@font-face{font-family:'Atelier Math';src:url('fonts/atelier-math.ttf') format('truetype');font-display:swap}
.math-overlined-symbol{display:inline-block;font-style:italic;line-height:1.05;border-top:.065em solid currentColor;padding:.08em .04em 0}
math{font-family:'Atelier Math','STIX Two Math',math;font-size:1.08em;font-style:normal;line-height:normal}math[display=block]{margin:8px 0}math[display=inline]{vertical-align:middle}.lesson-math,.lesson-formula{overflow-x:auto;max-width:100%;padding:12px 18px;scrollbar-width:thin;font-size:calc(20px + var(--site-font-increase))}.lesson-math math,.lesson-formula math{min-width:max-content}.lesson-formula{background:#f0f3e9;border-radius:7px;margin-top:17px}.lesson-math{background:#f8f8f2;border-radius:6px;margin:12px 0}.lesson-kicker,.example-label{display:block;font:600 calc(10px + var(--site-font-increase))/1.6 var(--sans)!important;letter-spacing:1.7px;color:#6a7f59!important;margin:0 0 12px!important}
dialog.lesson-dialog{max-width:1000px;width:calc(100% - 40px)}.lesson-dialog .dialog-body{padding:35px 46px 45px}.lesson-dialog .dialog-body>h2{font-size:calc(38px + var(--site-font-increase));line-height:1.2}.lesson-sheet{color:#354c3f}.dialog-body .lesson-sheet p,.dialog-body .lesson-sheet li{font-size:calc(16px + var(--site-font-increase));line-height:1.85;margin-block:9px}.lesson-goal{padding:25px 28px;background:#eaf0e2;border-left:4px solid #799660;border-radius:0 9px 9px 0;margin-top:26px}.dialog-body .lesson-goal>p{font:calc(24px + var(--site-font-increase))/1.5 var(--serif);color:#294a38;margin:0 0 14px}.lesson-goal small{font-size:calc(12px + var(--site-font-increase));line-height:1.8;color:#6e7c65;display:block}.lesson-section{margin-top:38px}.lesson-section-heading{display:flex;gap:14px;align-items:center;margin-bottom:20px;border-bottom:1px solid #d7dfcc;padding-bottom:13px}.lesson-section-heading>span{font:italic calc(28px + var(--site-font-increase)) var(--serif);color:#8b9a72}.lesson-sheet .lesson-section-heading h3{margin:0;font-size:calc(29px + var(--site-font-increase))}.lesson-rules{display:grid;grid-template-columns:minmax(0,1fr);gap:18px}.lesson-sheet,.lesson-section,.lesson-rule,.worked-example,.lesson-practice,.worked-steps>li{min-width:0}.math-row{display:flex;flex-wrap:wrap;align-items:center;justify-content:center;gap:8px 22px}.math-row>math{flex:0 0 auto}.lesson-rule{border:1px solid #dfe4d5;border-radius:9px;padding:23px 25px;background:#fdfdf8}.lesson-sheet h4{font:calc(25px + var(--site-font-increase))/1.3 var(--serif);margin:0 0 10px;color:#294a38}.worked-example{background:#fffdf6;border:1px solid #e3ddc9;border-radius:10px;padding:27px;margin:20px 0}.worked-steps{list-style:none!important;counter-reset:worked;padding:0!important;margin:20px 0!important}.worked-steps>li{counter-increment:worked;position:relative;padding:0 0 18px 44px!important;margin:0 0 18px!important;border-bottom:1px solid #e0e5d8}.worked-steps>li:last-child{border-bottom:0;margin-bottom:0!important;padding-bottom:0!important}.worked-steps>li:before{content:counter(worked);position:absolute;left:0;top:2px;width:27px;height:27px;display:grid;place-items:center;border-radius:50%;background:#e5ecdb;color:#597048;font:600 calc(12px + var(--site-font-increase)) var(--sans)}.example-result,.solution-check{padding:17px 20px;background:#edf2e5;border-left:3px solid #8ba875;font-size:calc(15px + var(--site-font-increase));line-height:1.8}.lesson-pitfall{background:#f6eddb;border:1px solid #e7d8b8;padding:22px 26px;border-radius:9px;margin:28px 0}.lesson-pitfall>strong{color:#886c32;font-size:calc(14px + var(--site-font-increase))}.lesson-pitfall p{margin-bottom:0!important}.lesson-practice{padding:27px;border:1px solid #b7c8a5;border-radius:10px;margin-top:30px}.lesson-practice h3{font-size:calc(28px + var(--site-font-increase));margin-top:5px}.lesson-practice details{margin-top:23px;padding:20px;background:#edf2e5;border:0}.lesson-practice summary{font-size:calc(14px + var(--site-font-increase));font-weight:600;cursor:pointer}.lesson-practice details>p:first-of-type{margin-top:20px}.lesson-dialog .resource-dialog-tabs button{font-size:calc(13px + var(--site-font-increase));padding-bottom:13px}.lesson-dialog .extra-documents a{font-size:calc(13px + var(--site-font-increase))}
/* Give the challenge the full width of a reading desk. */
.puzzle-section{display:block}.puzzle-section>.section-heading{margin-bottom:35px}.puzzle-section .section-heading h2{max-width:740px}.puzzle-workspace{border:1px solid #dce1d1;border-radius:14px;overflow:hidden;background:#fcfcf7;box-shadow:0 12px 34px #344a2b08}.puzzle-workspace .puzzle-library{margin:0;display:flex;gap:10px;padding:23px 35px;background:#eaf0e2;border-bottom:1px solid #dce1d1}.puzzle-library label{font-size:calc(11px + var(--site-font-increase));font-weight:600;letter-spacing:1px}.puzzle-library select{font-size:calc(15px + var(--site-font-increase));padding:13px 15px;background:#fffef9;max-width:650px}.puzzle-focus{padding:35px 42px 40px}.puzzle-topline{font-size:calc(11px + var(--site-font-increase));letter-spacing:1px;display:flex;justify-content:space-between;margin-bottom:20px;gap:15px}.puzzle-focus>h3{font:calc(46px + var(--site-font-increase))/1.16 var(--serif);letter-spacing:-1px;margin:0 0 32px;color:var(--green)}.challenge-layout{display:grid;gap:30px;align-items:center}.challenge-layout.has-diagram{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}.challenge-statement{max-width:850px}.challenge-statement .lesson-kicker{margin-bottom:12px!important}.challenge-statement p,.challenge-statement li{font-size:calc(20px + var(--site-font-increase));line-height:1.85;color:#3e5544;margin:0 0 16px}.challenge-statement ol{padding-left:25px}.challenge-statement li{padding-left:5px;margin-bottom:10px}.puzzle-workspace .puzzle-diagram{margin:0;padding:22px 15px;background:#f4f5ed;border:1px solid #dfe6d3;border-radius:10px;min-width:0}.puzzle-workspace .puzzle-diagram>svg{max-width:600px;max-height:365px;display:block}.puzzle-workspace .puzzle-diagram>img{max-height:330px;width:100%;height:auto;display:block;mix-blend-mode:multiply}.puzzle-focus .puzzle-actions{margin-top:30px;display:flex;flex-wrap:wrap;gap:15px}.puzzle-focus .puzzle-actions .button{font-size:calc(13px + var(--site-font-increase));padding:15px 20px;gap:22px}.puzzle-focus .puzzle-answer{border-top:1px solid #d5dfc9;margin-top:30px;padding-top:30px;background:transparent;max-width:none;font-size:calc(17px + var(--site-font-increase))}.puzzle-worked-solution{max-width:900px;margin:0 auto}.puzzle-worked-solution>h3{font:calc(32px + var(--site-font-increase))/1.3 var(--serif);margin:0 0 25px;color:#294b37}.puzzle-worked-solution h4{font-size:calc(19px + var(--site-font-increase));margin:0 0 6px;font-weight:600}.puzzle-worked-solution p{font-size:calc(17px + var(--site-font-increase));line-height:1.85;margin:0}.puzzle-worked-solution .worked-steps>li{line-height:1.8;margin-bottom:22px!important;padding-bottom:22px!important}.puzzle-workspace .solution-diagram{max-width:680px;margin:25px auto 0}.puzzle-hint-box{background:#f3efdf;padding:25px;border-radius:8px}.puzzle-hint-box p{font-size:calc(18px + var(--site-font-increase));line-height:1.8;margin:0}.puzzle-bottom{display:flex;gap:20px;justify-content:space-between;align-items:center;padding:20px 35px;border-top:1px solid #dce1d1;background:#f4f6ee}.puzzle-bottom .next-puzzle{font-size:calc(13px + var(--site-font-increase));margin:0;padding:8px 0}.puzzle-bottom .puzzle-download{font-size:calc(11px + var(--site-font-increase));margin:0;line-height:1.7}.puzzle-bottom .puzzle-navigation{gap:25px}.solution-check{margin-top:20px}
/* Twelve experiments, one consistent control desk. */
.lab-activity-picker{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:10px;margin-bottom:26px}.lab-activity-picker [data-activity]{display:flex;align-items:center;gap:13px;padding:15px 17px;background:#f9faf3;border:1px solid #cdd8c0;border-radius:8px;color:#48613e;text-align:left;font-size:calc(13px + var(--site-font-increase));line-height:1.4;transition:background .2s,border-color .2s}.lab-activity-picker [data-activity]>span:first-child{font:italic calc(23px + var(--site-font-increase)) var(--serif);color:#8b9f70;min-width:27px;text-align:center}.lab-activity-picker [data-activity]:hover{background:#edf2e2;border-color:#91a877}.lab-activity-picker [data-activity][aria-pressed=true]{background:#36563e;color:#fffaf0;border-color:#36563e;box-shadow:0 5px 12px #2c4b3520}.lab-activity-picker [data-activity][aria-pressed=true]>span:first-child{color:#d5e3bc}#original-lab .lab-tabs{display:none}.lab-layout{grid-template-columns:minmax(255px,320px) minmax(0,1fr)}.extended-lab .lab-control h3{font-size:calc(33px + var(--site-font-increase));margin:17px 0 15px;line-height:1.15}.extended-lab .lab-control>p{font-size:calc(13px + var(--site-font-increase));line-height:1.85;max-width:none}.extended-lab .slider-label{font-size:calc(12px + var(--site-font-increase));margin-top:22px}.extended-lab input[type=range]{margin:10px 0 4px;width:100%;accent-color:#63834b}.extended-lab .slider-label span{font-size:calc(12px + var(--site-font-increase))}.lab-result{margin:23px 0 16px;padding:17px 10px;background:#e9efdf;border:1px solid #d5dfc7;border-radius:8px;font-size:calc(19px + var(--site-font-increase));overflow:auto}.lab-result math{margin:8px 0;min-width:max-content}.extended-lab .lab-insight{font-size:calc(13px + var(--site-font-increase));line-height:1.85;color:#59704b;margin:15px 0 20px}.extended-lab .canvas-caption{letter-spacing:.6px}.extended-lab .canvas-caption>span:last-child{font-size:calc(12px + var(--site-font-increase))}.extended-lab .canvas-footer{font-size:calc(11px + var(--site-font-increase));line-height:1.6}.extended-lab .lab-canvas{min-width:0}#extended-lab-plot{width:100%;height:auto;display:block;min-height:270px;flex:1;background:#fafbf5}.experiment-buttons{display:flex;flex-wrap:wrap;gap:8px;margin:22px 0}.experiment-buttons button{font-size:calc(12px + var(--site-font-increase));border:1px solid #98b37e;background:#f8faf3;border-radius:5px;padding:11px 13px}.experiment-buttons button:hover{background:#e1ebd4}.lab-data-label{font-size:calc(12px + var(--site-font-increase));line-height:1.6;display:block;margin:18px 0 8px}.lab-data-input{width:100%;font:calc(15px + var(--site-font-increase))/1.7 var(--sans);border:1px solid #acbd9a;border-radius:5px;padding:11px;background:#fffef8;color:#36563e;resize:vertical}.lab-data-help{font-size:calc(11px + var(--site-font-increase))!important;line-height:1.7!important}.lab-error{font-size:calc(13px + var(--site-font-increase));color:#9b4f33;line-height:1.7}.lab-section .section-heading>p{font-size:calc(13px + var(--site-font-increase))}
@media(max-width:1000px){.lab-activity-picker{grid-template-columns:repeat(3,minmax(0,1fr))}.lab-layout{gap:22px;padding:25px;grid-template-columns:minmax(225px,280px) minmax(0,1fr)}.challenge-layout.has-diagram{grid-template-columns:1fr}.puzzle-focus{padding:30px}.puzzle-workspace .puzzle-diagram{max-width:720px;width:100%;margin-inline:auto}.puzzle-focus>h3{font-size:calc(40px + var(--site-font-increase))}.lesson-dialog .dialog-body{padding:30px}}
@media(max-width:700px){.lab-layout{grid-template-columns:1fr}.lab-activity-picker{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.lab-activity-picker [data-activity]{padding:12px 11px;font-size:calc(12px + var(--site-font-increase));gap:9px}.lab-activity-picker [data-activity]>span:first-child{font-size:calc(20px + var(--site-font-increase));min-width:23px}.lab-layout .lab-control>p{font-size:calc(14px + var(--site-font-increase))}.lab-canvas{min-height:300px}.puzzle-focus{padding:25px 22px}.puzzle-focus>h3{font-size:calc(34px + var(--site-font-increase));margin-bottom:25px}.challenge-statement p,.challenge-statement li{font-size:calc(18px + var(--site-font-increase));line-height:1.8}.puzzle-workspace .puzzle-library{padding:20px 22px}.puzzle-library select{font-size:calc(13px + var(--site-font-increase))}.puzzle-bottom{flex-direction:column;align-items:flex-start;padding:18px 22px;gap:12px}.puzzle-focus .puzzle-actions{gap:12px}.puzzle-focus .puzzle-actions .button{font-size:calc(12px + var(--site-font-increase));padding:13px 15px;gap:15px}.puzzle-topline{font-size:calc(9px + var(--site-font-increase));line-height:1.7}.puzzle-worked-solution>h3{font-size:calc(28px + var(--site-font-increase))}.puzzle-worked-solution p{font-size:calc(16px + var(--site-font-increase))}.puzzle-worked-solution h4{font-size:calc(17px + var(--site-font-increase))}.puzzle-worked-solution .worked-steps>li{padding-left:37px!important}.puzzle-workspace .puzzle-diagram{padding:18px 8px}.lesson-math,.lesson-formula{font-size:calc(18px + var(--site-font-increase));padding:12px 8px}.lesson-dialog .dialog-body{padding:25px 21px}.lesson-dialog .dialog-body>h2{font-size:calc(30px + var(--site-font-increase))}.lesson-goal,.lesson-rule,.worked-example,.lesson-practice{padding:21px 18px}.lesson-dialog .dialog-body .lesson-goal>p{font-size:calc(21px + var(--site-font-increase))}.dialog-body .lesson-sheet p,.dialog-body .lesson-sheet li{font-size:calc(15px + var(--site-font-increase));line-height:1.85}.lesson-sheet .lesson-section-heading h3{font-size:calc(25px + var(--site-font-increase))}.lesson-sheet h4{font-size:calc(23px + var(--site-font-increase))}.worked-steps>li{padding-left:35px!important}.lesson-pitfall{padding:20px}.lesson-kicker,.example-label{font-size:calc(9px + var(--site-font-increase))!important}.lesson-dialog .resource-dialog-tabs button{font-size:calc(12px + var(--site-font-increase))}.lesson-practice details{padding:17px 12px}.lesson-practice h3{font-size:calc(25px + var(--site-font-increase))}.extended-lab .canvas-caption>span:last-child{font-size:calc(10px + var(--site-font-increase))}.extended-lab .canvas-footer{font-size:calc(10px + var(--site-font-increase))}.lab-result{font-size:calc(21px + var(--site-font-increase))}.puzzle-focus .puzzle-answer{padding-top:25px}}
