/* Biology notes — presentation layer.
   Design tokens, panels, tabs, worked-example rows and the level filter are lifted from
   the shared notes system used by /phy/notes-c1/ and /chem/notes-c5/ so Biology reads as
   another subject on the same site. Content lives in ../content/*.json; nothing here
   knows any biology. */
:root{
  --cream:#f5f2ea; --paper:#fdfcf8; --ink:#2b3947; --ink-soft:#5b6b7c;
  --navy:#33506d; --navy-deep:#2a4058; --blue:#4a9fe3; --blue-soft:#dcecfa;
  --amber:#e8a13c; --green:#4caf7d; --red:#e05a4e;
  --ok-bg:#e7f2e4; --ok-bd:#7fb069; --ok-tx:#2e6b34; --no-bg:#fdf1f0; --no-bd:#e0b3ab; --no-tx:#b23b30;
  --line:#e3ddcc;
  --card-shadow:0 6px 24px rgba(43,57,71,.10),0 2px 6px rgba(43,57,71,.08);
  --radius:16px; font-size:16px;
  --parchment:#efe3c8; --frame-dark:#8a6f3c; --gold:#d9a441; --bg:#0c0f14; --bg-2:#11161e;
  --pixel:'MinecraftFont',ui-monospace,'Cascadia Mono',monospace;
  --bar-h:48px;
}
*{box-sizing:border-box}
html,body{margin:0;padding:0;background:var(--cream);color:var(--ink);
  font-family:"Segoe UI",system-ui,-apple-system,"Helvetica Neue",Arial,sans-serif;-webkit-font-smoothing:antialiased}
html{scroll-padding-top:calc(var(--bar-h) + 120px)}
a{color:var(--navy)}
h1,h2,h3{font-weight:700;letter-spacing:-.01em}
:focus-visible{outline:3px solid var(--blue);outline-offset:2px}
.skip{position:absolute;left:-999px;top:0;background:var(--gold);color:#3a2c08;padding:8px 12px;z-index:100;font-weight:700}
.skip:focus{left:8px;top:8px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* ---------------- site chrome (pixel bar, same as the other notes) ---------------- */
.chrome{position:sticky;top:0;z-index:60;background:linear-gradient(180deg,var(--bg-2),var(--bg));border-bottom:3px solid var(--frame-dark);color:var(--parchment)}
.bar{display:flex;align-items:center;gap:8px;flex-wrap:wrap;padding:7px 12px}
.chrome a,.chrome button{font-family:var(--pixel)}
.cbtn,.back,.content-btn,.subj-btn,.pn-btn,.fs-btn{font-size:9px;letter-spacing:.04em;text-transform:uppercase;text-decoration:none;cursor:pointer;color:var(--gold);
  background:rgba(217,164,65,.12);border:2px solid var(--frame-dark);padding:5px 8px;display:inline-flex;align-items:center;gap:5px;white-space:nowrap}
.cbtn:hover,.back:hover,.content-btn:hover,.subj-btn:hover,.pn-btn:hover,.fs-btn:hover,
.content-btn[aria-expanded="true"],.subj-btn[aria-expanded="true"]{background:var(--gold);color:#3a2c08}
.chrome :focus-visible{outline:3px solid var(--parchment);outline-offset:2px}
.ttl{font-family:var(--pixel);font-size:12px;letter-spacing:.03em;color:var(--parchment);margin:0}
.nav-group{margin-left:auto;display:flex;align-items:center;gap:6px;flex-wrap:wrap;justify-content:flex-end}
.subj-wrap,.content-wrap{position:relative;display:inline-flex}
.chev{font-size:.72rem;transition:transform .15s}
[aria-expanded="true"]>.chev{transform:rotate(180deg)}
.menu{position:absolute;top:calc(100% + 7px);z-index:1000;max-width:92vw;max-height:min(72vh,560px);overflow-y:auto;background:var(--bg-2);border:2px solid var(--frame-dark);border-radius:10px;box-shadow:0 12px 34px rgba(0,0,0,.55);padding:6px}
.menu[hidden]{display:none}
.subj-menu{left:0;width:264px}
.content-menu{right:0;width:380px}
.menu a,.menu .cur{display:flex;gap:11px;align-items:center;text-decoration:none;color:var(--parchment);padding:9px 11px;border-radius:7px;font-family:'Segoe UI',system-ui,sans-serif;font-size:.9rem;line-height:1.25}
.menu a:hover,.menu a:focus-visible{background:rgba(217,164,65,.16);color:var(--gold);outline:none}
.menu .cur{opacity:.55;cursor:default;background:rgba(217,164,65,.05)}
.menu .num{font-family:var(--pixel);font-size:.7rem;color:var(--gold);min-width:22px;text-align:right}
.menu small{display:block;font-size:.72rem;color:#9c8a63}
.menu .soon{opacity:.5;cursor:default}
.menu .soon:hover{background:none;color:var(--parchment)}
.sic{font-size:1.05em;line-height:1}
.band-wrap{display:flex;align-items:center;gap:6px}
.band-nudge{font-family:var(--pixel);font-size:9px;letter-spacing:.05em;text-transform:uppercase;color:#3a2c08;background:var(--gold);border:2px solid var(--frame-dark);padding:4px 7px;white-space:nowrap;animation:bandpulse 1.6s ease-in-out infinite}
.band-nudge[hidden]{display:none}
@keyframes bandpulse{0%,100%{transform:scale(1)}50%{transform:scale(1.06)}}
.band-seg{display:inline-flex;border:2px solid var(--frame-dark);overflow:hidden}
.band-seg button{font-size:9px;letter-spacing:.04em;text-transform:uppercase;cursor:pointer;color:var(--gold);background:rgba(217,164,65,.12);border:none;border-right:2px solid var(--frame-dark);padding:6px 7px;white-space:nowrap}
.band-seg button:last-child{border-right:none}
.band-seg button:hover{background:rgba(217,164,65,.3)}
.band-seg button[aria-pressed="true"]{background:var(--gold);color:#3a2c08}
.fs-btn .fs-out{display:none}
body.is-fs .fs-btn .fs-in{display:none}
body.is-fs .fs-btn .fs-out{display:inline}
@media (max-width:1100px){.band-nudge{display:none}.fs-label{display:none}}
@media (max-width:900px){.ttl{display:none}.pn-name{display:none}}
@media (max-width:560px){.band-seg button{padding:6px 5px}.content-menu{right:auto;left:0}}
@media print{.chrome,.site-logo,.chap-arrow,.cnav,.tabs{display:none!important}}

