/* Jugami Algebra: "balance and notebook" theme. Deep teal ink, brass weights, coral highlights, lined paper. */
:root{
  --teal:#0b4f5c; --teal2:#136a7a; --teal-soft:#d7ecee; --ink:#22303a; --muted:#56636d;
  --paper:#fdfaf3; --paper2:#f3ecdc; --rule:rgba(11,79,92,.09); --margin:rgba(217,81,58,.25);
  --brass:#d99a1e; --brass-ink:#8a5a00; --coral:#d9513a; --coral-ink:#a8321f; --good:#2c7a4b; --bad:#b3261e;
  --radius:10px; --serif:"Iowan Old Style","Palatino Linotype",Palatino,"Book Antiqua",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}
body{margin:0;color:var(--ink);font-family:var(--sans);font-size:18px;line-height:1.65;background-color:var(--paper);
  background-image:linear-gradient(var(--rule) 1px,transparent 1px);background-size:100% 30px}
a{color:var(--coral-ink);text-underline-offset:2px}
a:hover{color:var(--teal)}
img,svg{max-width:100%;height:auto}
h1,h2,h3{font-family:var(--serif);color:var(--teal);line-height:1.2}
h2{font-size:1.75rem;margin:2.4em 0 .4em;scroll-margin-top:12px}
h2::after{content:"";display:block;width:64px;height:4px;border-radius:2px;background:linear-gradient(90deg,var(--brass) 50%,var(--coral) 50%);margin-top:.35em}
h3{font-size:1.2rem;margin:1.4em 0 .3em;scroll-margin-top:12px}
.skip{position:absolute;left:-999px;top:8px}
.skip:focus{left:8px;background:var(--teal);color:#fff;padding:8px 12px;z-index:10}
:focus-visible{outline:3px solid var(--brass);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:1040px;margin:0 auto;padding:0 18px}
.prose{max-width:40rem}
/* header */
.site-head{background:var(--teal);color:#fff;border-bottom:4px solid var(--brass)}
.site-head .bar{display:flex;align-items:center;gap:14px;flex-wrap:wrap;padding:10px 0}
.brand{display:flex;align-items:center;gap:10px;color:#fff;text-decoration:none;font-family:var(--serif);font-size:1.3rem;letter-spacing:.03em}
.brand img{width:36px;height:36px}
.brand:hover{color:#ffe2a8}
.head-nav{margin-left:auto;display:flex;flex-wrap:wrap;gap:6px}
.head-nav a{color:#fff;text-decoration:none;font-size:.9rem;padding:5px 11px;border:1px solid rgba(255,255,255,.35);border-radius:999px}
.head-nav a:hover,.head-nav a:focus-visible{background:var(--brass);border-color:var(--brass);color:var(--teal)}
.crumbs{font-size:.9rem;color:var(--muted);margin:14px 0 0}
.crumbs a{color:var(--muted)}
/* hero */
.hero{display:grid;grid-template-columns:1.15fr 1fr;gap:28px;align-items:center;padding:24px 0 8px}
.hero h1{font-size:clamp(2.1rem,5.5vw,3.3rem);margin:.1em 0 .2em}
.tagline{font-family:var(--serif);font-style:italic;font-size:1.25rem;color:var(--coral-ink);margin:0 0 .6em}
.hero figure{margin:0}
.btns{display:flex;flex-wrap:wrap;gap:10px;margin:14px 0}
.btn,button{font:inherit;font-size:1rem;cursor:pointer;border-radius:999px;padding:8px 16px;border:2px solid var(--teal);background:var(--teal);color:#fff;text-decoration:none;display:inline-block;min-height:44px}
.btn.ghost,button.ghost{background:#fff;color:var(--teal)}
.btn:hover,button:hover{background:var(--teal2);border-color:var(--teal2);color:#fff}
.btn.ghost:hover,button.ghost:hover{background:var(--teal-soft);color:var(--teal)}
button:disabled{opacity:.45;cursor:not-allowed}
/* toc + cards */
.toc{display:flex;flex-wrap:wrap;gap:8px;list-style:none;padding:0;margin:12px 0}
.toc a{display:block;padding:4px 12px;border:1px solid rgba(11,79,92,.35);border-radius:6px;text-decoration:none;color:var(--teal);background:rgba(255,255,255,.75);font-size:.95rem}
.toc a:hover{border-color:var(--teal);background:#fff}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:16px;list-style:none;padding:0;margin:16px 0}
.card{position:relative;background:#fff;border:1px solid #cfdfe2;border-radius:var(--radius);padding:16px 18px;height:100%}
