/* DT Classroom lab kit: shared look for the new interactive labs (cream paper, navy, yellow, hard shadows, as on the main site). */
:root{color-scheme:light;--paper:#f3efe6;--paper2:#fffdf7;--ink:#17212b;--navy:#16344c;--blue:#2463eb;--yellow:#f3c84b;--orange:#ef7a3a;--red:#d94d4d;--green:#2c9b6c;--line:#d8d0c2;--muted:#56636d;--shadow:#d7cebf;--tens:#2f7fe0;--comp:#d94d4d}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font:15px/1.55 Inter,system-ui,-apple-system,"Segoe UI",Arial,sans-serif}
button,input,select,textarea{font:inherit;color:inherit}button{cursor:pointer}
.lk-skip{position:absolute;left:-999px;top:0;background:#fff;color:#000;padding:8px 12px;z-index:99}.lk-skip:focus{left:8px;top:8px}
.lk-top{padding-right:210px!important;position:sticky;top:0;z-index:30;display:flex;align-items:center;gap:14px;padding:0 20px;height:62px;background:rgba(243,239,230,.96);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.lk-brand{display:flex;align-items:center;gap:10px;color:var(--navy);text-decoration:none}
.lk-logo{width:38px;height:38px;border-radius:8px;background:var(--navy);color:#fff;display:grid;place-items:center;font:800 12px "JetBrains Mono",ui-monospace,monospace;box-shadow:4px 4px 0 var(--yellow)}
.lk-brand b{font-size:16px;letter-spacing:-.03em;display:block;line-height:1.1}.lk-brand small{display:block;font-size:10px;color:#6d7780}
.lk-nav{margin-left:auto;display:flex;gap:8px;flex-wrap:wrap;align-items:center}
.lk-nav a,.lk-nav button{border:1px solid var(--line);background:#fff;border-radius:9px;padding:8px 12px;font-size:12px;font-weight:800;color:var(--navy);text-decoration:none}
.lk-nav a.on,.lk-nav a:hover,.lk-nav button:hover{border-color:var(--navy)}
.lk-wrap{width:min(1480px,calc(100% - 32px));margin:0 auto;padding:14px 0 40px}
.lk-kicker{display:inline-flex;align-items:center;gap:8px;font:700 10px "JetBrains Mono",ui-monospace,monospace;letter-spacing:.12em;text-transform:uppercase;color:#53616b}
.lk-kicker:before{content:"";width:28px;height:4px;background:var(--yellow)}
.lk-hero h1{margin:6px 0 6px;font-size:clamp(28px,3.6vw,42px);line-height:1;letter-spacing:-.04em;color:var(--navy);max-width:28ch}
.lk-hero p{margin:0;max-width:86ch;color:#53616b;font-size:14.5px;line-height:1.45}
.lk-tags{display:flex;gap:7px;flex-wrap:wrap;margin-top:9px}
.lk-tag{display:inline-flex;gap:6px;align-items:center;border:1px solid var(--line);background:#fff;border-radius:99px;padding:4px 11px;font:700 11px "JetBrains Mono",ui-monospace,monospace;color:var(--navy)}
.lk-tag.y{background:#fff6d6;border-color:#e6c75a}
.lk-grid{display:grid;grid-template-columns:330px minmax(0,1fr);gap:16px;align-items:start;margin-top:12px}
.lk-panel{background:var(--paper2);border:1px solid var(--line);border-radius:12px;padding:16px;box-shadow:5px 5px 0 var(--shadow);min-width:0}
.lk-panel+.lk-panel{margin-top:16px}.lk-lower .lk-panel+.lk-panel,.lk-main .lk-panel+.lk-panel{margin-top:0}
.lk-panel h2{margin:0 0 10px;font:700 11px "JetBrains Mono",ui-monospace,monospace;text-transform:uppercase;letter-spacing:.12em;color:var(--navy)}
.lk-panel h2:not(:first-child){margin-top:18px}
.lk-panel h3{margin:14px 0 6px;font-size:15px;color:var(--navy)}
