/* Rocky shore fieldwork · IB Biology · the practical page.
   Colour tokens in both versions (bright and dark); nothing writes a colour of its own. */
:root{
  --ink:#14171F; --ink2:#3D4453; --ink3:#5F677A;
  --paper:#FCFCFD; --surface:#F1F2F7; --rule:#DEE0EA; --page:#ECEEF3; --sheet:#FFFFFF;
  --sea:#0B6670; --sea-soft:#E1F1F2; --sea-ink:#0B5A63;
  --amber:#8F5310; --amber-soft:#FDF3E3; --amber-edge:#E8B473;
  --ok:#1D7A45; --ok-soft:#E3F4EA; --bad:#B42318; --bad-soft:#FDECEA;
  --barn:#6B6B6B; --green:#3E8E1E; --brown:#8A5A12; --limp:#B4472A; --temp:#B42318;
  --ib:#2E3A8C; --ib-soft:#E7E9F7;
  --serif:Spectral,Georgia,serif;
  --sans:"IBM Plex Sans",ui-sans-serif,system-ui,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,Menlo,monospace;
  --shadow:0 1px 2px rgba(20,23,31,.05),0 8px 24px -12px rgba(20,23,31,.18);
  color-scheme:light;
}
@media (prefers-color-scheme:dark){
  :root:not([data-theme="light"]){
    --ink:#E9EBF2; --ink2:#B4BACB; --ink3:#9AA2B6;
    --paper:#111319; --surface:#1A1D26; --rule:#2C303C; --page:#0B0D12; --sheet:#151820;
    --sea:#5FC2C9; --sea-soft:#0F2A2D; --sea-ink:#8ED8DD;
    --amber:#E8B473; --amber-soft:#2A2114; --amber-edge:#7A5A2A;
    --ok:#5FD08F; --ok-soft:#10261A; --bad:#FF8A80; --bad-soft:#2B1312;
    --barn:#C9C9C9; --green:#8FD16B; --brown:#E0A95B; --limp:#F0957C; --temp:#FF8A80;
    --ib:#9EA9F0; --ib-soft:#1D2240;
    --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px -12px rgba(0,0,0,.6);
    color-scheme:dark;
  }
}
:root[data-theme="dark"]{
  --ink:#E9EBF2; --ink2:#B4BACB; --ink3:#9AA2B6;
  --paper:#111319; --surface:#1A1D26; --rule:#2C303C; --page:#0B0D12; --sheet:#151820;
  --sea:#5FC2C9; --sea-soft:#0F2A2D; --sea-ink:#8ED8DD;
  --amber:#E8B473; --amber-soft:#2A2114; --amber-edge:#7A5A2A;
  --ok:#5FD08F; --ok-soft:#10261A; --bad:#FF8A80; --bad-soft:#2B1312;
  --barn:#C9C9C9; --green:#8FD16B; --brown:#E0A95B; --limp:#F0957C; --temp:#FF8A80;
  --ib:#9EA9F0; --ib-soft:#1D2240;
  --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px -12px rgba(0,0,0,.6);
  color-scheme:dark;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--page);color:var(--ink);font-family:var(--sans);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:var(--sea-ink)}
.top{max-width:1360px;margin:0 auto;padding:16px 22px 0}
.lessonbar{display:flex;flex-wrap:wrap;align-items:center;gap:6px 12px;margin:-4px 0 14px;font-size:13px;color:var(--ink2)}
.lessonbar[hidden]{display:none}
.lesson__who{font-weight:600;color:var(--ink)}
.lesson__say.is-no{color:var(--bad)}
.lesson__t{font-weight:600}
.lesson__out{font:500 12.5px/1 var(--sans);color:var(--ink3);background:none;border:0;padding:0;text-decoration:underline;cursor:pointer}
.lesson__msg{flex-basis:100%;color:var(--amber)}
.lesson__g{display:inline-flex;min-height:32px;align-items:center}
.upbar{display:flex;justify-content:space-between;align-items:center;gap:12px;margin:0 0 8px}
.upbtns{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}
.themebtn{font:500 12.5px/1 var(--sans);color:var(--ink2);background:var(--surface);border:1px solid var(--rule);border-radius:100px;padding:7px 12px;cursor:pointer}
.themebtn:hover,.themebtn:focus-visible{color:var(--ink);border-color:var(--ink3)}
/* the way back (14 Oct 2026, Daniel: pupils missed it): a solid pill in this site's own colours */
.up{display:inline-flex;align-items:center;flex:none;white-space:nowrap;min-height:34px;margin:0;padding:0 16px 0 13px;font:650 14px/1 var(--sans,Inter,system-ui,sans-serif);letter-spacing:0;text-transform:none;color:var(--paper);background:var(--sea);border:0;border-radius:999px;text-decoration:none;box-shadow:0 1px 2px rgba(0,0,0,.2)}
.up:hover,.up:focus-visible{background:var(--sea-ink);color:var(--paper);text-decoration:none}
.eyebrow{font:500 11.5px/1 var(--sans);letter-spacing:.15em;text-transform:uppercase;color:var(--sea-ink)}
h1{font-family:var(--serif);font-weight:600;font-size:clamp(1.7rem,3.2vw,2.2rem);line-height:1.1;letter-spacing:-.015em;margin:8px 0 0}
.by{margin:5px 0 0;font-size:14.5px;color:var(--ink2)}
.top-note{margin:4px 0 0}
.by-me{color:inherit;text-decoration:none;border-bottom:1px dotted currentColor}
.by-me:hover,.by-me:focus-visible{border-bottom-style:solid}