/* ---------------- notes document ---------------- */
.doc{max-width:900px;margin:0 auto;padding:26px 22px 90px}
.doc.wide{max-width:1180px}
.doc h1{color:var(--navy-deep);font-size:2rem;margin:0 0 6px}
.doc h2{color:var(--navy);border-bottom:2px solid #eee8d8;padding-bottom:6px;margin-top:4px}
.doc h3{color:var(--navy);margin:18px 0 6px}
.doc p,.doc li{line-height:1.6}
.doc .lead{color:var(--ink-soft);font-size:1.02rem;line-height:1.6;max-width:760px}
.panel{background:var(--paper);border-radius:var(--radius);box-shadow:var(--card-shadow);padding:24px 30px;margin-bottom:24px}
.doc table{border-collapse:collapse;width:100%;font-size:.92rem;margin:6px 0}
.doc th,.doc td{border:1px solid #e0dccd;padding:8px 10px;text-align:left;vertical-align:top}
.doc th{background:#f0ecdf}
.scroll-x{overflow-x:auto;-webkit-overflow-scrolling:touch}
.term{background:var(--blue-soft);border-radius:6px;padding:0 5px;font-weight:600}
.defbox{background:var(--blue-soft);border-left:4px solid var(--blue);border-radius:8px;padding:10px 14px;margin:12px 0}
.keybox{background:#fff8e8;border-left:4px solid var(--amber);border-radius:8px;padding:10px 14px;margin:12px 0}
.keybox b.kt{color:#9a6a12}
.keybox ul{margin:6px 0 0;padding-left:20px}
.fig-note{font-size:.86rem;color:#5a6a78;margin:6px 2px 12px}
.badge{display:inline-block;font-size:.68rem;font-weight:800;letter-spacing:.04em;text-transform:uppercase;border-radius:999px;padding:2px 9px;white-space:nowrap;vertical-align:middle}
.badge.all{background:var(--blue-soft);color:var(--blue)}
.badge.pure{background:#f3e9fa;color:#6b2f92}
.badge.tys{background:#e4e9f2;color:#33506d}
.badge.x{background:#fdefcf;color:#8a5a00}
.badge.soon{background:#f3dede;color:#b23b30}
.badge.ok{background:#e7f2e4;color:#2e6b34}