.lk-f{display:grid;gap:3px;margin:10px 0;font-size:12.5px;font-weight:700;color:var(--navy)}
.lk-f>span{display:flex;justify-content:space-between;gap:8px;align-items:baseline}
.lk-f output{font:700 12px "JetBrains Mono",ui-monospace,monospace;color:var(--blue)}
.lk-f input[type=range]{width:100%;accent-color:var(--navy);margin:0;height:24px}
.lk-f select,.lk-f input[type=number],.lk-f input[type=text]{border:1px solid var(--line);border-radius:8px;padding:8px 10px;background:#fff;font-weight:600;width:100%}
.lk-check{display:flex;align-items:center;gap:8px;font-size:13px;font-weight:700;color:var(--navy);margin:8px 0}.lk-check input{width:18px;height:18px;accent-color:var(--navy)}
.lk-row{display:flex;gap:8px;flex-wrap:wrap;align-items:center}
.lk-btn{border:1px solid var(--line);background:#fff;border-radius:9px;padding:9px 13px;font-size:12.5px;font-weight:800;color:var(--navy);box-shadow:2px 2px 0 var(--shadow);text-decoration:none;display:inline-block}
.lk-btn:hover:not([disabled]){border-color:var(--navy);transform:translateY(-1px)}
.lk-btn.primary{background:var(--navy);border-color:var(--navy);color:#fff}
.lk-btn.yellow{background:var(--yellow);border-color:#c79e28;color:#272217}
.lk-btn[aria-pressed=true]{background:var(--yellow);border-color:#c79e28;color:#272217}
.lk-btn[disabled]{opacity:.5;cursor:default}
.lk-seg{display:inline-flex;border:1px solid var(--line);border-radius:10px;overflow:hidden;background:#fff;flex-wrap:wrap}
.lk-seg button{border:0;background:transparent;padding:8px 12px;font-size:12px;font-weight:800;color:var(--navy);border-right:1px solid var(--line)}
.lk-seg button:last-child{border-right:0}.lk-seg button[aria-pressed=true]{background:var(--navy);color:#fff}
:is(a,button,input,select,textarea,canvas,summary):focus-visible{outline:3px solid var(--blue);outline-offset:2px}
.lk-stage{background:#eaf2f4;background-image:linear-gradient(rgba(18,48,74,.07) 1px,transparent 1px),linear-gradient(90deg,rgba(18,48,74,.07) 1px,transparent 1px);background-size:20px 20px;border:2px solid var(--navy);border-radius:10px;overflow:hidden;position:relative;min-width:0}
.lk-stage svg,.lk-stage canvas{display:block;width:100%;height:auto}
.lk-stage .lk-label{position:absolute;left:12px;top:9px;font:700 10px "JetBrains Mono",ui-monospace,monospace;letter-spacing:.12em;color:#476071;pointer-events:none;text-transform:uppercase}
.lk-stats{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:9px;margin-top:12px}
.lk-stat{border:1px solid var(--line);border-radius:9px;padding:8px 11px;background:#fff}
.lk-stat small{display:block;font:700 9.5px "JetBrains Mono",ui-monospace,monospace;letter-spacing:.1em;text-transform:uppercase;color:#76818a}
.lk-stat b{display:block;font:800 18px "JetBrains Mono",ui-monospace,monospace;color:var(--navy);margin-top:2px}
.lk-stat.ok{border-color:#9fd2ae;background:#eef9f1}.lk-stat.warn{border-color:#e6b0a8;background:#fdf1ef}.lk-stat.warn b{color:var(--red)}.lk-stat.mid{border-color:#e6c75a;background:#fff8e0}
.lk-hint{font-size:12.5px;color:var(--muted);margin:8px 0 0}
.lk-note{border-left:4px solid var(--yellow);background:#fff6d6;padding:10px 13px;border-radius:0 9px 9px 0;font-size:13.5px;margin:12px 0}
.lk-live{min-height:1.4em;font-size:13px;font-weight:700;color:var(--navy)}