/* ---------- the parts as steps across the top: always in view, the one open stands out, the ones seen are ticked ---------- */
.partbar{position:sticky;top:0;z-index:30;margin-top:10px;background:color-mix(in srgb,var(--page) 88%,transparent);
  -webkit-backdrop-filter:saturate(1.4) blur(10px);backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid var(--rule);border-top:1px solid var(--rule)}
.partbar{display:flex;align-items:center}
.partbar .tabs{flex:1;min-width:0;max-width:1360px;margin:0 auto;padding:10px 22px;display:flex;gap:6px;overflow-x:auto;scrollbar-width:none;scroll-padding:0 22px}
/* the word bank: one list for every answer typed on the page */
.wbbtn{flex:none;margin-right:22px;font:600 13px/1 var(--sans);color:var(--sea-ink);background:var(--sheet);border:1.5px solid var(--sea);border-radius:100px;padding:8px 14px;cursor:pointer;white-space:nowrap}
.wbbtn[aria-expanded="true"]{background:var(--sea);color:#fff}
.wb{position:fixed;z-index:40;right:16px;top:calc(var(--bar-h,56px) + 32px);width:min(360px,calc(100vw - 32px));max-height:calc(100vh - var(--bar-h,56px) - 56px);overflow:auto;background:var(--sheet);border:1px solid var(--rule);border-radius:14px;box-shadow:0 18px 50px -12px rgba(0,0,0,.35);padding:12px 16px 14px}
.wb[hidden]{display:none}
.wb__top{display:flex;align-items:center;justify-content:space-between;font-size:16px}
.wb .note{margin:4px 0 6px}
.wb__g{font:700 11px/1.3 var(--sans);letter-spacing:.12em;text-transform:uppercase;color:var(--sea-ink);margin:10px 0 5px}
.wb__w{display:flex;flex-wrap:wrap;gap:5px;margin:0}
.wb__w span{font-size:13.5px;background:var(--surface);border:1px solid var(--rule);border-radius:100px;padding:3px 9px}
/* part 5: the chi-squared tables under the photograph, so the data and the map are seen together */
.stage-data{margin-top:10px;background:var(--sheet);border:1px solid var(--rule);border-radius:12px;padding:8px 12px 10px}
.stage-data[hidden]{display:none}
.stage-data .sd__h{font:700 11px/1.3 var(--sans);letter-spacing:.12em;text-transform:uppercase;color:var(--ink3);margin:6px 0 2px}
.stage-data table.data{margin:4px 0 6px;font-size:13px}
.stage-data table.data td,.stage-data table.data th{padding:3px 6px}
/* part 5 (12 Oct 2026, Daniel: the photo and the observed data "together", no scrolling): the observed and expected tables
   side by side, and a photo no taller than the screen leaves room for (same shape: 1600 × 1350) */
.stage-data.two:not([hidden]){display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:0 14px;align-items:start}
.stage-data .sd__k{grid-column:1/-1;margin:0;font-size:12px;color:var(--ink3)}
.stage.chi .photo{width:min(100%,calc((100vh - var(--bar-h,56px) - 16px - 270px) * 1600 / 1350));margin:0 auto}
.partbar .tabs::-webkit-scrollbar{display:none}
.partbar .tabs button{flex:none;display:inline-flex;align-items:center;gap:8px;font:600 13.5px/1 var(--sans);color:var(--ink2);background:none;border:0;border-radius:100px;padding:6px 12px 6px 6px;cursor:pointer;white-space:nowrap}
.partbar .tabs .n{display:inline-grid;place-items:center;width:26px;height:26px;border-radius:50%;background:var(--sheet);border:1.5px solid var(--rule);font:600 12px/1 var(--sans);color:var(--ink3)}
.partbar .tabs button:hover{color:var(--ink)}
.partbar .tabs button:hover .n{border-color:var(--sea)}
.partbar .tabs button.seen .n{background:var(--sea-soft);border-color:var(--sea);color:var(--sea-ink)}
.partbar .tabs button[aria-selected="true"]{background:var(--sea);color:#fff}
.partbar .tabs button[aria-selected="true"] .n{background:#fff;border-color:#fff;color:var(--sea)}
:root[data-theme="dark"] .partbar .tabs button[aria-selected="true"]{color:#0B1D1F}
@media (prefers-color-scheme:dark){ :root:not([data-theme="light"]) .partbar .tabs button[aria-selected="true"]{color:#0B1D1F} }