/* level (band) filter — fail-safe: no data-level on <html> means nothing hides */
html[data-level="pure"] [data-levels]:not([data-levels~="pure"]),
html[data-level="science"] [data-levels]:not([data-levels~="science"]),
html[data-level="g2"] [data-levels]:not([data-levels~="g2"]){display:none!important}
.band-banner{font-size:.9rem;color:#2f5a86;background:#dbe7f5;border:1px solid #a9c3e0;border-radius:10px;padding:10px 14px;margin:0 0 14px}
.band-banner b{color:var(--navy-deep)}

/* tabs */
.tabs{position:sticky;top:var(--bar-h);z-index:30;background:var(--cream);padding:10px 0 8px;margin:14px 0 18px}
.tablist{display:flex;gap:7px;flex-wrap:wrap;padding:0;margin:0;list-style:none}
.tablist button,.chip-btn{font:inherit;font-size:.9rem;font-weight:700;cursor:pointer;color:var(--navy);background:var(--paper);border:1px solid var(--line);
  border-radius:999px;padding:8px 13px;box-shadow:0 1px 3px rgba(43,57,71,.07);transition:background .12s,color .12s,border-color .12s;white-space:nowrap}
.tablist button:hover,.chip-btn:hover{background:#eef3f9;border-color:#c9d7e6}
.tablist button[aria-selected="true"],.chip-btn[aria-pressed="true"]{background:var(--navy);color:#fff;border-color:var(--navy);box-shadow:var(--card-shadow)}
.tablist .tabnum{opacity:.62;margin-right:6px}
.tabpanel[hidden]{display:none}
.tabpanel:focus{outline:none}
.cnav{display:flex;gap:6px;overflow-x:auto;padding:8px 2px 2px;margin:0;list-style:none;-webkit-overflow-scrolling:touch}
.cnav a{display:inline-flex;gap:6px;align-items:center;font-size:.8rem;font-weight:700;text-decoration:none;color:var(--navy);background:#fff;border:1px solid var(--line);border-radius:8px;padding:5px 9px;white-space:nowrap}
.cnav a:hover{border-color:var(--blue)}
.cnav a[aria-current="true"]{background:var(--blue-soft);border-color:var(--blue);color:var(--navy-deep)}
.cnav .n{font-weight:800;color:var(--blue)}

/* concept sections */
.concept{scroll-margin-top:calc(var(--bar-h) + 120px)}
.concept h2{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.concept h2 .cn{display:inline-flex;align-items:center;justify-content:center;min-width:34px;height:34px;border-radius:50%;background:var(--navy);color:#fff;font-size:1rem}
.fig{margin:14px auto 6px;text-align:center}
.fig .diagram{background:#fff;border:1px solid #ece7d8;border-radius:12px;padding:6px;overflow-x:auto}
.fig svg{display:block;width:100%;height:auto;min-width:520px}
.fig figcaption{font-size:.86rem;color:var(--ink-soft);margin-top:6px}
.fig.pending{background:#fbfaf6;border:1.6px dashed #cfc7ae;border-radius:12px;padding:18px;color:var(--ink-soft);font-size:.9rem}
.sub-h{font-size:.78rem;font-weight:800;letter-spacing:.06em;text-transform:uppercase;color:#7a8896;margin:26px 0 8px;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.sub-h::after{content:"";flex:1;border-top:1px dashed var(--line);min-width:20px}