.lk-legend{display:flex;gap:12px;flex-wrap:wrap;font-size:12px;font-weight:700;margin-top:8px}.lk-legend i{display:inline-block;width:12px;height:12px;border-radius:3px;margin-right:5px;vertical-align:-1px}
.lk-tasks{list-style:none;margin:10px 0 0;padding:0;display:grid;gap:8px;counter-reset:t}
.lk-tasks li{counter-increment:t;display:grid;grid-template-columns:30px 1fr auto;gap:10px;align-items:start;border:1px solid var(--line);border-radius:10px;padding:10px 12px;background:#fff}
.lk-tasks li:before{content:counter(t);width:26px;height:26px;border-radius:50%;background:var(--navy);color:#fff;display:grid;place-items:center;font:800 12px "JetBrains Mono",monospace}
.lk-tasks li.done{border-color:#9fd2ae;background:#eef9f1}.lk-tasks li.done:before{content:"\2713";background:var(--green)}
.lk-tasks li.bad{border-color:#e6b0a8;background:#fdf1ef}
.lk-tasks .t-msg{display:block;font-size:12.5px;color:var(--muted);margin-top:2px}
.lk-tasks .t-state{font:800 11px "JetBrains Mono",monospace;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);align-self:center}
.lk-tasks li.done .t-state{color:var(--green)}.lk-tasks li.bad .t-state{color:var(--red)}
.lk-banner{display:none;margin-top:12px;border:2px solid var(--green);background:#eef9f1;border-radius:10px;padding:12px 14px;font-weight:800;color:#145c3a}
.lk-banner.show{display:block}
.lk-q textarea{width:100%;min-height:120px;border:1px solid var(--line);border-radius:9px;padding:10px 12px;background:#fff;resize:vertical;line-height:1.5}
.lk-model{margin-top:12px;border:1px solid var(--line);border-radius:10px;padding:12px 14px;background:#fff}
.lk-model[hidden]{display:none}
.lk-model ul{margin:6px 0;padding:0;list-style:none;display:grid;gap:6px}
.lk-model li label{display:flex;gap:9px;align-items:flex-start;font-size:13.5px}
.lk-model li input{margin-top:3px;width:17px;height:17px;accent-color:var(--navy)}
.lk-two{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:16px}
.lk-sheet{border:1px dashed #b9ae98;border-radius:10px;padding:14px 16px;background:#fff}
.lk-sheet h3{margin:0 0 6px}
.lk-sheet table{border-collapse:collapse;width:100%;font-size:13.5px}.lk-sheet td,.lk-sheet th{border:1px solid var(--line);padding:5px 9px;text-align:left;vertical-align:top}.lk-sheet th{background:#f6f2e8;width:38%}
.lk-sheet .ans{white-space:pre-wrap;min-height:2.5em}
.lk-related{display:flex;gap:9px;flex-wrap:wrap}
.lk-foot{width:min(1320px,calc(100% - 32px));margin:0 auto;padding:0 0 34px;color:var(--muted);font-size:12.5px}
.lk-foot a{color:var(--navy);font-weight:800}
.lk-source{font-size:12px;color:var(--muted);margin-top:10px}
.lk-bar{height:14px;border-radius:7px;background:#e6e0d5;overflow:hidden;display:flex}
@media(max-width:940px){.lk-grid{grid-template-columns:1fr}.lk-two{grid-template-columns:1fr}.lk-nav .lk-hide-s{display:none}.lk-tasks li{grid-template-columns:30px 1fr}.lk-tasks .t-state{grid-column:2}}
@media(prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important;scroll-behavior:auto!important}}
:root[data-reduced-motion="1"] *{transition:none!important;animation:none!important}

/* layout: fewer screens of scrolling. Wide: controls | model | challenge, all in view; the exam question and result sheet share a row. */
