/* Summit Learn — /learn/ v2
   One ink family (navy), one accent (teal), lime = confirmed, amber = caution.
   Nothing else carries colour. Semantics are carried by rules and labels. */
:root{
  --bg:#F0F4FF; --surface:#ffffff; --surface2:#F4F7FF; --surface3:#E8EEFF;
  --ink:#0B3A4D; --off:#22485A; --muted:#4D5F75; --faint:#6D7F96;
  --rule:#E7ECF5; --border:#D8E0EC; --border-str:#C8D3E3;
  --teal:#1D8AAD; --teal-text:#15708C; --teal-soft:#F1F7FA; --teal-line:#BFD9E4;
  --lime:#8FCC28; --lime-dark:#6FA01E; --lime-soft:#F5FAEC;
  --amber:#F0B429; --amber-ink:#8A6100; --amber-soft:#FEF9EE;
  --wrong:#B3261E;
  --font:'Outfit',sans-serif; --r:14px; --rs:10px;
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:var(--font);background:var(--bg);color:var(--ink);line-height:1.62;
  font-size:16.5px;padding-bottom:3rem;-webkit-text-size-adjust:100%}
a{color:var(--teal-text)}
.wrap{max-width:900px;margin:0 auto;padding:1.4rem 1.1rem 0}
.wrap-n{max-width:900px;margin:0 auto;padding:0 1.1rem}

/* ---- topbar ---- */
.topbar{background:rgba(255,255,255,.92);backdrop-filter:blur(10px);
  border-bottom:1px solid var(--border);position:sticky;top:0;z-index:20}
.tb-in{max-width:900px;margin:0 auto;padding:.55rem 1.1rem;display:flex;align-items:center;gap:.9rem}
.back-btn{display:inline-flex;align-items:center;gap:5px;color:var(--muted);font-size:.85rem;
  text-decoration:none;white-space:nowrap;font-weight:500}
.back-btn:hover{color:var(--ink)}
.tb-crumb{font-size:.85rem;color:var(--faint);flex:1;min-width:0;overflow:hidden;
  text-overflow:ellipsis;white-space:nowrap}
.tb-crumb b{color:var(--muted);font-weight:500}
.tb-cta{font-size:.82rem;font-weight:600;color:var(--teal-text);border:1px solid var(--border-str);
  border-radius:9px;padding:.38rem .8rem;text-decoration:none;white-space:nowrap;background:#fff}
.tb-cta:hover{background:var(--teal-soft)}
.tb-portal{font-size:.82rem;color:var(--teal-text);text-decoration:none;font-weight:600;white-space:nowrap}

/* ---- sheet ---- */
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--r);
  padding:2.1rem 2.2rem;box-shadow:0 10px 30px rgba(11,58,77,.06)}
@media(max-width:640px){.card{padding:1.3rem 1.15rem;border-radius:12px}}

/* ---- masthead ---- */
.tags{display:flex;gap:.4rem;flex-wrap:wrap;margin-bottom:.7rem}
.tag{display:inline-block;background:var(--surface3);color:var(--teal-text);font-size:.66rem;
  font-weight:600;letter-spacing:.07em;padding:.24rem .55rem;border-radius:6px;text-transform:uppercase}
.tag.au{background:var(--surface2);color:var(--faint);border:1px solid var(--rule)}
h1{font-size:1.85rem;font-weight:600;letter-spacing:-.3px;line-height:1.18}
.acText{font-size:.83rem;color:var(--faint);margin-top:.45rem;max-width:62ch}
.intro{color:var(--off);font-size:1.02rem;line-height:1.6;font-style:normal;
  border-left:3px solid var(--lime);padding-left:.95rem;margin-top:1rem;max-width:66ch}
.prereq{display:flex;flex-wrap:wrap;align-items:center;gap:.4rem;margin-top:1.1rem;
  padding-top:.9rem;border-top:1px solid var(--rule)}
.prereq-l{font-size:.65rem;font-weight:600;letter-spacing:.1em;text-transform:uppercase;color:var(--faint)}
.pchip{font-size:.8rem;padding:.24rem .6rem;border-radius:99px;background:var(--surface2);
  color:var(--teal-text);border:1px solid var(--rule)}

