/* Jugami Calculus: "Principia" theme. Laid paper, oxblood title plates, iron-gall ink,
   gilt rules, and a single ink-blue for curves. Swap the whole look via the custom properties. */
:root{
  --ink:#2a1e17; --ink2:#4a3a2e; --sepia:#6b5435; --paper:#f6efdd; --paper2:#ede2c6; --card:#fffaf0;
  --ox:#6e1a24; --ox2:#8c2633; --gilt:#b38a36; --gilt2:#d9b866; --curve:#1d4a73; --left:#a3301f; --right:#1d4a73;
  --good:#2e6b3f; --bad:#a3301f; --rule:#cdbb93;
  --radius:6px;
  --serif:"Iowan Old Style","Palatino Linotype",Palatino,"Book Antiqua","URW Palladio L",Georgia,serif;
  --sans:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --mono:ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{margin:0;color:var(--ink);font-family:var(--serif);font-size:18px;line-height:1.65;background:var(--paper);
  background-image:repeating-linear-gradient(90deg,rgba(107,84,53,.035) 0 1px,transparent 1px 7px),
    radial-gradient(ellipse at top,rgba(255,250,235,.9),rgba(246,239,221,0) 70%)}
a{color:var(--ox2);text-underline-offset:2px}
a:hover{color:var(--ox)}
img,svg{max-width:100%;height:auto}
h1,h2,h3{font-family:var(--serif);color:var(--ox);line-height:1.2;font-weight:600}
h2{font-size:1.8rem;margin:2.2em 0 .5em;scroll-margin-top:12px}
h2 .kicker{display:block;font-size:.8rem;letter-spacing:.22em;text-transform:uppercase;color:var(--sepia);font-weight:400;margin-bottom:.35em}
h2::after{content:"";display:block;width:120px;height:5px;margin-top:.4em;border-top:1px solid var(--gilt);border-bottom:1px solid var(--gilt)}
h3{font-size:1.25rem;margin:1.5em 0 .3em;color:var(--ink)}
p{margin:.6em 0}
.skip{position:absolute;left:-999px;top:8px}
.skip:focus{left:8px;background:var(--ox);color:#fff;padding:8px 12px;z-index:10}
:focus-visible{outline:3px solid var(--gilt);outline-offset:2px}
.visually-hidden{position:absolute!important;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.wrap{max-width:1060px;margin:0 auto;padding:0 18px}
.prose{max-width:41rem}
/* header */
.site-head{background:var(--ox);color:#fff;border-bottom:4px double var(--gilt2)}
.site-head .bar{display:flex;align-items:center;gap:14px;flex-wrap:wrap;padding:10px 18px}
.brand{display:flex;align-items:center;gap:10px;color:#fff;text-decoration:none;font-size:1.3rem;letter-spacing:.06em;font-variant:small-caps}
.brand img{width:36px;height:36px}
.brand:hover{color:var(--gilt2)}
.head-nav{margin-left:auto;display:flex;flex-wrap:wrap;gap:6px}
.head-nav a{color:#fff;text-decoration:none;font-family:var(--sans);font-size:.88rem;padding:5px 11px;border:1px solid rgba(217,184,102,.55);border-radius:3px}
.head-nav a:hover,.head-nav a:focus-visible{background:var(--gilt2);color:var(--ox)}
.crumbs{font-family:var(--sans);font-size:.88rem;color:var(--sepia);margin:14px 0 0}
.crumbs a{color:var(--sepia)}
/* hero */
.hero{display:grid;grid-template-columns:1.15fr 1fr;gap:30px;align-items:center;padding:22px 0 6px}
.hero h1{font-size:clamp(2.3rem,6vw,3.6rem);margin:.05em 0 .15em;letter-spacing:.02em}
.tagline{font-style:italic;font-size:1.28rem;color:var(--sepia);margin:0 0 .6em}
.hero figure{margin:0}
.plate{background:var(--card);border:1px solid var(--sepia);outline:4px double var(--rule);outline-offset:4px;border-radius:2px;padding:10px;margin:10px}
.plate figcaption,.fig figcaption{font-size:.92rem;color:var(--ink2);font-style:italic;margin-top:6px;text-align:center}
.fig{margin:18px 0}
.fig svg{display:block;margin:0 auto}
.btns{display:flex;flex-wrap:wrap;gap:10px;margin:14px 0}
.btn,button{font-family:var(--sans);font-size:1rem;cursor:pointer;border-radius:3px;padding:8px 16px;border:2px solid var(--ox);background:var(--ox);color:#fff;text-decoration:none;display:inline-block;line-height:1.3}
.btn.ghost,button.ghost{background:transparent;color:var(--ox)}
.btn:hover,button:hover{background:var(--ox2);border-color:var(--ox2);color:#fff}
button:disabled{opacity:.5;cursor:not-allowed}
/* toc + cards */
.toc{display:flex;flex-wrap:wrap;gap:8px;list-style:none;padding:0;margin:12px 0;font-family:var(--sans)}
.toc a{display:block;padding:4px 12px;border:1px solid var(--rule);border-radius:3px;text-decoration:none;color:var(--ox);background:rgba(255,250,240,.75);font-size:.92rem}