.lk-lower{display:grid;grid-template-columns:minmax(0,1fr);gap:16px;align-items:start;margin-top:14px}
.lk-stage svg{max-height:min(54vh,470px)}
.lk-chal>p{font-size:13px;line-height:1.4}
.lk-chal .lk-tasks{gap:6px}.lk-chal .lk-tasks li{font-size:13px;line-height:1.35;padding:7px 9px;grid-template-columns:26px 1fr;gap:8px}
.lk-chal .lk-tasks .t-state{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
.lk-chal .lk-tasks .t-msg{font-size:12px}
.lk-chal .lk-tasks select{max-width:100%}
@media(min-width:941px){
  .lk-main{grid-template-columns:290px minmax(0,1fr)}
  .lk-main .lk-chal{grid-column:1/-1}
  .lk-lower{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}
}
@media(min-width:1200px){
  .lk-main{grid-template-columns:290px minmax(0,1fr) 340px}
  .lk-main .lk-chal{grid-column:auto}
  .lk-main .lk-ctl,.lk-main .lk-chal{position:sticky;top:10px;max-height:calc(100vh - 20px);overflow:auto}
}
@media(max-width:940px){.lk-panel{padding:12px}.lk-tasks li{padding:8px 10px}.lk-stage svg{max-height:60vh}}
@media print{@page{margin:14mm}.lk-lower{display:block}body{background:#fff}.lk-top,.lk-hero,.lk-grid,.lk-foot,.lk-panel:not(.lk-printable),.lk-noprint,.dts-fab,#dts-open,.dta-fab{display:none!important}.lk-wrap{width:auto;padding:0}.lk-printable{display:block!important;box-shadow:none;border:0;padding:0}.lk-sheet{border:0;padding:0}.lk-sheet h2{display:block}}

/* compact layout: toolbar of controls + model on the left, collapsible challenge / exam / results on the right */
.lk-compact{padding-top:8px}
.lk-compact .lk-hero{display:flex;flex-wrap:wrap;align-items:center;gap:4px 18px}
.lk-compact .lk-hero .lk-kicker{flex-basis:100%}
.lk-compact .lk-hero h1{margin:0;font-size:clamp(24px,2.6vw,32px)}
.lk-compact .lk-hero .lk-tags{margin:0}
.lk-about{flex-basis:100%;order:5}.lk-about summary{cursor:pointer;font:700 12px "JetBrains Mono",monospace;color:#476071;list-style:none}.lk-about summary:before{content:"+ "}.lk-about[open] summary:before{content:"\2212 "}
.lk-about p{margin:6px 0 0;font-size:14px}
.lk-cmain{display:grid;grid-template-columns:minmax(0,1fr) 400px;gap:14px;align-items:start;margin-top:10px}
.lk-cl,.lk-cr{display:grid;gap:12px;min-width:0}
.lk-cl>.lk-panel,.lk-cr>.lk-panel{margin:0}
.lk-compact .lk-ctl h2{display:none}
.lk-compact .lk-ctl{padding:10px 14px}
.lk-compact #lkControls{display:flex;flex-wrap:wrap;gap:6px 16px;align-items:end}
.lk-compact #lkControls>.lk-f,.lk-compact #lkControls>.lk-seg{flex:1 1 150px;margin:0}.lk-compact #lkControls>.lk-row{flex:0 0 auto;margin:0}
.lk-compact .lk-stage svg{max-height:calc(100vh - 500px);min-height:200px}
.lk-compact [aria-label="Model"]{padding:12px}
.lk-compact .lk-stats{margin-top:8px}
.lk-acc{padding:0}
.lk-acc>summary{cursor:pointer;list-style:none;padding:12px 16px;font:700 11px "JetBrains Mono",ui-monospace,monospace;text-transform:uppercase;letter-spacing:.12em;color:var(--navy);display:flex;justify-content:space-between;align-items:center}
.lk-acc>summary::-webkit-details-marker{display:none}
.lk-acc>summary:after{content:"+";font-size:16px;font-weight:700}
.lk-acc[open]>summary:after{content:"\2212"}
.lk-acc[open]>summary{border-bottom:1px solid var(--line)}
.lk-ab{padding:10px 14px 14px}.lk-ab>p{font-size:13px;line-height:1.4}