/* ---- section headings: real headings, not labels ---- */
h2{font-size:1.16rem;font-weight:600;letter-spacing:-.1px;color:var(--ink);
  margin:2.3rem 0 1rem;padding-top:1.4rem;border-top:1px solid var(--rule);text-transform:none}
h2:first-of-type{margin-top:1.9rem}

/* ---- method rows (was .laws) ---- */
.laws{display:grid;gap:0}
.law{background:none;border:0;border-bottom:1px solid var(--rule);border-radius:0;
  padding:.95rem 0 1.05rem;display:grid;grid-template-columns:auto 1fr;gap:.1rem .8rem}
.law:last-child{border-bottom:0;padding-bottom:.2rem}
.law::before{content:"";grid-row:1/span 3;width:3px;border-radius:2px;background:var(--teal-line);align-self:stretch}
.law-t{font-weight:600;font-size:1rem;color:var(--ink);margin:0}
.law-m{margin:.45rem 0 .15rem;overflow-x:auto}
.law-d{font-size:.94rem;color:var(--muted);max-width:64ch}

/* ---- worked example ---- */
.eg{background:var(--surface2);border:1px solid var(--rule);border-left:3px solid var(--teal);
  border-radius:0 var(--rs) var(--rs) 0;padding:.9rem 1.1rem;margin-bottom:1.2rem}
.eg-l{display:inline-block;font-size:.64rem;font-weight:700;letter-spacing:.11em;text-transform:uppercase;
  color:var(--teal-text);margin-bottom:.3rem}

.steps{counter-reset:s;list-style:none}
.step{counter-increment:s;position:relative;padding:.72rem 0 .72rem 2.2rem}
.step::after{content:'';position:absolute;left:.8rem;top:0;bottom:0;width:1px;z-index:0;
  background:var(--teal-line);transform:translateX(-.5px)}
.step:first-child::after{top:1.5rem}
.step:last-child::after{bottom:calc(100% - 1.5rem)}
.step::before{content:counter(s);position:absolute;left:0;top:.68rem;width:1.6rem;height:1.6rem;z-index:1;
  background:var(--surface);color:var(--teal-text);border:1px solid var(--teal-line);border-radius:50%;
  display:grid;place-items:center;font-size:.8rem;font-weight:600;font-variant-numeric:tabular-nums}
.step-t{font-weight:500;font-size:1rem;color:var(--off);max-width:66ch}
.step-m{margin-top:.3rem;overflow-x:auto}
.step-t+.step-m{margin-left:.45rem}

/* ---- common mistakes: labels carry the colour, not panels ---- */
.errs{display:grid;gap:.2rem}
.err{background:none;border:0;border-bottom:1px solid var(--rule);border-radius:0;padding:1rem 0}
.err:last-child{border-bottom:0}
.err-pair{display:grid;grid-template-columns:1fr 1fr;gap:1.4rem}
@media(max-width:640px){.err-pair{grid-template-columns:1fr;gap:.8rem}}
.err-x,.err-y{min-width:0;overflow-x:auto;padding-left:.8rem;border-left:2px solid var(--rule)}
.err-x{border-left-color:#E3C4C1}
.err-y{border-left-color:var(--lime)}
.err-l{display:block;font-size:.63rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;margin-bottom:.25rem}
.err-l.bad{color:var(--wrong)}
.err-l.good{color:var(--lime-dark)}
.err-n{margin-top:.7rem;font-size:.94rem;color:var(--muted);line-height:1.55;max-width:66ch}

/* ---- practice ---- */
.tier{margin-bottom:1.5rem}
.tier-h{display:flex;align-items:baseline;gap:.6rem;flex-wrap:wrap;margin-bottom:.6rem}
.tier-b{font-size:.66rem;font-weight:700;letter-spacing:.09em;text-transform:uppercase;
  padding:.2rem .55rem;border-radius:6px;color:var(--teal-text);background:var(--teal-soft);
  border:1px solid var(--teal-line)}
.tier-reasoning .tier-b{color:var(--lime-dark);background:var(--lime-soft);border-color:#D4E7B0}
.tier-applied .tier-b{color:var(--amber-ink);background:var(--amber-soft);border-color:#EFDCB4}
.tier-d{font-size:.86rem;color:var(--muted);flex:1;min-width:12rem}
.prac-lead{font-size:.98rem;color:var(--muted);margin-bottom:.9rem;max-width:66ch}