/* reveal blocks, worked examples, rows (same card look as .wex) */
details.wex,details.qrow{background:var(--paper);border:1.6px solid var(--line);border-radius:12px;margin:10px 0;box-shadow:0 1px 3px rgba(43,57,71,.07)}
details.wex[open],details.qrow[open]{border-color:#c9d7e6}
details>summary{cursor:pointer;list-style:none;display:flex;align-items:center;gap:9px;padding:11px 14px;font-weight:600;color:var(--navy);flex-wrap:wrap}
details>summary::-webkit-details-marker{display:none}
details>summary::before{content:'\25B8';color:var(--blue);font-size:.9em}
details[open]>summary::before{content:'\25BE'}
.wex-body{padding:2px 16px 14px;border-top:1px dashed var(--line)}
.sum-main{flex:1 1 280px;min-width:0}
.sum-end{margin-left:auto;display:inline-flex;gap:6px;align-items:center}
.src{display:flex;flex-wrap:wrap;gap:5px 8px;margin:9px 0 2px;font-size:.74rem;font-weight:800;color:#5a6a78}
.src span{white-space:nowrap;border:1px solid #d8d2c2;border-radius:999px;padding:2px 8px;background:#f8f6ef}
.src span.cross{white-space:normal;background:#fdefcf;border-color:#e6cf93;color:#8a5a00}
.mk{font-weight:800;color:var(--blue);white-space:nowrap}
.qtext p{margin:8px 0}
.qtext .part{margin:10px 0 4px;padding-left:2px}
.qimg{margin:10px 0;text-align:center}
.qimg img{max-width:100%;height:auto;border:1px solid #ece7d8;border-radius:10px;background:#fff}
.qimg figcaption{font-size:.8rem;color:var(--ink-soft);margin-top:4px}
.zoomable{cursor:zoom-in}
.opts{list-style:none;padding:0;margin:10px 0 4px;display:grid;gap:8px}
.opts button{font:inherit;font-size:.93rem;width:100%;text-align:left;cursor:pointer;display:flex;gap:10px;align-items:baseline;background:#fff;border:1.6px solid var(--line);border-radius:10px;padding:9px 12px;color:inherit}
.opts button:hover:not(:disabled){border-color:var(--blue)}
.opts button[aria-pressed="true"]{border-color:var(--blue);background:#eef5fd;box-shadow:0 0 0 3px var(--blue-soft)}
.opts .ltr{font-weight:800;color:var(--blue);flex:0 0 auto}
.opts button.right{background:var(--ok-bg);border-color:var(--ok-bd)}
.opts button.wrong{background:var(--no-bg);border-color:var(--no-bd)}
.opts button:disabled{cursor:default}
.mcq-table td.pick,.mcq-table th.pick{width:1%;white-space:nowrap}
.mcq-table tr.sel td{background:#eef5fd}
.mcq-table tr.right td{background:var(--ok-bg)}
.mcq-table tr.wrong td{background:var(--no-bg)}
.mcq-table button{font:inherit;font-weight:800;cursor:pointer;color:var(--navy);background:#fff;border:1.6px solid var(--line);border-radius:8px;min-width:38px;padding:5px 9px}
.mcq-table button[aria-pressed="true"]{background:var(--navy);color:#fff;border-color:var(--navy)}
.mcq-table button:disabled{cursor:default}
.verdict{font-weight:700;margin:8px 0 2px}
.verdict.ok{color:var(--ok-tx)} .verdict.no{color:var(--no-tx)}
.try{margin:12px 0 4px}
.try label{font-size:.82rem;font-weight:700;color:#5a6a78;display:block;margin:0 0 4px}
.try textarea{width:100%;min-height:62px;font:inherit;font-size:.92rem;padding:9px 11px;border:1.6px solid var(--line);border-radius:10px;background:#fff;resize:vertical}
.try textarea:focus,.blank:focus,.dr-in:focus{outline:none;border-color:var(--blue);box-shadow:0 0 0 3px var(--blue-soft)}
input.blank{width:5.5em;font:inherit;text-align:center;border:1.6px solid var(--blue);border-radius:6px;padding:4px;background:#fff;color:var(--blue)}
input.blank.ok{border-color:var(--ok-bd);background:var(--ok-bg);color:var(--ok-tx)}
input.blank.no{border-color:var(--no-bd);background:var(--no-bg);color:var(--no-tx)}
.ctrl{display:flex;align-items:center;gap:9px;margin:10px 0 4px;flex-wrap:wrap}
.btn{font:inherit;font-size:.87rem;font-weight:800;cursor:pointer;color:var(--navy);background:var(--paper);border:1.6px solid var(--line);border-radius:999px;padding:7px 15px}
.btn:hover:not(:disabled){border-color:var(--blue)}
.btn.primary{background:var(--navy);color:#fff;border-color:var(--navy)}
.btn:disabled{opacity:.45;cursor:not-allowed}
.answer{margin:10px 0 0;border-left:3px solid var(--ok-bd);background:#f4f9f2;border-radius:0 8px 8px 0;padding:8px 14px}
.answer[hidden]{display:none}
.answer .alabel{font-size:.74rem;font-weight:800;letter-spacing:.05em;text-transform:uppercase;color:var(--ok-tx);margin:0 0 2px}
.answer .anote{font-size:.8rem;color:#5a6a78;margin:6px 0 0}
.answer ul.pts{list-style:none;padding:0;margin:6px 0}
.answer ul.pts li{display:flex;gap:8px;align-items:flex-start;margin:3px 0}
.answer ul.pts input{margin-top:.4em}
.answer .partlab{font-weight:800;color:var(--blue)}
.distract{font-size:.88rem;color:#5a6a78;margin:6px 0 0;padding-left:18px}
.selfscore{font-size:.85rem;font-weight:700;color:var(--ok-tx)}
.student{color:var(--ok-tx)}   /* student answers green, model answers red in the practical format; here the suggested answer keeps the calmer green panel */
.also{display:flex;gap:10px;align-items:center;flex-wrap:wrap;background:#f8f6ef;border:1.6px dashed #cfc7ae;border-radius:12px;padding:10px 14px;margin:10px 0;font-size:.9rem}
.related{font-size:.82rem;color:#5a6a78;margin:8px 0 0}
.qbar{display:flex;gap:8px;align-items:center;flex-wrap:wrap;margin:6px 0}
.qbar .note{font-size:.84rem;color:#5a6a78}