@media print{.lesson-dialog .dialog-body{padding:10mm}.lesson-goal,.lesson-rule,.worked-example,.lesson-practice,.lesson-pitfall{break-inside:avoid}.lesson-section-heading{break-after:avoid}.lesson-sheet math{font-size:1em}.lesson-sheet p,.lesson-sheet li{font-size:calc(11pt + var(--site-font-increase))!important}.lesson-math,.lesson-formula{font-size:calc(13pt + var(--site-font-increase));overflow:visible}.lesson-sheet details{content-visibility:visible}.lesson-sheet details::details-content{content-visibility:visible;display:block}.lesson-sheet details>*:not(summary){display:block}.lesson-goal small{font-size:calc(10pt + var(--site-font-increase))}.lesson-section{margin-top:20px}.lesson-rule{padding:14px 18px}.worked-example{padding:18px}.lesson-dialog{width:100%!important}}
.practice-exercises{display:grid;gap:20px;margin-top:24px}.practice-exercise{padding:23px;background:#fffef8;border:1px solid #d9e1ce;border-radius:9px;min-width:0}.lesson-sheet .practice-exercise>h4{display:flex;gap:12px;align-items:center;font-size:calc(24px + var(--site-font-increase));margin-bottom:14px}.practice-exercise>h4>span{display:grid;place-items:center;flex:0 0 29px;height:29px;background:#e4ecd9;border-radius:50%;font:600 calc(13px + var(--site-font-increase)) var(--sans);color:#5b764b}.lesson-practice .practice-exercise details{margin-top:18px}.practice-question p{margin-top:0!important}.practice-exercise details .worked-steps{margin-top:23px!important}.extended-example{border-color:#b9cca4;background:#fbfdf5}.resource-level-label{font-size:calc(11px + var(--site-font-increase));padding:8px 12px}.resource-toolbar .search-box{margin-left:auto}
@media(max-width:600px){.practice-exercise{padding:19px 15px}.lesson-sheet .practice-exercise>h4{font-size:calc(21px + var(--site-font-increase));align-items:flex-start}.lesson-practice .practice-exercise details{padding:17px 11px}.resource-toolbar .search-box{margin-left:0}}
.lab-main-controls{margin-top:21px}.lab-field{margin-bottom:16px}.lab-choice-label{display:block;font-size:calc(12px + var(--site-font-increase));line-height:1.6;color:#557044;margin-bottom:7px}.lab-choice{width:100%;max-width:100%;border:1px solid #adbf98;background:#fffef8;color:#35573f;border-radius:5px;padding:10px 8px;font:calc(13px + var(--site-font-increase))/1.5 var(--sans)}.lab-display-options{border-block:1px solid #ccd9bd;padding:16px 0;margin:21px 0}.lab-display-options summary{font-size:calc(13px + var(--site-font-increase));font-weight:600;cursor:pointer;color:#4a6940}.lab-display-options[open] summary{margin-bottom:17px}.lab-check{display:flex;align-items:flex-start;gap:10px;font-size:calc(13px + var(--site-font-increase));line-height:1.7;cursor:pointer}.lab-check input{accent-color:#63834b;margin-top:4px;flex:none;width:16px;height:16px}.lab-display-options .lab-field{margin-bottom:13px}.lab-table-scroll{overflow:auto;margin:20px 0}.lab-table-scroll table{width:100%;border-collapse:collapse;font-size:calc(12px + var(--site-font-increase));line-height:1.7}.lab-table-scroll