.lk-compact .lk-live{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
@media(min-width:941px){.lk-cr{position:sticky;top:10px;max-height:calc(100vh - 20px);overflow:auto;align-content:start}}
@media(max-width:940px){.lk-cmain{grid-template-columns:1fr}.lk-compact .lk-stage svg{max-height:52vh}}
@media print{.lk-cmain{display:block}.lk-cl{display:none}.lk-acc:not(.lk-printable){display:none!important}.lk-acc>summary{display:none}.lk-ab{padding:0}}

.lk-who{display:grid;grid-template-columns:2fr 1fr 1.2fr;gap:8px;margin:10px 0 0;padding:8px 10px 10px;border:1px solid var(--lk-line,#d7dde6);border-radius:10px}
.lk-who legend{font-size:12px;font-weight:700;padding:0 6px;color:var(--lk-mut,#5b6675)}
.lk-who label{display:flex;flex-direction:column;gap:3px;font-size:12px;font-weight:600}
.lk-who input{font:inherit;font-size:14px;padding:6px 8px;border:1px solid var(--lk-line,#c4ccd8);border-radius:8px;background:var(--lk-bg,#fff);color:inherit;min-width:0}
@media(max-width:560px){.lk-who{grid-template-columns:1fr}}

.ms-3d{margin-top:8px;border:1px solid var(--lk-line,#d7dde6);border-radius:8px;overflow:hidden;background:linear-gradient(#f4efe6,#e8e2d6)}
.ms-hud{position:absolute;top:8px;right:10px;z-index:2;font:700 12px/1.2 system-ui;display:flex;gap:8px;align-items:center;background:rgba(255,255,255,.88);padding:4px 8px;border-radius:999px;color:#16344c}
.ms-hud i{display:block;width:80px;height:7px;border-radius:5px;background:#d4dbe2;overflow:hidden}.ms-hud b{display:block;height:100%;width:0;background:#e0a21a}
.ms-out{margin:8px 2px 0;font-size:14px;line-height:1.4;min-height:1.4em}

.ms-row{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:10px}.ms-row .lk-stage svg{max-height:210px;width:100%}
@media(max-width:700px){.ms-row{grid-template-columns:1fr}}

.tb-hud{position:absolute;top:8px;right:10px;z-index:2;font:700 12px/1.2 system-ui;background:rgba(255,255,255,.9);padding:4px 10px;border-radius:999px;color:#16344c}.tb-hud.bad{background:#fde6e8;color:#b02f3d}

/* Shared 3D pin labels (lab-3d.js ctx.label): tags that follow a point in the scene so students can see what is what */
.l3-pins{position:absolute;left:0;top:0;right:0;bottom:0;pointer-events:none;overflow:hidden;z-index:1}
.l3-pin{position:absolute;left:0;top:0;white-space:nowrap;font:700 12px/1.2 system-ui,sans-serif;color:#16344c;background:rgba(255,255,255,.94);border:1.5px solid #16344c;border-radius:6px;padding:3px 8px;box-shadow:0 1px 3px rgba(22,52,76,.25);will-change:transform}
.l3-pin::after{content:"";position:absolute;left:50%;bottom:-6px;margin-left:-5px;border:5px solid transparent;border-top-color:#16344c;border-bottom:0}
.l3-pin.good{border-color:#1a7f4b;color:#14502f}.l3-pin.good::after{border-top-color:#1a7f4b}
.l3-pin.warn{border-color:#b02f3d;color:#8a1f2b;background:#fde6e8}.l3-pin.warn::after{border-top-color:#b02f3d}
.l3-pinbtn{position:absolute;left:8px;bottom:8px;z-index:2;min-height:32px;padding:4px 10px;font:700 12px system-ui,sans-serif;color:#16344c;background:rgba(255,255,255,.94);border:1.5px solid #16344c;border-radius:999px;cursor:pointer}
.l3-pinbtn:focus-visible{outline:3px solid #ef7a3a;outline-offset:2px}
@media (max-width:560px){.l3-pin{font-size:11px;padding:2px 6px}}