/* syllabus mapping + comparison */
.tools{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:0 0 12px}
.search{flex:1 1 280px;font:inherit;border:1.6px solid var(--line);border-radius:999px;padding:9px 16px;background:#fff;min-width:0}
.search:focus{outline:none;border-color:var(--blue);box-shadow:0 0 0 3px var(--blue-soft)}
.chips{display:flex;gap:6px;flex-wrap:wrap;margin:0 0 12px}
.chips .chip-btn{font-size:.8rem;padding:5px 11px}
.legend{font-size:.88rem;color:#2f5a86;background:#dbe7f5;border:1px solid #a9c3e0;border-radius:10px;padding:10px 14px;margin:0 0 14px}
.legend p{margin:4px 0}
table.cmp{table-layout:fixed;min-width:860px}
table.cmp th{line-height:1.3}
table.cmp th.c-area{width:16%}
table.cmp th.c-diff{width:28%}
table.cmp td.col-mine,table.cmp th.col-mine{background:#eef5fd}
table.cmp th.col-mine{background:var(--blue-soft);color:var(--navy-deep)}
tr.area-row td{background:var(--navy);color:#fff;font-weight:800;letter-spacing:.02em}
.oid{font:inherit;font-weight:800;font-size:.86rem;color:var(--blue);background:#fff;border:1.4px solid #c9d7e6;border-radius:6px;padding:1px 7px;margin:0 4px 4px 0;cursor:pointer}
.oid:hover,.oid[aria-expanded="true"]{background:var(--blue-soft)}
.none{font-size:.8rem;font-weight:700;color:#8a3b30;background:#fdf1f0;border:1px dashed #e0b3ab;border-radius:6px;padding:2px 8px;display:inline-block}
.otext{font-size:.84rem;line-height:1.5;background:#fffdf6;border:1px solid #ece7d8;border-radius:8px;padding:8px 10px;margin:4px 0}
.otext .pg{display:block;font-size:.72rem;color:#7a8896;margin-top:4px}
.otext ul{margin:4px 0;padding-left:18px}
.hl{background:#ffe9a8;border-radius:3px}
.count{font-size:.86rem;color:var(--ink-soft);margin:0 0 8px}
.rowcard-lab{display:none}
.lv-cell{margin-bottom:6px}
@media (max-width:860px){
  table.cmp{min-width:0;table-layout:auto}
  table.cmp thead{display:none}
  table.cmp,table.cmp tbody,table.cmp tr,table.cmp td{display:block;width:100%}
  table.cmp tr.crow{border:1px solid #e0dccd;border-radius:10px;margin:0 0 10px;background:#fff;overflow:hidden}
  table.cmp td{border:none;border-top:1px solid #f0ecdf}
  table.cmp td:first-child{border-top:none}
  .rowcard-lab{display:block;font-size:.7rem;font-weight:800;letter-spacing:.05em;text-transform:uppercase;color:#7a8896;margin-bottom:3px}
  tr.area-row td{border-radius:8px;margin-top:6px}
}

/* landing */
.hero{display:flex;gap:18px;align-items:center;flex-wrap:wrap}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(290px,1fr));gap:18px;margin:0 0 24px}
a.card,.card{display:flex;flex-direction:column;gap:8px;background:var(--paper);border-radius:var(--radius);box-shadow:var(--card-shadow);border:1.6px solid transparent;padding:20px 22px;text-decoration:none;color:var(--ink)}
a.card:hover,a.card:focus-visible{border-color:var(--blue);transform:translateY(-1px)}
.card h3{margin:0;color:var(--navy-deep);font-size:1.18rem}
.card p{margin:0;color:var(--ink-soft);font-size:.94rem;line-height:1.5}
.card .stats{display:flex;gap:6px;flex-wrap:wrap;margin-top:4px}
.card .stats span{font-size:.76rem;font-weight:800;border:1px solid #d8d2c2;border-radius:999px;padding:2px 9px;background:#f8f6ef;color:#5a6a78}
.card .go{margin-top:auto;font-weight:800;color:var(--blue)}
.card.soon{opacity:.8;border:1.6px dashed #cfc7ae;box-shadow:none;background:#fbfaf6}
.topics{display:flex;gap:7px;flex-wrap:wrap;list-style:none;padding:0;margin:8px 0 0}
.topics li{font-size:.84rem;font-weight:700;color:#7a8896;border:1.6px dashed #cfc7ae;border-radius:999px;padding:5px 12px;background:#fbfaf6}
.status td:first-child{font-weight:700;white-space:nowrap}