.card h3{margin:.3em 0 .25em}
.card p{margin:.2em 0;font-size:.98rem}
.card svg{display:block;width:72px;height:72px}
.card.live{border:2px solid var(--teal);box-shadow:4px 4px 0 var(--brass)}
.card.live a::after{content:"";position:absolute;inset:0}
.tag{display:inline-block;font-size:.75rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;padding:2px 8px;border-radius:4px;background:var(--paper2);color:var(--muted)}
.tag.on{background:var(--brass);color:#2b1d00}
.soon-list{display:flex;flex-wrap:wrap;gap:8px;list-style:none;padding:0;margin:10px 0}
.soon-list li{padding:4px 12px;border:1px dashed var(--muted);border-radius:6px;color:var(--muted);font-size:.95rem;background:rgba(255,255,255,.6)}
/* math */
.m{font-family:var(--serif);font-style:italic;white-space:nowrap}
.eq{font-family:var(--serif);font-size:1.15rem;color:var(--teal)}
.formula{font-family:var(--serif);font-size:clamp(1.6rem,5vw,2.4rem);text-align:center;color:var(--teal);margin:.4em 0;letter-spacing:.03em}
/* aligned solution steps: equation on the left, what we did on the right */
.work{display:grid;grid-template-columns:minmax(0,auto) minmax(0,1fr);gap:2px 18px;background:#fff;border:1px solid #cfdfe2;border-left:5px solid var(--teal);border-radius:0 var(--radius) var(--radius) 0;padding:10px 14px;margin:10px 0;align-items:baseline}
.work .l{font-family:var(--serif);font-size:1.12rem;color:var(--ink);white-space:nowrap}
.work .r{font-size:max(17px,.93rem);color:var(--muted)}
.work .ans{font-weight:700;color:var(--good)}
.callout{border-left:5px solid var(--brass);background:#fff;padding:12px 16px;border-radius:0 var(--radius) var(--radius) 0;margin:16px 0}
.callout.teal{border-left-color:var(--teal)}
.callout.coral{border-left-color:var(--coral)}
.callout h3{margin-top:.1em}
.callout p:last-child{margin-bottom:0}
.two{display:grid;grid-template-columns:1fr 1fr;gap:22px;align-items:start}
.figure{margin:16px 0;background:#fff;border:1px solid #cfdfe2;border-radius:var(--radius);padding:12px}
.figure figcaption{font-size:.93rem;color:var(--muted);margin-top:6px}
table.data{border-collapse:collapse;background:#fff;margin:10px 0;font-size:.98rem}
table.data th,table.data td{border:1px solid #cfdfe2;padding:6px 12px;text-align:center}
table.data th{background:var(--paper2);color:var(--teal)}
.mistake{display:grid;grid-template-columns:auto 1fr;gap:4px 12px;background:#fff;border:1px solid #cfdfe2;border-radius:var(--radius);padding:12px 14px;margin:10px 0}
.mistake .x{color:var(--bad);font-weight:700}.mistake .ok{color:var(--good);font-weight:700}
/* reveal answers */
details.reveal{background:#fff;border:1px dashed var(--teal2);border-radius:var(--radius);padding:8px 14px;margin:10px 0}
details.reveal[open]{border-style:solid}
details.reveal summary{cursor:pointer;font-weight:600;color:var(--teal)}
details.reveal summary:focus-visible{outline:3px solid var(--brass)}
.problems{counter-reset:p;list-style:none;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:12px}
.problems>li{counter-increment:p;background:#fff;border:1px solid #cfdfe2;border-radius:var(--radius);padding:10px 14px}
.problems>li::before{content:counter(p) ".";font-weight:700;color:var(--coral-ink);margin-right:6px}
.problems details{margin-top:6px}
.problems summary{cursor:pointer;color:var(--teal);font-weight:600;font-size:max(17px,.95rem)}
.problems .work{margin:6px 0 0;padding:6px 10px}
/* widgets */
.widget{background:#fff;border:2px solid var(--teal);border-radius:var(--radius);padding:16px 18px;margin:16px 0;box-shadow:5px 5px 0 rgba(11,79,92,.15)}
.widget .help{color:var(--muted);font-size:max(17px,.95rem);margin-top:0}
.scale-wrap{display:grid;grid-template-columns:minmax(0,1.3fr) minmax(0,1fr);gap:18px;align-items:start}