/* ---------- the photograph (left, for the parts that use it) and the panel of the open part ---------- */
.layout{max-width:1360px;margin:22px auto 0;padding:0 22px 60px;display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,1fr);gap:28px;align-items:start}
.layout>*{min-width:0}
.layout.nophoto{grid-template-columns:minmax(0,1fr)}
.layout.nophoto .stage{display:none}
.layout.nophoto .panel{width:100%;max-width:940px;margin:0 auto}
.stage{position:sticky;top:calc(var(--bar-h,56px) + 16px);margin:0}
.photo{position:relative;border-radius:14px;overflow:hidden;box-shadow:var(--shadow);background:#123}
.photo img{display:block;width:100%;height:auto}
.photo svg{position:absolute;inset:0;width:100%;height:100%}
.stage figcaption{margin-top:8px;font-size:12.5px;color:var(--ink3);line-height:1.45}
.stage figcaption a{color:var(--ink3)}
.panel{background:var(--sheet);border:1px solid var(--rule);border-radius:18px;box-shadow:var(--shadow);padding:26px 30px 28px}
.part{scroll-margin-top:calc(var(--bar-h,56px) + var(--stage-h,0px) + 16px)}
.partno{font:600 11.5px/1 var(--sans);letter-spacing:.14em;text-transform:uppercase;color:var(--sea-ink);margin:0 0 8px}
.partnav{display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap;margin-top:28px;padding-top:18px;border-top:1px solid var(--rule)}
.partnav button{font:600 14px/1.2 var(--sans);border-radius:10px;padding:11px 16px;cursor:pointer}
.partnav .back{color:var(--ink2);background:none;border:1px solid var(--rule)}
.partnav .next{margin-left:auto;color:#fff;background:var(--sea);border:1px solid var(--sea)}
:root[data-theme="dark"] .partnav .next{color:#0B1D1F}
@media (prefers-color-scheme:dark){ :root:not([data-theme="light"]) .partnav .next{color:#0B1D1F} }
.partnav button:hover,.partnav button:focus-visible{filter:brightness(1.08)}

/* overlay drawing (photo coordinates 1600 x 1350) */
.ov text{font-family:var(--sans);paint-order:stroke;stroke:rgba(0,0,0,.72);stroke-width:7px;stroke-linejoin:round}
.ov .lab{fill:#fff;font-size:40px;font-weight:600}
.ov .lab.big{font-size:58px;font-weight:700}
.ov .lab-s{fill:#fff;font-size:34px;font-weight:600}
.ov .lab-xs{fill:#fff;font-size:24px;font-weight:600}
.ov .tape{stroke:#FFD43B;stroke-width:9;stroke-linecap:round}
.ov .tape-edge{stroke:rgba(0,0,0,.55);stroke-width:15;stroke-linecap:round}
.ov .q{fill:rgba(255,255,255,.12);stroke:#fff;stroke-width:5}
.ov .q.on{fill:rgba(255,212,59,.35);stroke:#FFD43B;stroke-width:7}
.ov .q.done{fill:rgba(31,160,90,.35);stroke:#7CF2AE}
.ov .stn{cursor:pointer}
.ov .stn circle{fill:#fff;stroke:#0B2B2F;stroke-width:5}
.ov .stn text{fill:#0B2B2F;stroke:none;font-size:30px;font-weight:700;text-anchor:middle;dominant-baseline:central}
.ov .stn.done circle{fill:#7CF2AE}
.ov .stn:hover circle,.ov .stn:focus-visible circle{fill:#FFD43B}
.ov .stn:focus{outline:none}
.ov .leader{stroke:#fff;stroke-width:4}
.ov .zone{fill:none;stroke:#fff;stroke-width:4;stroke-dasharray:14 10}
.ov .area{fill:none;stroke:#FF6B6B;stroke-width:7}
.ov .cell{fill:none;stroke:rgba(255,255,255,.45);stroke-width:2}
.ov .cell.pick{fill:rgba(255,212,59,.45);stroke:#FFD43B;stroke-width:4}
.ov .cell.seen{fill:rgba(124,242,174,.35);stroke:#7CF2AE;stroke-width:3}
.ov .pt{fill:#FFD43B;stroke:#0B2B2F;stroke-width:3}
.ov .scale{stroke:#fff;stroke-width:8}
.ov .zline{stroke:#fff;stroke-width:4;stroke-dasharray:18 12;opacity:.85}
/* the random area, zoomed in (parts 4, 5 and 8): about twice as large, so the words are smaller in the viewBox */
.ov .catcell{fill-opacity:.62;stroke-width:3}
.ov .lab-cat,.ov .lab-cnt,.ov .lab-pool{text-anchor:middle;dominant-baseline:central;font-weight:700;fill:#fff;stroke:rgba(0,0,0,.6);stroke-width:5px;paint-order:stroke}
.ov .lab-cat{font-size:17px}
.ov .lab-cat.dark{fill:#1F2937;stroke:rgba(255,255,255,.7)}
.ov .cntcell{fill:rgba(255,255,255,.14);stroke:rgba(255,255,255,.55);stroke-width:2}
.ov .cntcell.some{fill:rgba(255,212,59,.42);stroke:#FFD43B;stroke-width:3}
.ov .lab-cnt{font-size:24px}
.ov .lab-cnt.zero{fill:rgba(255,255,255,.75);font-weight:500}
.ov .lab-pool{font-size:14px;font-weight:600;fill:#BFE9FF}
.ov.zoomed .lab{font-size:28px}
.ov.zoomed .lab.big{font-size:36px}
.ov.zoomed .lab-s{font-size:22px}
.ov.zoomed .lab-xs{font-size:18px}
.ov.zoomed text{stroke-width:5px}
.ov.zoomed .scale{stroke-width:6}