.toc a:hover{border-color:var(--ox)}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:18px;list-style:none;padding:0;margin:18px 0;counter-reset:book}
.card{position:relative;background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:16px 18px 14px;box-shadow:0 1px 0 var(--paper2),0 6px 18px rgba(74,58,46,.08)}
.card .book{font-size:.78rem;letter-spacing:.2em;text-transform:uppercase;color:var(--sepia)}
.card h3{margin:.2em 0 .3em;color:var(--ox)}
.card p{margin:.3em 0;font-size:.98rem}
.card svg{width:76px;height:76px;float:right;margin:0 0 6px 10px}
.card.soon{background:rgba(255,250,240,.55);border-style:dashed}
.card.soon h3{color:var(--ink2)}
.card.live{border-color:var(--ox);border-width:2px}
.tag{display:inline-block;font-family:var(--sans);font-size:.72rem;font-weight:600;letter-spacing:.08em;text-transform:uppercase;padding:2px 8px;border-radius:2px;background:var(--paper2);color:var(--ink2)}
.tag.on{background:var(--ox);color:#fff}
.card.live h3 a{text-decoration:none}
.card.live h3 a::after{content:"";position:absolute;inset:0}
.card.live:hover{box-shadow:0 0 0 3px var(--gilt2)}
/* math */
.m{font-family:var(--serif);white-space:nowrap}
var{font-style:italic}
.frac{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;margin:0 .15em;line-height:1.15}
.frac>.num{border-bottom:1.5px solid currentColor;padding:0 .2em .05em}
.frac>.den{padding:.05em .2em 0}
.lim{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;line-height:1;margin-right:.2em}
.lim>.sub{font-size:.68em;margin-top:.2em;white-space:nowrap}
.display{display:block;text-align:center;font-size:1.2rem;margin:14px 0;padding:10px;background:var(--card);border-left:4px solid var(--gilt);overflow-x:auto}
.def{background:var(--card);border:1px solid var(--rule);border-left:5px solid var(--ox);padding:12px 18px;margin:16px 0;max-width:41rem}
.def strong:first-child{color:var(--ox);font-variant:small-caps;letter-spacing:.05em}
.note{background:rgba(179,138,54,.12);border-left:4px solid var(--gilt);padding:10px 16px;max-width:41rem;margin:14px 0}
/* worked steps */
.example{background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:4px 20px 14px;margin:18px 0}
.example h3{margin-top:.8em}
.work{display:grid;grid-template-columns:minmax(0,max-content) 1fr;gap:6px 22px;align-items:center;margin:10px 0;font-size:1.05rem}
.work .l{font-family:var(--serif);white-space:nowrap;overflow-x:auto}
.work .r{font-family:var(--sans);font-size:.9rem;color:var(--ink2)}
.work .ans{font-weight:700;color:var(--ox)}
.check{font-family:var(--sans);font-size:.92rem;color:var(--good);margin:.4em 0}
/* figures row */
.trio{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin:16px 0}
.trio figure{margin:0;background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:10px}
.trio h3{font-size:1.05rem;margin:.2em 0}
.trio p{font-size:.95rem;margin:.3em 0}
/* widgets */
.widget{background:var(--card);border:1px solid var(--sepia);border-radius:var(--radius);padding:16px 18px;margin:18px 0;box-shadow:0 6px 20px rgba(74,58,46,.10)}
.widget .help{font-family:var(--sans);font-size:.92rem;color:var(--ink2);margin:0 0 10px}
.wgrid{display:grid;grid-template-columns:1.25fr 1fr;gap:20px;align-items:start}
.graph{background:#fffdf7;border:1px solid var(--rule);border-radius:4px;display:block;width:100%;height:auto}
.controls{font-family:var(--sans);font-size:.95rem}
.controls label{display:block;font-weight:600;margin:6px 0 4px}
.controls select{font:inherit;padding:6px 8px;border:1px solid var(--sepia);border-radius:3px;background:#fff;width:100%}
input[type=range]{width:100%;accent-color:var(--ox)}
.readout{font-family:var(--sans);font-size:.95rem;margin:8px 0}
.verdict{border-left:4px solid var(--gilt);background:rgba(179,138,54,.1);padding:8px 12px;font-family:var(--sans);font-size:.95rem;min-height:3.2em}
table.vals{border-collapse:collapse;width:100%;font-family:var(--mono);font-size:.82rem;margin:10px 0}
table.vals caption{font-family:var(--sans);font-size:.85rem;text-align:left;color:var(--ink2);padding-bottom:4px}
table.vals th,table.vals td{border:1px solid var(--rule);padding:3px 6px;text-align:right}
table.vals th{font-family:var(--sans);background:var(--paper2);font-weight:600}