.scale-wrap svg{width:100%;background:var(--paper);border-radius:8px}
.beam{transition:transform .5s cubic-bezier(.3,1.4,.6,1)}
.scale-eq{font-family:var(--serif);font-size:1.6rem;color:var(--teal);text-align:center;margin:.2em 0}
.scale-msg{min-height:3.2em;font-weight:600;margin:.4em 0}
.scale-msg.good{color:var(--good)}.scale-msg.bad{color:var(--bad)}
.ops{display:flex;flex-wrap:wrap;gap:8px}
.ops button{font-size:.95rem;padding:6px 12px}
.log{font-family:var(--mono);font-size:.9rem;color:var(--muted);background:var(--paper);border:1px dashed var(--teal2);border-radius:6px;padding:8px 10px;margin-top:10px;min-height:2.5em;white-space:pre-line}
.practice .q{font-family:var(--serif);font-size:1.5rem;color:var(--teal);min-height:1.6em;margin:.3em 0;text-align:center}
.practice .ptype{font-size:.85rem;text-transform:uppercase;letter-spacing:.06em;color:var(--coral-ink);font-weight:700;text-align:center;margin:0}
.practice form{display:flex;flex-wrap:wrap;gap:10px;align-items:center;justify-content:center}
.practice input[type=text]{font:inherit;font-size:1.15rem;width:8em;padding:6px 10px;border:2px solid var(--muted);border-radius:6px}
.practice select{font:inherit;font-size:1rem;padding:6px 8px;border:2px solid var(--muted);border-radius:6px;background:#fff}
.lvl{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin-bottom:6px}
.feedback{min-height:1.6em;font-weight:600;margin:.5em 0;text-align:center}
.feedback.good{color:var(--good)}.feedback.bad{color:var(--bad)}
.hint{color:var(--muted);font-style:italic;min-height:1.2em;text-align:center}
.practice .work{max-width:34rem;margin:10px auto}
.stats{display:flex;flex-wrap:wrap;gap:8px 18px;font-size:.95rem;color:var(--muted);border-top:1px dashed #cfdfe2;padding-top:8px;margin-top:10px}
.stats b{color:var(--teal);font-size:1.05rem}
.center{justify-content:center}
noscript p,.noscript{background:var(--paper2);border:1px dashed var(--muted);padding:10px 14px;border-radius:6px}
/* pager + footer */
.pager{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;margin:40px 0 10px;padding:14px 0;border-top:2px solid var(--teal)}
.pager a{text-decoration:none;font-weight:600;color:var(--teal)}
.pager a:hover{color:var(--coral-ink)}
.pager span{color:var(--muted)}
.sources li{margin:.3em 0}
.site-foot{margin-top:40px;background:var(--teal);color:#e6f1f2;font-size:.95rem;padding:18px 0 22px}
.site-foot p{margin:0}
.site-foot a{color:#ffe2a8}
.jugami-more{margin-top:8px}
.jugami-more span{font-weight:700;margin-right:4px}
@media (max-width:760px){.hero,.two,.scale-wrap{grid-template-columns:1fr}body{font-size:17px}.head-nav{display:none}
  .work{grid-template-columns:1fr}.work .r{margin:-2px 0 6px}.work .l{white-space:normal}}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}
.pan{transition:transform .5s cubic-bezier(.3,1.4,.6,1)}
.wordtree text{font-family:var(--serif)}
/* Review round 1: 44px tap targets */
summary{min-height:44px;display:flex;align-items:center;gap:8px;list-style:none;cursor:pointer}
summary::-webkit-details-marker{display:none}
summary::before{content:"";flex:none;width:0;height:0;border-style:solid;border-width:6px 0 6px 9px;border-color:transparent transparent transparent currentColor;transition:transform .15s}
details[open]>summary::before{transform:rotate(90deg)}
.toc a{min-height:44px;display:inline-flex;align-items:center}
.head-nav a{padding:10px 12px;min-height:44px;display:inline-flex;align-items:center;box-sizing:border-box}
.skip{padding:12px 16px}
.brand,.pager a,.jugami-more a{min-height:44px;display:inline-flex;align-items:center}
.practice input[type=text],.practice select{min-height:44px;box-sizing:border-box}
@media (prefers-reduced-motion:reduce){summary::before{transition:none}}