.pq{display:grid;grid-template-columns:1.9rem minmax(0,1fr) auto;align-items:start;
  gap:.35rem .85rem;padding:.85rem 0;border-bottom:1px solid var(--rule);background:none;border-radius:0;margin:0}
.pq:last-child{border-bottom:0}
.pn{width:1.7rem;height:1.7rem;background:none;color:var(--teal-text);border:1px solid var(--teal-line);
  border-radius:50%;display:grid;place-items:center;font-size:.8rem;font-weight:600;
  font-variant-numeric:tabular-nums}
.tier-reasoning .pn,.tier-applied .pn{background:none;color:var(--teal-text)}
.pbody{min-width:0;overflow-x:auto;padding-top:.1rem}
.abtn{background:none;border:1px solid var(--border-str);color:var(--teal-text);font-family:var(--font);
  font-size:.78rem;font-weight:600;padding:.3rem .7rem;border-radius:8px;cursor:pointer;white-space:nowrap}
.abtn:hover{background:var(--teal-soft);border-color:var(--teal-line)}
.ans{grid-column:2/-1;margin-top:.5rem;padding:.6rem .85rem;background:var(--lime-soft);
  border-left:3px solid var(--lime);border-radius:0 8px 8px 0;display:none}
.ans.show{display:block}
.ans-l{display:block;font-size:.64rem;font-weight:700;letter-spacing:.09em;text-transform:uppercase;
  color:var(--lime-dark);margin-bottom:.25rem}
.revealall{background:none;color:var(--teal-text);border:1px solid var(--border-str);font-family:var(--font);
  font-size:.8rem;font-weight:600;padding:.4rem .85rem;border-radius:8px;cursor:pointer;margin-bottom:.7rem}
.revealall:hover{background:var(--teal-soft)}

/* ---- next step ---- */
.nextstep{margin-top:1.6rem;border:1px solid var(--rule);border-radius:var(--r);
  background:var(--surface2);padding:1.3rem 1.4rem;display:flex;align-items:center;
  gap:1.2rem;flex-wrap:wrap}
.ns-b{flex:1;min-width:14rem}
.ns-l{font-size:.65rem;font-weight:700;letter-spacing:.11em;text-transform:uppercase;color:var(--teal-text);
  margin-bottom:.25rem}
.ns-t{font-size:1.05rem;font-weight:600;margin-bottom:.2rem}
.ns-d{font-size:.92rem;color:var(--muted);max-width:52ch}
.ns-go{background:var(--lime);color:var(--ink);font-weight:600;font-size:.95rem;padding:.7rem 1.3rem;
  border-radius:10px;text-decoration:none;white-space:nowrap}
.ns-go:hover{background:var(--lime-dark);color:#fff}

/* ---- pager ---- */
.pager{display:grid;grid-template-columns:1fr 1fr;gap:.8rem;margin-top:1rem}
@media(max-width:560px){.pager{grid-template-columns:1fr}}
.pg{background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:.8rem 1rem;
  text-decoration:none;color:var(--ink);font-size:.95rem;font-weight:600;display:flex;flex-direction:column;gap:.15rem}
.pg:hover{border-color:var(--teal-line);background:var(--teal-soft)}
.pg span{font-size:.64rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--faint)}
.pg.next{text-align:right}
.pg.empty{background:none;border:none}