/* ---------- parts: one open at a time ---------- */
.part{display:none}
.part.open{display:block}
.part h2{font-family:var(--serif);font-weight:600;font-size:1.65rem;line-height:1.2;margin:0 0 6px}
.part .sub{margin:0 0 14px;color:var(--ink2)}
.part h3{font:700 15px/1.3 var(--sans);margin:20px 0 6px}
.part p{margin:8px 0}
.part ul,.part ol{margin:8px 0;padding-left:22px}
.part li{margin:4px 0}
u{text-decoration-thickness:2px;text-underline-offset:3px;text-decoration-color:var(--sea)}
.statement{font:500 12px/1 var(--mono);color:var(--ink3);letter-spacing:.04em}

.box{border:1px solid var(--rule);border-radius:11px;padding:14px 16px;margin:12px 0;background:var(--surface)}
.box.sea{background:var(--sea-soft);border-color:transparent}
.box.amber{background:var(--amber-soft);border-color:var(--amber-edge)}
.box.ib{background:var(--ib-soft);border-color:transparent}
.box .k{font:700 11px/1 var(--sans);letter-spacing:.12em;text-transform:uppercase;color:var(--ink3);margin-bottom:7px}
.box.sea .k{color:var(--sea-ink)} .box.amber .k{color:var(--amber)} .box.ib .k{color:var(--ib)}

/* choices that redraw the photograph */
.choices{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin:12px 0}
.choices button{text-align:left;font:600 14.5px/1.3 var(--sans);color:var(--ink);background:var(--surface);border:1px solid var(--rule);border-radius:10px;padding:11px 13px;cursor:pointer}
.choices button small{display:block;font-weight:400;color:var(--ink3);font-size:12.5px;margin-top:3px}
.choices button[aria-pressed="true"]{border:2px solid var(--sea);background:var(--sea-soft);padding:10px 12px}
.choice-text{min-height:120px}

/* words that open their meaning in place */
.term{border:0;background:none;padding:0;font:inherit;color:inherit;border-bottom:2px dotted var(--sea);cursor:help}
.term[aria-expanded="true"]{background:var(--sea-soft)}
.def{display:block;margin:6px 0 8px;padding:9px 12px;border-left:3px solid var(--sea);background:var(--sea-soft);border-radius:0 8px 8px 0;font-size:15px}

/* a method's record, strength and weakness, each in its own colour */
.facts{display:grid;gap:8px;margin:10px 0 4px}
.fact{border-radius:10px;padding:9px 13px 10px;border:1px solid var(--rule);background:var(--sheet);font-size:15px;line-height:1.5}
.fact .fk{display:block;font:700 11px/1.3 var(--sans);letter-spacing:.12em;text-transform:uppercase;margin-bottom:3px;color:var(--ink3)}
.fact.pro{background:var(--ok-soft);border-color:transparent;border-left:4px solid var(--ok)}
.fact.pro .fk{color:var(--ok)}
.fact.con{background:var(--amber-soft);border-color:transparent;border-left:4px solid var(--amber-edge)}
.fact.con .fk{color:var(--amber)}
.fact.rec{border-left:4px solid var(--sea)}
.fact.rec .fk{color:var(--sea-ink)}
@media (min-width:1180px){ .facts{grid-template-columns:1fr 1fr} .fact.rec{grid-column:1/-1} }

/* a quick check after each piece of theory */
.qc{margin:14px 0 18px;padding:12px 16px 6px;border:1px solid var(--rule);border-left:4px solid var(--sea);border-radius:0 12px 12px 0;background:var(--sheet)}
.fold-in .qc{background:var(--surface)}
.qc__k{font:700 11px/1.3 var(--sans);letter-spacing:.12em;text-transform:uppercase;color:var(--sea-ink);margin-bottom:5px}
.qc__k::before{content:'?';display:inline-grid;place-items:center;width:17px;height:17px;margin-right:7px;border-radius:50%;background:var(--sea);color:var(--paper);font-size:11px;letter-spacing:0;vertical-align:1px}
.qc__q{margin:0 0 8px;font-weight:500}
.qc__row{display:flex;flex-wrap:wrap;align-items:center;gap:6px}
.qc__row .gapin{font-size:15.5px;padding:8px 10px}
.qc__row .btn{margin:0}
.qc__u{font-weight:600;color:var(--ink2);margin-right:4px}
.qc .opts{margin-top:4px}
.qc>p:last-child{margin:8px 0 8px}
.gate[hidden]{display:none}

