/* Shared task-first layout. Blue is reserved for actions and selected states. */
.tk-body{--tk-panel-gap:1.2rem;transition:none!important}
.tk-body .tk-main{line-height:1.7}
@media screen{html:not(.tb1-contrast-dark):not(.tb1-contrast-high) body.tk-body{background-color:var(--bg)!important;color:var(--t1)!important}}
.tk-lesson .tk-stats .tk-stat-ic{background:var(--tk-tint);color:var(--tk-tint-ink);box-shadow:none}
.tk-body .tk-main :is(button,a,input,select,summary):focus-visible{outline:3px solid var(--c-500);outline-offset:3px}
.tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts){gap:0;border:1px solid var(--bd);border-radius:var(--r);overflow:hidden;background:var(--bg-c);box-shadow:var(--sh)}
.tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat{border:0;border-radius:0;box-shadow:none;min-height:116px;align-content:start;padding:1.1rem;column-gap:.75rem}
.tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat+.tk-stat{border-left:1px solid var(--bd)}
.tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat-val{font-size:1.5rem;line-height:1.4}
.tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat-lbl{font-size:.81rem;line-height:1.6}
.tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat-sub{font-size:.76rem;line-height:1.7}
.tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat-ic{width:38px;height:38px;box-shadow:none}
.tk-lesson-context{display:flex;align-items:center;flex-wrap:wrap;gap:.35rem 1rem;margin:-.4rem 0 .8rem;padding:0 .25rem;color:var(--t2);font-size:.78rem;line-height:1.8}
.tk-lesson-context>span,.tk-lesson-context>a{display:inline-flex;align-items:center;gap:.4rem}
.tk-lesson-context>span>i{color:var(--c-500)}
.tk-lesson-context>a{min-height:32px;color:var(--tk-tint-ink);text-decoration:none}
.tk-lesson-context>a:hover{text-decoration:underline}
.tk-content-date{margin-left:auto}

/* Seven original lessons share this workbench; the two bespoke labs keep theirs. */
.tk-workbench .tk-lab-grid{display:block;margin-bottom:var(--tk-panel-gap)}
.tk-workbench .tk-lab-grid>.tk-card{margin-bottom:var(--tk-panel-gap)}
.tk-workbench #lbCard{display:grid;grid-template-columns:minmax(0,1fr) 310px;align-items:stretch}
.tk-workbench #lbCard>.tk-card-hd{grid-column:1/-1}
.tk-workbench #lbCard>:nth-child(2){grid-column:1;grid-row:2;min-width:0;align-self:center}
.tk-workbench #lbCard>.lb-dock{grid-column:2;grid-row:2;min-width:0;border-left:1px solid var(--bd);display:flex;flex-direction:column;background:var(--bg-m);z-index:auto}
.tk-workbench #lbCard .lb-toolbar{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.7rem;padding:1.1rem;border-top:0;background:transparent;align-items:center}
.tk-workbench .lb-toolbar>:is(div,label,span){grid-column:1/-1;min-width:0}
.tk-workbench .lb-toolbar>.tk-btn{min-width:0;min-height:44px;padding:.65rem .55rem;font-size:.84rem;line-height:1.5;white-space:normal}
.tk-workbench .lb-toolbar>.tk-btn-primary{grid-column:1/-1;min-height:48px}
.tk-workbench .lb-toolbar>.tk-btn:only-of-type{grid-column:1/-1}
.tk-workbench .tk-control-intro{padding-bottom:.25rem}
.tk-workbench .tk-control-intro h3{font:700 1rem/1.6 var(--f-b);color:var(--t1);margin:0 0 .25rem}