/* ---- maths + figures ---- */
.katex-display{margin:.35rem 0;overflow-x:auto;overflow-y:hidden;padding:.15rem 0}
.katex-display.fleqn{padding-left:0}
.pbody .katex-display,.ans .katex-display{margin:.1rem 0}
.law-m .katex-display,.eg-m .katex-display{text-align:left}
.law-m .katex-display>.katex,.eg .katex-display>.katex,.step-m .katex-display>.katex,.pbody .katex-display>.katex,.ans .katex-display>.katex{text-align:left}
.step-m .katex-display,.pbody .katex-display,.ans .katex-display{text-align:left;padding-left:0}
.tex-err{background:#FDECEC;color:var(--wrong);border:1px solid #F0CFCD;border-radius:4px;
  padding:.1rem .35rem;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:.85rem}
.viz{margin:.7rem 0;padding:.8rem;background:var(--surface2);border:1px solid var(--rule);
  border-radius:var(--rs);text-align:center;max-width:420px;margin-left:auto;margin-right:auto}
.viz svg{display:block;margin:0 auto;max-width:100%;height:auto}
.step-v .viz{max-width:340px}
.viz-n{font-size:.9rem;color:var(--muted);margin-top:.5rem}

/* ---- primary (Y4–6): larger type, fewer boxes ---- */
.primary{font-size:17.5px}
.primary h1{font-size:1.95rem}
.primary h2{font-size:1.2rem}
.primary .step-t,.primary .turn-q{font-size:1.05rem}
.bigidea{background:var(--lime-soft);border:1px solid #D9EBBB;border-left:3px solid var(--lime);
  border-radius:0 var(--r) var(--r) 0;padding:1.1rem 1.25rem;margin-top:1.1rem}
.bi-l{display:block;font-size:.65rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;
  color:var(--lime-dark);margin-bottom:.3rem}
.bigidea p{font-size:1.08rem;line-height:1.55;color:var(--ink);max-width:60ch}
.words{display:grid;gap:0}
.word{display:grid;grid-template-columns:10rem 1fr;gap:.8rem;background:none;border-bottom:1px solid var(--rule);
  border-radius:0;padding:.7rem 0;align-items:baseline}
.word:last-child{border-bottom:0}
@media(max-width:560px){.word{grid-template-columns:1fr;gap:.15rem}}
.word dt{font-weight:600;font-size:.98rem;color:var(--teal-text)}
.word dd{font-size:.96rem;color:var(--muted)}
.walk,.why{background:var(--surface2);border:1px solid var(--rule);border-left:3px solid var(--teal);
  border-radius:0 var(--rs) var(--rs) 0;padding:1.1rem 1.2rem}
.walk-lead,.why-lead{font-size:1.02rem;font-weight:600;margin-bottom:.7rem;color:var(--ink)}
.beat{display:flex;gap:.8rem;padding:.5rem 0}
.beat-n{flex:0 0 1.6rem;height:1.6rem;background:none;color:var(--teal-text);border:1px solid var(--teal-line);
  border-radius:50%;display:grid;place-items:center;font-size:.8rem;font-weight:600}
.beat-b{flex:1;min-width:0}
.beat-b p{font-size:.98rem;line-height:1.6;color:var(--off);max-width:64ch}
.walk-close,.why-close{margin-top:.8rem;padding-top:.8rem;border-top:1px solid var(--rule);font-size:.96rem;color:var(--muted)}
.why-row{padding:.4rem 0}
.why-t{font-size:.96rem;color:var(--off)}
.why-m{margin-top:.2rem}
.turn{background:none;border:0;border-bottom:1px solid var(--rule);border-radius:0;
  padding:.9rem 0;margin:0}
.turn:last-child{border-bottom:0}
.turn-h{display:flex;align-items:baseline;gap:.6rem;flex-wrap:wrap}
.turn-q{flex:1;min-width:11rem;font-size:1rem;font-weight:500;color:var(--ink)}
.turn-lvl{font-size:.62rem;font-weight:700;letter-spacing:.09em;text-transform:uppercase;
  color:var(--faint);white-space:nowrap}
.turn .viz{background:var(--surface2)}
.turn .abtn{margin-top:.6rem}
.turn .ans{margin-top:.55rem;font-size:.95rem;display:none}
.hint{margin-top:.6rem}
.hint summary{font-size:.85rem;color:var(--amber-ink);cursor:pointer;font-weight:600}
.hint p{margin-top:.4rem;font-size:.93rem;color:var(--muted);background:var(--amber-soft);
  border:1px solid #EFDCB4;border-radius:8px;padding:.55rem .75rem;max-width:64ch}