/* chi-squared: the four groups, in the same colours on the photograph and in the tables */
.catkey{display:flex;flex-wrap:wrap;gap:6px 14px;margin:6px 0 4px;font-size:13.5px;color:var(--ink2)}
.catk{display:inline-flex;align-items:center;gap:6px}
.catk i{width:14px;height:14px;border-radius:4px;flex:none;box-shadow:inset 0 0 0 1px rgba(0,0,0,.15)}
.catk b{font-weight:700;color:var(--ink)}
table.data td.cat{position:relative;font-weight:600}
table.data td.cat::before{content:'';position:absolute;left:0;top:0;bottom:0;width:5px}
table.data td.c-yy::before{background:#8B5CF6} table.data td.c-yn::before{background:#F97316}
table.data td.c-ny::before{background:#22C55E} table.data td.c-nn::before{background:#9CA3AF}

/* part 10: the animals of the real shore, each with its photographs beside its description */
.ids{display:grid;gap:10px;margin:10px 0 8px}
.idc{display:grid;grid-template-columns:auto minmax(0,1fr);gap:14px;align-items:start;background:var(--sheet);border:1px solid var(--rule);border-radius:12px;padding:12px}
.idc__pics{display:flex;gap:6px}
.idc__pics a{display:block;line-height:0;border-radius:9px;overflow:hidden}
.idc__pics img{width:140px;height:140px;object-fit:cover}
.idc__pics a:hover img,.idc__pics a:focus-visible img{filter:brightness(1.08)}
.idc__t b{font-size:16px}
.idc__t i{color:var(--ink2);margin-left:4px}
.idc__t p{margin:5px 0 0;font-size:15px}
table.measure td,table.measure th{vertical-align:top}
/* part 10 in two blocks: what to learn (with its quick checks), then a differently coloured panel for the day itself */
.blk{font:700 11.5px/1.3 var(--sans);letter-spacing:.14em;text-transform:uppercase;color:var(--sea-ink);margin:22px 0 2px;padding-top:12px;border-top:2px solid var(--sea)}
.getready{margin:26px -8px 12px;padding:4px 18px 16px;border-radius:16px;background:var(--amber-soft);border:1px solid var(--amber-edge)}
.getready .blk{color:var(--amber);border-top-color:var(--amber-edge)}
.getready .box{background:var(--sheet)}
.getready ul.kit{list-style:none;margin:8px 0 14px;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(190px,1fr));gap:8px}
.kit__i{display:flex;align-items:center;gap:12px;background:var(--sheet);border:1px solid var(--rule);border-radius:12px;padding:10px 12px}
.kit__i img{width:52px;height:52px;flex:none}
.kit__i span{font-size:13.5px;line-height:1.4;color:var(--ink2)}
.kit__i b{display:block;font-size:15px;color:var(--ink);margin-bottom:1px}
@media (max-width:560px){ .getready{margin:22px -6px 12px;padding:4px 12px 12px} }
@media (max-width:560px){
  .idc{grid-template-columns:1fr}
  .idc__pics a{flex:1}
  .idc__pics img{width:100%;height:auto;aspect-ratio:1}
}
.words{display:flex;flex-wrap:wrap;gap:6px;margin:8px 0}
.words .term{border:1px solid var(--rule);border-radius:100px;padding:5px 11px;background:var(--surface);font-size:14px}

/* tables */
table.data{border-collapse:collapse;width:100%;font-size:14px;margin:10px 0}
table.data th,table.data td{border:1px solid var(--rule);padding:5px 7px;text-align:center}
table.data th{background:var(--surface);font-weight:600;font-size:12.5px;line-height:1.25}
table.data td.l{text-align:left}
table.data tr.cur td{background:var(--sea-soft)}
table.data td.miss{color:var(--ink3)}
.tablewrap{overflow-x:auto}

/* buttons */
.btn{display:inline-block;font:600 14px/1 var(--sans);color:var(--paper);background:var(--sea);border:0;border-radius:9px;padding:11px 16px;cursor:pointer;text-decoration:none;margin:4px 6px 4px 0}
.btn.ghost{color:var(--sea-ink);background:transparent;border:1px solid var(--sea)}
.btn:hover,.btn:focus-visible{filter:brightness(1.1)}
.btn[disabled]{opacity:.45;cursor:default}
.note{font-size:13.5px;color:var(--ink3)}
.ok{color:var(--ok);font-weight:600} .bad{color:var(--bad);font-weight:600}

/* steps of a calculation, one at a time */
.steps{display:flex;flex-wrap:wrap;gap:5px;margin:10px 0 12px}
.steps button{font:600 12.5px/1 var(--sans);border:1px solid var(--rule);background:var(--surface);color:var(--ink3);border-radius:7px;padding:7px 9px;cursor:pointer}
.steps button.done{color:var(--sea-ink);border-color:var(--sea)}
.steps button.now{background:var(--sea);border-color:var(--sea);color:var(--paper)}
.stepbody{min-height:150px}
.formula{font-family:var(--mono);font-size:14.5px;background:var(--surface);border:1px solid var(--rule);border-radius:8px;padding:9px 12px;margin:8px 0;overflow-x:auto;white-space:nowrap}
kbd{font-family:var(--mono);font-size:13px;background:var(--surface);border:1px solid var(--rule);border-radius:5px;padding:1px 5px}