/* lightbox for TYS source diagrams */
.lb{position:fixed;inset:0;z-index:2000;background:rgba(8,10,14,.85);display:flex;align-items:center;justify-content:center;padding:18px}
.lb[hidden]{display:none}
.lb img{max-width:96vw;max-height:90vh;background:#fff;border-radius:8px}
.lb button{position:absolute;top:14px;right:14px;font:700 15px/1 system-ui;cursor:pointer;color:var(--gold);background:#12171f;border:2px solid var(--frame-dark);padding:8px 12px}

@media (max-width:700px){html{scroll-padding-top:calc(var(--bar-h) + 10px)}.concept{scroll-margin-top:calc(var(--bar-h) + 10px)}.tabs{position:static}.fs-btn,.pn-btn{display:none}}
@media (max-width:640px){
  .doc{padding:18px 14px 80px}
  .panel{padding:18px 16px}
  .doc h1{font-size:1.6rem}
  .tablist button{padding:7px 11px;font-size:.84rem}
  summary .sum-end{margin-left:0}
}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}

/* ---------------- chem-style bar extras ---------------- */
html[data-ix="off"] .ix{display:none!important}
.content-main{text-decoration:none;border-right-width:1px}
.content-btn.content-arrow{border-left-width:0;padding-left:6px;padding-right:6px;gap:0}
.ix-wrap{display:inline-flex;align-items:center;gap:7px;font-family:var(--pixel);font-size:9px;letter-spacing:.04em;text-transform:uppercase;color:var(--gold);background:rgba(217,164,65,.12);border:2px solid var(--frame-dark);padding:4px 7px;cursor:pointer;white-space:nowrap}
.ix-wrap:hover{background:rgba(217,164,65,.3)}
.ix-wrap input{accent-color:var(--gold);width:13px;height:13px;cursor:pointer;margin:0}
.edit-wrap{display:inline-flex;align-items:center;gap:6px}
.edit-wrap[hidden],.edit-btn[hidden],.edit-tag[hidden]{display:none}
.edit-btn{font-size:9px;letter-spacing:.04em;text-transform:uppercase;cursor:pointer;color:var(--gold);background:rgba(217,164,65,.12);border:2px solid var(--frame-dark);padding:5px 7px;display:inline-flex;align-items:center;gap:4px;white-space:nowrap;font-family:var(--pixel)}
.edit-btn:hover,.edit-btn:focus-visible{background:var(--gold);color:#3a2c08}
.edit-tag{font-family:var(--pixel);font-size:9px;letter-spacing:.05em;text-transform:uppercase;color:#3a2c08;background:var(--gold);border-radius:999px;padding:3px 8px}
.fm-btn{font-family:var(--pixel);font-size:9px;letter-spacing:.04em;text-transform:uppercase;cursor:pointer;color:var(--gold);background:rgba(217,164,65,.12);border:2px solid var(--frame-dark);padding:5px 8px;display:inline-flex;align-items:center;gap:5px;white-space:nowrap}
.fm-btn:hover{background:var(--gold);color:#3a2c08}
.vid-wrap .vid-btn .vid-l,.fm-l{white-space:nowrap}
@media (max-width:1380px){.ix-label{display:none}}
@media (max-width:1100px){.fm-l{display:none}}
.defs .defs-box{width:min(760px,96vw);max-height:90vh;display:flex;flex-direction:column;background:var(--cream);border:3px solid var(--gold);border-radius:10px;overflow:hidden}
.defs-head{display:flex;gap:10px;align-items:center;justify-content:space-between;padding:10px 14px;background:var(--paper);border-bottom:2px solid var(--line)}
.defs-head b{color:var(--navy-deep)}
.defs-body{overflow:auto;padding:6px 16px 16px}
.edit-field{margin:10px 0}
.edit-field label{display:block;font-size:.8rem;font-weight:800;color:var(--ink-soft);margin:0 0 3px}
.edit-field textarea{width:100%;font:inherit;font-size:.92rem;padding:9px 11px;border:1.6px solid var(--amber);border-radius:10px;background:#fffdf6;min-height:90px;resize:vertical}
body.editing .concept{outline:3px dashed var(--amber);outline-offset:3px}
.edit-note{background:#fff8e8;border-left:4px solid var(--amber);border-radius:8px;padding:8px 14px;margin:0 0 14px;font-size:.9rem}