.tk-workbench .tk-control-intro p{font-size:.82rem;line-height:1.7;color:var(--t2);margin:0}
.tk-workbench .lb-toolbar>:is(.tm-ctl,.tf-ctl,.ev-ctl,.ys-ctl,.og-jump){display:grid;gap:.4rem;font-size:.82rem;color:var(--t2);margin:0}
.tk-workbench .lb-toolbar .tk-seg{display:grid;grid-template-columns:repeat(auto-fit,minmax(68px,1fr));width:100%;min-width:0}
.tk-workbench .lb-toolbar .tk-seg button{min-width:0;min-height:44px;white-space:normal;font-size:.79rem;line-height:1.5;padding:.35rem .4rem}
.tk-workbench .lb-toolbar .tk-seg button[aria-pressed="true"]{background:#1d4ed8;color:#fff}
.tk-workbench .lb-toolbar .ys-ctl .tk-seg,.tk-workbench .lb-toolbar .og-jump .tk-seg{grid-template-columns:repeat(2,minmax(0,1fr))}
.tk-workbench .lb-toolbar>#seriesBtn,.tk-workbench .lb-toolbar>#monthBtn{grid-column:1/-1}
.tk-workbench .lb-toolbar .tm-knobs{display:grid;grid-template-columns:1fr 1fr;gap:.5rem}
.tk-workbench .lb-toolbar .tm-knobs .tk-btn{width:100%;min-height:44px}
.tk-workbench .lb-toolbar .ev-stepper{display:flex;align-items:center;justify-content:space-between;min-width:0;gap:.5rem}
.tk-workbench .lb-toolbar .ev-stepper .tk-btn{min-width:44px;min-height:44px}
.tk-workbench .lb-toolbar .ys-range{display:grid;grid-template-columns:minmax(0,1fr) auto;white-space:normal;gap:.25rem .5rem;font-size:.82rem}
.tk-workbench .lb-toolbar .ys-range input{grid-row:2;grid-column:1/-1;width:100%;min-width:0;min-height:44px;margin:0}
.tk-workbench .lb-toolbar .ys-range output{grid-row:1;grid-column:2;min-width:0;font-size:.8rem}
.tk-workbench .lb-toolbar .tk-switch{min-height:44px;font-size:.82rem;line-height:1.6}
.tk-workbench .lb-toolbar .lb-gl-note{font-size:.76rem;line-height:1.7}
.tk-workbench .lb-toolbar .tk-control-field{padding:.8rem;border:1px solid var(--bd);border-radius:var(--rs);background:var(--bg-c)}
.tk-workbench .tk-control-field .lb-temp input{min-width:0;width:100%;min-height:44px}
.tk-workbench .tk-control-field .lb-temp output{font-size:1.15rem;min-width:3.8em}
.tk-workbench .tk-control-field p{font-size:.8rem;line-height:1.7;color:var(--t2)}
.tk-workbench #lbCard .lb-status{margin:0;margin-top:auto;min-height:100px;font-size:.81rem;line-height:1.8;padding:1rem 1.1rem;background:var(--bg-c);border-top:1px solid var(--bd);color:var(--t2)}
.tk-workbench .tk-lab-grid>.tk-model-panel{position:static;max-height:none;overflow:clip;box-shadow:var(--sh)}
.tk-workbench .tk-model-panel>.tk-fsheet{display:grid;grid-template-columns:repeat(var(--tk-model-cols,3),minmax(0,1fr))}
.tk-workbench .tk-model-panel .tk-frow{min-width:0;padding:1.2rem;border:0;border-bottom:1px solid var(--bd);border-right:1px solid var(--bd)}
.tk-workbench .tk-model-panel .tk-frow h3{color:var(--t1);font-size:.88rem;line-height:1.7;margin-bottom:.65rem}
.tk-workbench .tk-model-panel .tk-frow p{color:var(--t2);font-size:.84rem;line-height:1.8}
.tk-workbench .tk-model-panel .tk-math{font-size:.92rem;line-height:1.9;overflow-wrap:anywhere}
.tk-workbench .tk-model-panel .tk-math+.tk-math{margin:.5rem 0;padding:.6rem .75rem;border-radius:8px;background:var(--bg-m);font-size:.82rem}
.tk-model-help{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,280px),1fr))}
.tk-guide{min-width:0;padding:.35rem 1.2rem;border-right:1px solid var(--bd)}