/* the quadrat window */
dialog.quad{border:0;border-radius:14px;padding:0;max-width:1100px;width:calc(100% - 24px);background:var(--paper);color:var(--ink);box-shadow:0 20px 60px rgba(0,0,0,.45)}
dialog.quad::backdrop{background:rgba(8,14,20,.72)}
.quad-in{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(0,1fr);gap:20px;padding:18px}
.quad-img{position:relative}
.quad-img img{display:block;width:100%;height:auto;border-radius:8px}
/* the quadrat diagram and what a pupil presses on it (12 Oct 2026) */
.quad-pic{min-height:200px}
.quad-pic svg{display:block;width:100%;height:auto;border-radius:10px;touch-action:manipulation;user-select:none;-webkit-user-select:none}
.quad-pic .q-weed{transition:opacity .25s}
.quad-pic svg.lifted .q-weed{opacity:.1}
.qstrings line{stroke:#1E1E1E;stroke-opacity:.72;stroke-width:4;stroke-linecap:round}
.qkeyr{stroke:#111;stroke-width:6;stroke-dasharray:16 10}
.qhit{fill:#fff;fill-opacity:0;cursor:pointer}
.qhit:hover{fill-opacity:.25;stroke:#fff;stroke-width:3}
.qbadge{fill:var(--sea);stroke:#fff;stroke-width:4;pointer-events:none}
.qbadge-t{fill:#fff;font:700 22px/1 var(--sans);text-anchor:middle;dominant-baseline:central;pointer-events:none}
.qring{fill:none;stroke:#FFD43B;stroke-width:7;stroke-dasharray:14 9;pointer-events:none}
.quad-how{font-size:14.5px;line-height:1.5;margin:6px 0 4px}
.qsp,.qgreen{display:flex;flex-wrap:wrap;gap:6px;margin:8px 0 4px;align-items:center}
.qsp button,.qgreen button{display:inline-flex;align-items:center;gap:7px;font:600 13.5px/1 var(--sans);color:var(--ink);background:var(--surface);border:1px solid var(--rule);border-radius:9px;padding:9px 11px;cursor:pointer}
.qsp button[aria-pressed="true"],.qgreen button[aria-pressed="true"]{border:2px solid var(--sea);background:var(--sea-soft);padding:8px 10px}
.qsp__n{font-weight:700;color:var(--sea-ink);margin-left:2px}
.qgreen span{font-size:14px;color:var(--ink2);margin-right:2px}
.qcount{font-size:15px;margin:8px 0 2px}
.qcount b{font-size:18px;color:var(--sea-ink)}
.qkey__h{font:700 11px/1 var(--sans);letter-spacing:.12em;text-transform:uppercase;color:var(--ink3);margin:16px 0 6px}
.qkey{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(160px,1fr));gap:6px}
.qkey li{display:flex;gap:9px;align-items:center;font-size:12.5px;line-height:1.35;color:var(--ink2)}
.qkey svg{width:40px;height:40px;flex:none;border-radius:7px}
.qkey b{display:block;font-size:13.5px;color:var(--ink)}
.quad-img .tag{position:absolute;left:10px;top:10px;background:rgba(0,0,0,.65);color:#fff;font:600 13px/1 var(--sans);padding:6px 9px;border-radius:6px}
.quad h2{font-family:var(--serif);font-size:1.4rem;margin:0 0 4px}
.quad .row{display:grid;grid-template-columns:1fr 92px 70px;gap:8px;align-items:center;margin:7px 0}
.quad .row label{font-size:14.5px}
.quad .row input,.quad .row select{font:500 15px/1 var(--sans);padding:7px 8px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink);width:100%}
.quad .row .key{font-size:13px;color:var(--ink3)}
.sw{display:inline-block;width:11px;height:11px;border-radius:3px;margin-right:6px;vertical-align:-1px}
.close-x{float:right;border:0;background:var(--surface);color:var(--ink);font-size:20px;line-height:1;border-radius:8px;padding:6px 10px;cursor:pointer}

/* graphs drawn on the page */
.chart{width:100%;height:auto;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.chart text{font-family:var(--sans);fill:var(--ink2);font-size:13px}
.chart .ax{stroke:var(--ink3);stroke-width:1.2}
.chart .gr{stroke:var(--rule);stroke-width:1}
.chart .pt{stroke:var(--paper);stroke-width:1.5}
.chart .fit{stroke-width:2;stroke-dasharray:6 5}

