inline-block;margin-bottom:11px}
#demo-work .fwd{font-family:var(--mono);font-size:14px;color:var(--ink);display:block;margin:3px 0;opacity:0;transform:translateX(-6px);transition:.4s}
#demo-work.show .fwd{opacity:1;transform:none}
#demo-work .search{color:var(--clay)}

/* code */
.code{background:var(--panel);color:#d9dde3;font-family:var(--mono);font-size:13px;line-height:1.7;padding:16px 18px;
  border-radius:11px;overflow-x:auto;white-space:pre}
.code .cmt{color:#7fae93}

/* scroll-reveal fade removed per preference: content is always visible. The .in class is
   still applied on scroll-into-view to drive the chart bar-fill and count-ups (data
   populating, not a fade); .reveal is otherwise inert. */
@media(prefers-reduced-motion:reduce){.bfill,#cheat-bar,#demo-work .fwd,#progress{transition:none}}

/* reading-progress bar */
#progress{position:fixed;top:0;left:0;height:3px;width:0;background:var(--teal);z-index:60;transition:width .08s linear}

/* section dot-nav (desktop only) */
#dotnav{position:fixed;right:18px;top:50%;transform:translateY(-50%);z-index:55;display:none;flex-direction:column;gap:11px}
@media(min-width:1120px){#dotnav{display:flex}}
#dotnav a{width:9px;height:9px;border-radius:50%;background:var(--line2);transition:.2s;position:relative;cursor:pointer}
#dotnav a:hover{background:var(--mut)}
#dotnav a.on{background:var(--teal);transform:scale(1.35)}
#dotnav a::after{content:attr(data-label);position:absolute;right:18px;top:50%;transform:translateY(-50%);
  white-space:nowrap;font-size:11.5px;color:var(--ink2);background:var(--surface);border:1px solid var(--line);
  border-radius:6px;padding:2px 9px;opacity:0;pointer-events:none;transition:.15s;box-shadow:var(--sh,0 6px 18px -10px rgba(30,25,15,.3))}
#dotnav a:hover::after{opacity:1}

/* signature demo (reuses .g / .box from the cipher demo) */
#sig-eq .lab{font-size:11px;color:var(--faint);margin-right:12px;font-family:var(--sans);letter-spacing:.04em}
#sig-eq .sig{font-family:var(--mono);font-size:14px;color:var(--steel);letter-spacing:.18em;font-weight:600}
#sig-work .srow{font-family:var(--mono);font-size:13.5px;color:var(--ink);display:block;margin:2px 0;opacity:0;transform:translateX(-6px);transition:.35s}
#sig-work.show .srow{opacity:1;transform:none}
#sig-work .skey{font-family:var(--mono);font-size:13px;color:var(--ink2);background:var(--band);border:1px solid var(--line);border-radius:6px;padding:6px 11px;display:inline-block;margin:2px 0 9px}
#sig-work .mut{color:var(--mut)}
#sig-work .big{font-family:var(--serif);font-size:18px;color:var(--teal);font-weight:500}

/* 0.85 vs 0.92 contrast panel */
.c85-row{display:grid;grid-template-columns:minmax(118px,210px) 1fr 54px;align-items:center;gap:14px;margin-bottom:12px}
.c85-label{font-size:14px;color:var(--ink2);line-height:1.2}
.c85-label small{display:block;font-family:var(--mono);font-size:10.5px;color:var(--faint);margin-top:2px}
.c85-track{height:26px;background:var(--band);border:1px solid var(--line);border-radius:7px;overflow:hidden}
.c85-fill{height:100%;border-radius:6px 0 0 6px}
.c85-fill.clay{background:linear-gradient(90deg,#b1532e,#cf7148)}
.c85-fill.teal{background:linear-gradient(90deg,#0f6b5f,#2c9183)}
.c85-num{font-family:var(--serif);font-size:23px;font-weight:500;text-align:right}
.c85-num.clay{color:var(--clay)}.c85-num.teal{color:var(--teal)}
.c85-cap{font-size:14px;color:var(--mut);line-height:1.55;margin:8px 0 0}
@media(max-width:560px){.c85-row{grid-template-columns:84px 1fr 44px;gap:9px}.c85-label{font-size:12.5px}}

/* references + inline citation links */
.lnk{color:var(--teal);text-decoration:underline;text-underline-offset:2px}
.lnk:hover{color:var(--tealD)}
.refs{border-top:1px solid var(--line);padding-top:18px}
.refs-title{font-family:var(--mono);font-size:11px;text-transform:uppercase;letter-spacing:.08em;color:var(--faint);margin-bottom:11px}
.refs ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:8px}
.refs li{font-size:13.5px;color:var(--ink2);line-height:1.5}
.refs li em{color:var(--ink);font-style:italic}

/* code copy button */
.code{position:relative}
.copy-btn{position:absolute;top:8px;right:8px;font-family:var(--sans);font-size:11px;color:#cdd3db;background:#23272f;
  border:1px solid #333842;border-radius:6px;padding:3px 9px;cursor:pointer;opacity:0;transition:.15s}
.code:hover .copy-btn{opacity:1}
.copy-btn:hover{background:#2c313a;color:#fff}
.copy-btn.done{color:#6fd0a0;border-color:#2a5a44;opacity:1}

/* heading anchor link */
.h2{position:relative}
.h2 .anchor{position:absolute;left:-0.85em;top:0.02em;color:var(--faint);text-decoration:none;opacity:0;font-weight:400;transition:.15s}
.h2:hover .anchor{opacity:1}
.h2 .anchor:hover{color:var(--teal)}
@media(max-width:920px){.h2 .anchor{display:none}}

/* smooth in-page navigation (dot-nav, anchors), offset for the sticky header */
html{scroll-behavior:smooth}
section[id],header[id]{scroll-margin-top:72px}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}#progress{transition:none}}