/* ---------------- TYS question tiles (box format; the open one spans the row) ---------------- */
.qgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:10px;margin:10px 0 4px;align-items:stretch}
.qgrid>details.qrow{margin:0;min-width:0;transition:border-color .15s,box-shadow .15s,transform .15s}
.qgrid>details.qrow:not([open]):hover{border-color:var(--blue);transform:translateY(-1px);box-shadow:0 3px 10px rgba(43,57,71,.12)}
.qgrid>details.qrow[open]{grid-column:1/-1;order:-1}
.qgrid>.also{grid-column:1/-1}
details.qrow>summary.qtile{display:flex;flex-direction:column;align-items:stretch;gap:6px;height:100%;padding:11px 13px;position:relative}
details.qrow[open]>summary.qtile{height:auto}
.qtile::before{position:absolute;left:12px;top:13px}
.qtop{display:flex;align-items:center;gap:8px;flex-wrap:wrap;padding-left:16px}
.qno{font-weight:800;color:var(--blue);font-size:1.05rem}
.qpill{font-size:.66rem;font-weight:800;letter-spacing:.04em;text-transform:uppercase;border-radius:999px;padding:2px 9px;background:var(--blue-soft);color:var(--blue)}
.qsnip{font-weight:600;color:var(--navy);font-size:.95rem;line-height:1.4}
.qfoot{margin-top:auto;display:flex;justify-content:flex-end;gap:6px;align-items:center}
.qmk{font-size:.66rem;font-weight:800;letter-spacing:.04em;text-transform:uppercase;border-radius:999px;padding:2px 9px;background:#fdefcf;color:#8a5a00;white-space:nowrap}
.fignum{font-size:.78rem;font-weight:800;letter-spacing:.05em;color:#7a8896;text-align:center;margin:6px 0 0}
.fignum+figcaption{margin-top:2px}

/* ---------------- contents (chapter cards) ---------------- */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(290px,1fr));gap:18px;margin:0 0 24px}
a.card.ccard{flex-direction:row;gap:14px;align-items:flex-start}
.ccard .num{flex:none;min-width:38px;height:38px;padding:0 8px;display:inline-flex;align-items:center;justify-content:center;font-weight:800;color:#fff;background:var(--navy);border-radius:999px}
.ccard .txt{display:flex;flex-direction:column;gap:5px;min-width:0}
.ccard .txt b{font-size:1.1rem;line-height:1.3;color:var(--navy-deep)}
.ccard .txt small{font-size:.88rem;line-height:1.5;color:var(--ink-soft)}
.ccard .txt em{font-style:normal;font-weight:800;color:var(--blue);margin-top:2px}
.block{margin:0 0 6px}
.keybox.ext{background:#f6eefb;border-left-color:#8a4bb0}
.keybox.ext .badge{margin-bottom:6px}

/* phones: the enlarged source figure opens at about twice screen width and can be panned, so axis labels and small text are readable */
@media (max-width:700px){
  .lb{align-items:flex-start;justify-content:flex-start;overflow:auto;padding:56px 8px 18px;-webkit-overflow-scrolling:touch}
  .lb img{max-width:none;max-height:none;width:210vw;flex:none}
  .lb button{position:fixed}
}

/* ---------------- concept tabs (every tab visible, wrapping; one panel at a time) ---------------- */
.tabs{position:static;margin:14px 0 18px}
.tablist button{white-space:normal;text-align:left;line-height:1.25}
.tablist .tabnum{margin-right:6px}
.tabpanel.panel[hidden]{display:none}
.qno.tys{font-size:.78rem;font-weight:700;color:var(--ink-soft);letter-spacing:.01em}
.qdiff{font-size:.66rem;font-weight:800;letter-spacing:.04em;text-transform:uppercase;border-radius:999px;padding:2px 9px;white-space:nowrap}
.qdiff.easy{background:#e7f2e4;color:#2e6b34}
.qdiff.medium{background:#fdefcf;color:#8a5a00}
.qdiff.hard{background:#f3dede;color:#b23b30}
.qzcard{border:1.6px solid var(--line);border-radius:12px;background:#fff;padding:12px 16px;margin:10px 0}