/* downloads */
a.card{display:block;text-decoration:none;color:inherit;background:var(--surface);border:1px solid var(--rule);border-radius:11px;padding:13px 16px;margin:10px 0}
a.card:hover,a.card:focus-visible{border-color:var(--sea);box-shadow:var(--shadow);outline:none}
a.card .t{font-weight:600}
a.card .d{font-size:14px;color:var(--ink2);margin-top:3px}
.check li{list-style:none;margin-left:-20px;padding-left:26px;position:relative}
.check li::before{content:"";position:absolute;left:2px;top:5px;width:13px;height:13px;border:2px solid var(--sea);border-radius:3px}

/* practice: gaps, frames, answers */
input.gapin{font:600 14.5px/1.2 var(--sans);color:var(--ink);background:var(--paper);border:1.5px solid var(--sea);border-radius:7px;padding:4px 7px;margin:2px 2px;max-width:100%;width:auto}
input.gapin:focus{outline:2px solid var(--sea);outline-offset:1px}
input.gapin.right{border-color:var(--ok);background:var(--ok-soft)}
input.gapin.wrong{border-color:var(--bad);background:var(--bad-soft)}
.ans{font:600 13px/1.2 var(--sans);color:var(--ok);margin:0 4px}
.ans::before{content:'→ '}
.opts{display:grid;gap:8px;margin:10px 0 6px}
.opt{display:flex;gap:12px;align-items:flex-start;width:100%;text-align:left;font:500 15px/1.45 var(--sans);color:var(--ink);background:var(--sheet);border:1px solid var(--rule);border-radius:10px;padding:10px 14px;cursor:pointer}
.opt:hover,.opt:focus-visible{border-color:var(--sea)}
.opt__l{flex:none;display:inline-grid;place-items:center;width:24px;height:24px;margin-top:-1px;border-radius:50%;border:1.5px solid var(--rule);font:600 12px/1 var(--sans);color:var(--ink3)}
.opt.chosen-wrong{border-color:var(--bad);background:var(--bad-soft)}
.opt.chosen-wrong .opt__l{border-color:var(--bad);color:var(--bad)}
.opt.chosen-right{border-color:var(--ok);background:var(--ok-soft)}
.opt.chosen-right .opt__l{border-color:var(--ok);background:var(--ok);color:#fff}
.mrow{margin:9px 0;line-height:2.1}
.frame-s{line-height:2.25;font-size:15.5px}
.box.frame{background:var(--paper)}
textarea{width:100%;font:15px/1.5 var(--sans);color:var(--ink);background:var(--paper);border:1px solid var(--rule);border-radius:8px;padding:9px 11px;margin:6px 0}
label.tick{display:block;margin:4px 0;font-size:14.5px}
pre.code{font:13px/1.5 var(--mono);background:#0F1C20;color:#E6F4F1;border-radius:8px;padding:10px 12px;overflow-x:auto;margin:8px 0}
pre.code.out{background:var(--surface);color:var(--ink2);border:1px solid var(--rule)}
code{font-family:var(--mono);font-size:.92em}
.numin{font:600 15px/1 var(--sans);width:120px;padding:8px 9px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink);margin-right:6px}
.linkish{border:0;background:none;padding:0;font:inherit;color:var(--sea-ink);text-decoration:underline;cursor:pointer}
summary{cursor:pointer}
footer{max-width:1360px;margin:0 auto;padding:18px 22px 50px;border-top:1px solid var(--rule);font-size:13px;color:var(--ink3)}
footer a{color:var(--ink3)}