table.vals tr.now td{background:#fbe9b7;font-weight:700}
table.vals tr.later td{color:#b9a98a}
.lc{color:var(--left)} .rc{color:var(--right)}
.noscript{background:#fff3cd;border:1px solid var(--gilt);padding:10px 14px;font-family:var(--sans);font-size:.95rem}
/* practice */
.problems{list-style:none;padding:0;margin:14px 0;display:grid;gap:10px;counter-reset:prob}
.problems>li{background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:10px 16px;counter-increment:prob}
.problems>li>p:first-child::before{content:counter(prob) ". ";font-weight:700;color:var(--ox)}
.problems .lvl{font-family:var(--sans);font-size:.75rem;text-transform:uppercase;letter-spacing:.08em;color:var(--sepia);margin-left:6px}
details.reveal summary{cursor:pointer;font-family:var(--sans);font-size:.92rem;color:var(--ox);font-weight:600;padding:4px 0}
details.reveal[open] summary{margin-bottom:4px}
/* quiz */
.quiz fieldset{border:1px solid var(--rule);border-radius:var(--radius);background:var(--card);margin:12px 0;padding:10px 16px 12px}
.quiz legend{font-weight:600;padding:0 6px;color:var(--ink)}
.quiz .opts{display:grid;gap:4px;margin-top:4px}
.quiz label{display:flex;gap:10px;align-items:center;padding:5px 8px;border-radius:4px;cursor:pointer}
.quiz label:hover{background:var(--paper2)}
.quiz input[type=radio]{accent-color:var(--ox);width:18px;height:18px;flex:none}
.quiz label.right{background:#dcefdc;outline:2px solid var(--good)}
.quiz label.wrong{background:#f6dcd6;outline:2px solid var(--bad)}
.quiz .why{font-family:var(--sans);font-size:.92rem;color:var(--ink2);margin:.5em 0 0}
.stats{display:flex;flex-wrap:wrap;gap:18px;font-family:var(--sans);margin:10px 0}
.stats b{color:var(--ox)}
.qmsg{font-family:var(--sans);font-weight:600}
/* lists */
ul.sources{padding-left:1.2em}
ul.sources li{margin:.4em 0;font-size:.97rem}
.mistakes{padding-left:1.2em}
.mistakes li{margin:.5em 0}
.pager{display:flex;flex-wrap:wrap;justify-content:space-between;gap:12px;font-family:var(--sans);margin:40px 0 10px;padding:14px 0;border-top:3px double var(--rule)}
.pager .soon{color:var(--sepia)}
/* footer */
.site-foot{margin-top:40px;background:var(--ink);color:#efe6d2;padding:22px 0;font-size:.95rem;border-top:4px double var(--gilt)}
.site-foot a{color:var(--gilt2)}
.jugami-more{margin-top:10px}
.jugami-more span{font-weight:600;margin-right:4px}
@media (max-width:760px){
  body{font-size:17.5px}
  .hero,.wgrid{grid-template-columns:1fr}
  .trio{grid-template-columns:1fr}
  .head-nav{margin-left:0}
  .work{grid-template-columns:1fr;gap:2px}
  .work .r{margin-bottom:6px}
  .display{font-size:1.05rem}
  .card svg{width:60px;height:60px}
}
@media (max-width:760px){.graph text{font-size:20px}}

/* ---- Round 1 (Mandy): 44px tap targets ---- */
.skip:focus,.site-head a,.head-nav a,.crumbs a,.toc a,.btn,.hero a,button,.pager a,.site-foot a{min-height:44px;display:inline-flex;align-items:center}
.brand{min-height:44px}
.head-nav a,.toc a{padding-top:0;padding-bottom:0}
.btn,button{padding-top:0;padding-bottom:0;justify-content:center}
.controls select{min-height:44px}
input[type=range]{height:44px;margin:0}
details.reveal summary{min-height:44px;display:flex;align-items:center;gap:8px;list-style:none;padding:0}
details.reveal summary::-webkit-details-marker{display:none}
details.reveal summary::before{content:"\25B8";font-size:.9em}
details.reveal[open] summary::before{content:"\25BE"}
.quiz label{min-height:44px;padding-top:4px;padding-bottom:4px;flex-wrap:wrap}
.site-foot a{vertical-align:middle}
/* ---- Quiz feedback in text, not colour alone ---- */
.quiz label .fb{font-family:var(--sans);font-size:.85rem;font-weight:700;margin-left:auto;padding-left:6px}
.quiz label.right .fb{color:#1f5a2a}
.quiz label.wrong .fb{color:#8a1f12}
/* Whole live card is the tap target (stretched link), and the heading link itself is 44px tall */
.card.live h3 a{min-height:44px;display:inline-flex;align-items:center}
.card.live h3 a::after{content:"";position:absolute;inset:0;border-radius:var(--radius)}
.card.live:focus-within{outline:3px solid var(--gilt);outline-offset:2px}
.card.live h3 a:focus-visible{outline:none}
main:focus{outline:none}