/* ---- site logo + chapter arrows, as on the Chemistry and Physics notes (wide screens only, never printed) ---- */
.site-logo{display:none;position:fixed;left:18px;top:calc(var(--bar-h) + 38px);z-index:40;width:112px}
.site-logo img{width:100%;height:auto;display:block}
.chap-arrow{display:none;position:fixed;top:50%;transform:translateY(-50%);z-index:40;width:54px;height:54px;border-radius:50%;background:var(--paper);border:1.6px solid var(--line);box-shadow:0 4px 14px rgba(43,57,71,.14);color:var(--navy);text-decoration:none;font-size:34px;line-height:1;align-items:center;justify-content:center;font-family:Georgia,serif}
.chap-arrow[hidden]{display:none!important}
.chap-prev{left:22px}
.chap-next{right:22px}
.chap-arrow:hover,.chap-arrow:focus-visible{border-color:var(--blue);color:var(--blue);background:#fff}
@media (min-width:1280px){.site-logo{display:block}}
@media (min-width:1140px){.chap-arrow:not([hidden]){display:flex}}
.badge.prac{background:#e7f2e4;color:#2e6b34}

/* ---------------- chapter Syllabus tab (modelled on the Chemistry notes' Syllabus tab) ---------------- */
.syltabs{margin:14px 0 12px}
.syltablist{display:flex;gap:8px;flex-wrap:wrap;padding:0;margin:0;list-style:none}
.syltablist button{font:inherit;font-size:.92rem;font-weight:800;cursor:pointer;color:var(--navy);background:var(--paper);border:1.6px solid var(--line);border-radius:999px;padding:8px 16px;display:inline-flex;align-items:center;gap:8px;box-shadow:0 1px 3px rgba(43,57,71,.07)}
.syltablist button:hover{border-color:var(--blue)}
.syltablist button[aria-selected="true"]{background:var(--navy);color:#fff;border-color:var(--navy)}
.sylcount{display:inline-flex;align-items:center;justify-content:center;min-width:22px;height:20px;padding:0 6px;border-radius:999px;font-size:.76rem;font-weight:800;background:var(--blue-soft);color:var(--blue)}
.syltablist button[aria-selected="true"] .sylcount{background:rgba(255,255,255,.22);color:#fff}
.sylcount.none{background:#f3dede;color:#b23b30}
.syl-blurb{font-size:.9rem;color:#5a6a78;margin:0 0 10px}
.syl-none{background:#fdf1f0;border-left:4px solid #c0563a;border-radius:8px;padding:12px 15px;color:#8a3b30;font-size:.95rem}
.sylcmp{min-width:0;table-layout:fixed;font-size:.78rem;overflow-wrap:break-word}
.doc .sylcmp th,.doc .sylcmp td{padding:7px 9px}
.doc .sylcmp th{width:33.33%;line-height:1.3}
.sylband{display:block;font-size:.92rem;color:var(--navy)}
.sylno{font-weight:800;color:var(--blue);margin-right:4px;font-variant-numeric:tabular-nums}
.sylout{margin-bottom:8px}
.sylout ul{margin:3px 0;padding-left:16px}
.sylout li{margin:2px 0}
.sylcmp td.dash{text-align:center;background:#fafbfc;vertical-align:middle}
.sylcmp td.cell-only{background:#fff8e6}
.sylcmp th.col-mine{background:var(--blue-soft)}
.sylcmp tr.note-row td{background:#f7f5ee;font-size:.82rem;color:#4a5a69}
.sylcmp tr.area-row td{font-size:.84rem}
mark.diff{background:#ffe08a;color:inherit;border-radius:3px;padding:0 2px}
.only-tag{display:inline-block;font-size:.66rem;font-weight:800;letter-spacing:.04em;text-transform:uppercase;color:#8a5a00;background:#fdefcf;border-radius:999px;padding:2px 8px}
.fig svg{min-width:0}
.ixwrap{margin:18px 0 8px}
.ixframe{display:block;width:100%;border:1.6px solid #ece7d8;border-radius:14px;background:#fdfcf8}
@media print{.ixwrap{display:none}}
.ixbadge{margin-right:8px;background:#fdf0d8;color:#8a5a10;border:1px solid #e8a13c}
.wxrow summary .sum-main{font-weight:700}
.wxtip{background:#fdf0d8;border-left:4px solid #e8a13c;padding:8px 12px;border-radius:6px}
.wxfig{margin:8px 0}

/* SG Question Bank page: the bank fills the space under the bar and brings its own course pills. */
.doc.frame{max-width:none;margin:0;padding:0}
.sgq-frame{display:block;width:100%;height:calc(100vh - 46px);border:0}
body.sgq .band-wrap{display:none}