@media (max-width:1000px){
  .layout{grid-template-columns:1fr}
  .stage{position:relative;top:0}
  .quad-in{grid-template-columns:1fr}
  .stage-data{display:none}
  .wbbtn{margin-right:12px;padding:7px 11px}
  /* parts that use the photograph keep it in view at the top of a phone or iPad screen, under the step bar */
  body.photo-on .stage{position:sticky;top:var(--bar-h,56px);z-index:6;background:var(--page);padding:8px 0;margin:0 -22px;padding-left:22px;padding-right:22px}
  body.photo-on .stage .photo{width:min(100%,calc(44vh * 1600 / 1350));margin:0 auto}
  body.photo-on .stage figcaption{display:none}
  .panel{padding:20px 18px 22px;border-radius:14px}
}
.fold{border:1px solid var(--rule);border-radius:12px;background:var(--sheet);margin:10px 0;scroll-margin-top:calc(var(--bar-h,56px) + var(--stage-h,0px) + 12px)}
.fold>summary{list-style:none;display:flex;gap:12px;align-items:baseline;padding:13px 16px;font:600 15.5px/1.35 var(--sans);color:var(--ink);cursor:pointer}
.fold>summary::-webkit-details-marker{display:none}
.fold>summary .fk{flex:none;min-width:86px;font:600 11px/1.4 var(--sans);letter-spacing:.1em;text-transform:uppercase;color:var(--sea-ink)}
.fold>summary .ft small{font-weight:500;font-size:12px;color:var(--ink3);margin-left:6px;white-space:nowrap}
.fold>summary::after{content:'+';margin-left:auto;padding-left:10px;font-weight:400;font-size:20px;line-height:1;color:var(--ink3)}
.fold[open]>summary::after{content:'−'}
.fold>summary:hover,.fold>summary:focus-visible{background:var(--surface);border-radius:12px}
.fold[open]>summary{border-bottom:1px solid var(--rule);border-radius:12px 12px 0 0}
.fold-in{padding:6px 16px 14px}
.fold-in>.quiz>h3:first-child,.fold-in>.practice>h3:first-child{display:none}
.fold-in>.quiz,.fold-in>.practice{margin:0}
#limp-list{white-space:normal;word-spacing:2px}
.qpick{display:flex;flex-wrap:wrap;gap:6px;margin:6px 0 14px}
.qpick button{font:600 14px/1 var(--sans);min-width:46px;padding:11px 8px;border-radius:9px;border:1px solid var(--rule);background:var(--surface);color:var(--ink);cursor:pointer}
.qpick button:hover,.qpick button:focus-visible{border-color:var(--sea)}
.qpick button.done{background:var(--ok-soft);border-color:var(--ok);color:var(--ok)}
@media (max-width:640px){
  .fold>summary{position:relative;flex-wrap:wrap;gap:3px 8px;padding:11px 38px 11px 13px}
  .fold>summary .fk{min-width:0;width:100%}
  .fold>summary::after{position:absolute;right:14px;top:13px}
  .fold-in{padding:6px 13px 12px}
  /* the photograph is narrow on a phone: bigger words and numbers on it */
  .ov text{stroke-width:11px}
  .ov .lab{font-size:66px}
  .ov .lab.big{font-size:84px}
  .ov .lab-s{font-size:56px}
  .ov .lab-xs{font-size:40px}
  .ov .stn text{font-size:46px}
}
@media (max-width:520px){
  #btnRestart .lg{display:none}
  .choices{grid-template-columns:1fr}
  .layout{padding:0 12px 50px}
  .panel{padding:18px 14px 20px}
  .partbar .tabs{padding:8px 12px}
  .quad .row{grid-template-columns:1fr 80px 62px}
}
@media print{
  .partbar,.stage,.btn,.partnav,dialog{display:none!important}
  .panel{border:0;box-shadow:none;padding:0}
  .part{display:block!important;break-inside:avoid}
  .layout{display:block}
}

/* progress in the part tabs (12 Oct 2026). The first try, a thin ring around the number, read as a broken circle (Daniel:
   "they look very ugly … they are cut … they don't really look like progression"). Now a bar under the part's name fills
   as its questions are done (this round); a part with every question done has a green circle. */
.partbar .tabs button{position:relative}
.partbar .tabs .pb{display:none;position:absolute;left:40px;right:12px;bottom:2px;height:3px;border-radius:2px;background:var(--rule);overflow:hidden}
.partbar .tabs .pb i{display:block;height:100%;width:calc(var(--p) * 1%);background:var(--sea);border-radius:2px}
.partbar .tabs button.prog .pb{display:block}
.partbar .tabs button[aria-selected="true"] .pb{background:rgba(255,255,255,.35)}
.partbar .tabs button[aria-selected="true"] .pb i{background:#fff}
.partbar .tabs button:not([aria-selected="true"]) .n.full{background:var(--ok);border-color:var(--ok);color:#fff}
/* "Your task" at the top of every part, with its tally */
.task{display:flex;gap:12px;align-items:flex-start;justify-content:space-between;background:var(--sea-soft);border-radius:12px;padding:10px 14px;margin:0 0 16px}
.task p{margin:2px 0 0;font-size:15px;line-height:1.45}
.task__k{font:700 11px/1.2 var(--sans);letter-spacing:.12em;text-transform:uppercase;color:var(--sea-ink)}
.task__n{flex:none;font:600 12.5px/1.2 var(--sans);color:var(--sea-ink);background:var(--sheet);border:1px solid var(--sea);border-radius:100px;padding:6px 10px;white-space:nowrap}
.task__n:empty{display:none}
.task__n.full{background:var(--ok);border-color:var(--ok);color:#fff}
/* part 3: one main button, the rest small */
.tbtns{margin:10px 0 4px}
.tlinks{margin:2px 0 8px;font-size:13.5px;color:var(--ink3)}
/* the quadrat window: a strip to move along the transect */
.qstrip{display:flex;flex-wrap:wrap;gap:4px;align-items:center;margin:4px 0 8px}
.qstrip button{min-width:30px;height:30px;font:600 12.5px/1 var(--sans);color:var(--ink2);background:var(--surface);border:1px solid var(--rule);border-radius:8px;cursor:pointer}
.qstrip button.done{background:var(--ok-soft);border-color:var(--ok);color:var(--ok)}
.qstrip button.cur{background:var(--sea);border-color:var(--sea);color:#fff}
.qstrip .note{margin-left:4px}
.qhit:focus{outline:none}
.qhit:focus-visible{fill:#fff;fill-opacity:.3;stroke:var(--sea);stroke-width:6}
@media (max-width:1000px){
  /* on a phone the drawing stays at the top of the window while the boxes are filled in */
  .quad-img{position:sticky;top:0;z-index:3;background:var(--paper);padding-bottom:6px}
  .task{flex-direction:column;gap:6px}
}