.tk-guide>summary{cursor:pointer;min-height:44px;padding:.5rem 0;font:600 .84rem/1.8 var(--f-b);color:var(--t2)}
.tk-guide>summary i{color:var(--c-500);margin:0 .4rem}
.tk-guide-bd{padding:.5rem 0 1rem;line-height:1.8;font-size:.84rem}
.tk-workbench #lbCard:fullscreen,.tk-workbench #lbCard:-webkit-full-screen{display:grid;align-content:start}
.tk-workbench #lbCard:fullscreen>.lb-dock,.tk-workbench #lbCard:-webkit-full-screen>.lb-dock{max-height:calc(100dvh - 78px);overflow:auto}
.tk-workbench #lbCard:fullscreen>:nth-child(2),.tk-workbench #lbCard:-webkit-full-screen>:nth-child(2){max-width:100%;margin:auto}

/* Secondary explanations and practice use the same accessible native disclosure. */
.tk-lesson .tk-disclosure{overflow:clip}
.tk-disclosure-hd{display:block;list-style:none;cursor:pointer;padding:1rem 1.2rem;transition:background-color .2s}
.tk-disclosure-hd::-webkit-details-marker{display:none}
.tk-disclosure-hd:hover{background:var(--bg-m)}
.tk-disclosure-hd h2{display:flex;align-items:center;gap:.7rem;min-height:44px;margin:0;color:var(--t1);font:600 1rem/1.6 var(--f-d)}
.tk-disclosure-hint{margin-left:auto;font:400 .8rem/1.6 var(--f-b);color:var(--t2);white-space:nowrap}
.tk-disclosure-arrow{flex:none;margin-left:.25rem;font-size:.8rem;color:var(--c-500);transition:transform .2s}
.tk-disclosure[open]>.tk-disclosure-hd{border-bottom:1px solid var(--bd)}
.tk-disclosure[open]>.tk-disclosure-hd .tk-disclosure-hint{display:none}
.tk-disclosure[open]>.tk-disclosure-hd .tk-disclosure-arrow{transform:rotate(180deg);margin-left:auto}
.tk-disclosure-hd:focus-visible{outline:3px solid var(--c-500);outline-offset:-3px}
.tk-quiz-toolbar{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding-bottom:1rem;border-bottom:1px solid var(--bd);margin-bottom:1rem}
.tk-lesson .tk-split{align-items:stretch;gap:1.25rem}
.tk-workbench .tk-split>.lb-chart{padding:1rem;background:var(--bg-m);border:1px solid var(--bd);border-radius:var(--rs)}
.tk-workbench .tk-tbl-wrap{display:flex;flex-direction:column;border:1px solid var(--bd);border-radius:var(--rs);background:var(--bg-c)}
.tk-workbench .tk-tbl{margin:0}
.tk-workbench .tk-tbl-wrap:has(.tk-tbl-empty) .tk-tbl{flex:1}
.tk-workbench .tk-tbl th{white-space:normal;line-height:1.5}
.tk-workbench .tk-tbl-empty td{padding:2rem;line-height:1.8;white-space:normal;vertical-align:middle}
.tk-lesson .ev-key-h2{color:#1d4ed8}
.tk-lesson .ev-key-o2{color:#b91c1c}
[data-theme="dark"] .tk-lesson .ev-key-h2{color:#93c5fd}
[data-theme="dark"] .tk-lesson .ev-key-o2{color:#fca5a5}

/* The library exposes current scope and a direct return to a real recent lesson. */
.tk-hub .tk-catalog-intro{gap:.6rem 1rem}
.tk-hub .tk-resume-link{max-width:360px;font-size:.8rem;min-height:44px;padding:.5rem .8rem}
.tk-resume-link span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.tk-hub .tk-filter-summary:not(.tk-sr){display:flex;align-items:center;flex-wrap:wrap;gap:.4rem;margin:0 0 1rem;color:var(--t2);font-size:.84rem;line-height:1.8}
.tk-hub .tk-library-controls .tk-chip,.tk-hub .tk-sort-field .tk-select,.tk-hub .tk-library-controls .tk-recent a,.tk-hub .tk-library-controls .tk-clear{min-height:44px}
.tk-hub .tk-card-bd>.tk-filter-summary{padding:0 .1rem}