@media print{
  .topbar,.abtn,.revealall,.pager,.nextstep,.tb-cta{display:none}
  .ans{display:block!important}
  body{background:#fff;font-size:11pt}
  .card{box-shadow:none;border:0;padding:0}
  h2{break-after:avoid}
  .law,.step,.pq{break-inside:avoid}
}

/* ============ hub (learn/index.html) ============ */
.hero{background:var(--surface);border-bottom:1px solid var(--border);color:var(--ink);padding:2.2rem 0 2rem}
.hero h1{font-size:2rem;font-weight:600;letter-spacing:-.3px}
.hero p{color:var(--muted);font-size:1.02rem;margin-top:.4rem;max-width:46rem;font-weight:300}
.selbar{display:grid;grid-template-columns:repeat(3,1fr);gap:.8rem;background:var(--surface);
  border:1px solid var(--border);border-radius:var(--r);padding:1.1rem;
  box-shadow:0 8px 24px rgba(11,58,77,.05);margin-bottom:2rem}
.selbar.s4{grid-template-columns:repeat(4,1fr)}
@media(max-width:640px){.selbar,.selbar.s4{grid-template-columns:1fr}}
.field label{display:block;font-size:.67rem;font-weight:600;letter-spacing:.1em;
  text-transform:uppercase;color:var(--faint);margin-bottom:.35rem}
select,input[type=search]{width:100%;font-family:var(--font);font-size:.95rem;font-weight:500;
  color:var(--ink);background:var(--surface2);border:1px solid var(--border);
  border-radius:var(--rs);padding:.62rem .78rem;min-height:42px}
select{appearance:none;cursor:pointer;padding-right:2rem;
  background-image:url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%236D7F96' stroke-width='2'><path d='M6 9l6 6 6-6'/></svg>");
  background-repeat:no-repeat;background-position:right .65rem center;background-size:1.05rem}
select:focus-visible,input:focus-visible{outline:2px solid var(--teal);outline-offset:1px}

.yr{margin-bottom:2.4rem}
.yr[hidden]{display:none}
.yr-h{display:flex;align-items:baseline;gap:.8rem;margin-bottom:.9rem;
  padding-bottom:.6rem;border-bottom:1px solid var(--rule)}
.yr-h h2{font-size:1.2rem;font-weight:600;white-space:nowrap;margin:0;padding:0;border:0}
.bar{display:none}
.pct{font-size:.8rem;font-weight:500;color:var(--faint);margin-left:auto}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:.8rem}
.gcard{display:flex;flex-direction:column;gap:.3rem;background:var(--surface);
  border:1px solid var(--border);border-radius:12px;padding:.95rem 1.05rem;
  text-decoration:none;color:var(--ink);transition:border-color .12s,background .12s}
.gcard:hover{background:var(--teal-soft);border-color:var(--teal-line)}
.gcard[hidden]{display:none}
.gc-top{display:flex;align-items:center;justify-content:space-between;gap:.4rem}
.gc-topic{font-size:.66rem;font-weight:600;letter-spacing:.08em;text-transform:uppercase;color:var(--teal-text)}
.gc-rich{font-size:.58rem;font-weight:600;letter-spacing:.07em;text-transform:uppercase;
  background:none;color:var(--faint);border:1px solid var(--rule);padding:.08rem .38rem;border-radius:5px}
.gc-rich.prim{background:none;color:var(--faint)}
.gc-t{font-size:1rem;font-weight:600;line-height:1.35}
.gc-ac{display:none}
.none{font-size:.95rem;color:var(--muted);padding:.6rem 0}
.todo{margin-top:.9rem}
.todo summary{font-size:.82rem;color:var(--faint);cursor:pointer;padding:.3rem 0}
.chips{display:flex;flex-wrap:wrap;gap:.35rem;padding-top:.5rem}
.chip{font-size:.74rem;padding:.24rem .6rem;border-radius:20px;background:var(--surface2);
  color:var(--muted);border:1px solid var(--rule)}