.tk-hub .tk-topic-sj{font-size:.76rem;line-height:1.65}
.tk-hub .tk-topic-bd>p{line-height:1.8}
.tk-library-source{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:.3rem 1rem;margin:-.3rem 0 1rem;font-size:.76rem;line-height:1.8;color:var(--t2)}
.tk-library-source span{display:inline-flex;align-items:center;gap:.4rem}
.tk-library-source i{color:var(--c-500)}
@media(max-width:1100px){
  .tk-workbench #lbCard{grid-template-columns:minmax(0,1fr) 290px}
  .tk-workbench .tk-model-panel>.tk-fsheet{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:1000px){
  .tk-workbench #lbCard{display:block}
  .tk-workbench #lbCard>.lb-dock{border-left:0;border-top:1px solid var(--bd)}
  .tk-workbench #lbCard .lb-toolbar{grid-template-columns:repeat(2,minmax(0,1fr));gap:.75rem 1rem}
  .tk-workbench .lb-toolbar>.tk-control-intro{grid-column:1/-1}
  .tk-workbench .lb-toolbar>.tk-btn-primary{grid-column:auto}
  .tk-workbench .lb-toolbar>:is(div,label,span){grid-column:auto}
  .tk-workbench .lb-toolbar>.tk-seg{grid-column:auto}
  .tk-workbench #lbCard:fullscreen,.tk-workbench #lbCard:-webkit-full-screen{display:block}
  .tk-workbench #lbCard:fullscreen>.lb-dock,.tk-workbench #lbCard:-webkit-full-screen>.lb-dock{max-height:none;overflow:visible}
}
@media(max-width:900px){
  .tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat:nth-child(3){border-left:0}
  .tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat:nth-child(n+3){border-top:1px solid var(--bd)}
}
@media(max-width:600px){
  .tk-content-date{margin-left:0;flex-basis:100%}
  .tk-lesson-context{gap:0 1rem;font-size:.73rem}
  .tk-lesson-context>a{min-height:44px}
  .tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat{padding:.85rem;column-gap:.55rem;min-height:120px}
  .tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat-ic{width:28px;height:28px;font-size:.8rem;border-radius:8px}
  .tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat-val{font-size:1.2rem}
  .tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat-lbl{font-size:.77rem}
  .tk-lesson .tk-stats:not(.pl-readouts):not(.rs-readouts) .tk-stat-sub{font-size:.74rem}
  .tk-workbench #lbCard .lb-toolbar{padding:1rem;gap:.75rem}
  .tk-workbench .lb-toolbar>:is(div,label,span){grid-column:1/-1}
  .tk-workbench .lb-toolbar>.tk-btn-primary{grid-column:1/-1}
  .tk-workbench .tk-model-panel>.tk-fsheet{grid-template-columns:minmax(0,1fr)}
  .tk-workbench .tk-model-panel .tk-frow{padding:1rem;border-right:0}
  .tk-guide{padding:.35rem 1rem}
  .tk-disclosure-hd{padding:.8rem 1rem}
  .tk-disclosure-hd h2{font-size:.94rem;gap:.55rem}
  .tk-disclosure-hint{font-size:.73rem}
  .tk-hub .tk-resume-link{max-width:100%;width:100%;justify-content:flex-start}
  .tk-hub .tk-library-controls .tk-clear{font-size:.78rem}
  .tk-library-source{font-size:.72rem}
}
@media(prefers-reduced-motion:reduce){.tk-disclosure-arrow,.tk-disclosure-hd{transition:none}}
@media print{
  .tk-lesson-context,.tk-control-intro,.tk-disclosure-hint,.tk-disclosure-arrow,.tk-quiz-toolbar button,.tk-library-source,.tk-resume-link{display:none!important}
  .tk-workbench #lbCard{display:block}
  .tk-workbench .tk-model-panel>.tk-fsheet{grid-template-columns:repeat(2,minmax(0,1fr))}
}