th,.lab-table-scroll td{text-align:left;padding:9px 8px;border-bottom:1px solid #d4dfc8}.lab-table-scroll th{background:#e8efdc;font-weight:600}.lab-investigation{display:grid;grid-template-columns:1fr 1fr;gap:35px;padding:31px 35px;margin-top:22px;background:#fcfdf7;border:1px solid #cbd9bf;border-radius:10px}.lab-investigation h3{font:calc(29px + var(--site-font-increase))/1.2 var(--serif);margin:0 0 20px;color:#36563f}.lab-investigation ol:not(.worked-steps){padding-left:20px;font-size:calc(14px + var(--site-font-increase));line-height:1.9}.lab-investigation li{margin-bottom:10px}.lab-presets{display:flex;flex-wrap:wrap;gap:10px;margin:0 0 23px}.lab-presets button{display:flex;gap:17px;align-items:center;padding:12px 15px;border:1px solid #b3c69d;background:#edf3e3;color:#46673b;border-radius:5px;font-size:calc(12px + var(--site-font-increase))}.lab-method{border-top:1px solid #d5e0ca;padding-top:20px}.lab-method summary{font-size:calc(13px + var(--site-font-increase));line-height:1.7;font-weight:600;cursor:pointer}.lab-method .worked-steps p{font-size:calc(14px + var(--site-font-increase));line-height:1.85}.lab-method .lesson-math{font-size:calc(18px + var(--site-font-increase))}.extended-lab{align-items:start}.extended-lab .lab-canvas{position:sticky;top:118px}.extended-lab .lab-control .slider-label{margin-top:10px}.extended-lab .lab-result{font-size:calc(18px + var(--site-font-increase))}.extended-lab .lab-control .lab-insight{font-size:calc(13px + var(--site-font-increase))}
@media(max-width:1000px){.lab-investigation{gap:25px;padding:28px}.lab-layout{grid-template-columns:280px minmax(0,1fr)}.extended-lab .lab-canvas{top:105px}.extended-lab .canvas-caption{flex-wrap:wrap}.extended-lab .canvas-caption>span:last-child{margin-left:0;font-size:calc(11px + var(--site-font-increase))}}
@media(max-width:700px){.lab-layout{grid-template-columns:1fr}.extended-lab .lab-canvas{position:static}.lab-investigation{grid-template-columns:1fr;padding:25px 20px;gap:25px}.lab-investigation h3{font-size:calc(27px + var(--site-font-increase))}.lab-investigation ol:not(.worked-steps){font-size:calc(14px + var(--site-font-increase))}.lab-main-controls{margin-top:25px}.lab-check{font-size:calc(13px + var(--site-font-increase))}.lab-choice{font-size:calc(13px + var(--site-font-increase))}.extended-lab .lab-result{font-size:calc(20px + var(--site-font-increase))}.lab-investigation-work{min-width:0}.lab-method .lesson-math{font-size:calc(17px + var(--site-font-increase))}}
.lab-investigation-intro,.lab-investigation-work,.extended-lab .lab-control{min-width:0}.lab-table-scroll caption{text-align:left;font-size:calc(10px + var(--site-font-increase));color:#79896b;line-height:1.7;padding-bottom:8px}
.lab-source-links{padding:14px 15px;background:#e8f0dd;border-left:3px solid #8daa70;border-radius:0 6px 6px 0;margin:19px 0}.lab-source-links>span{display:block;font-size:calc(10px + var(--site-font-increase));letter-spacing:.7px;color:#70865c;margin-bottom:9px}.lab-source-links button{display:flex;align-items:center;justify-content:space-between;gap:12px;width:100%;text-align:left;font-size:calc(12px + var(--site-font-increase));line-height:1.6;color:#46663b;padding:5px 0}.lab-source-links button:hover{color:#9c793d}.lab-source-links button+button{border-top:1px solid #d0ddc1;margin-top:4px;padding-top:9px}.lab-activity-picker [data-activity]>span:first-child{font-size:calc(20px + var(--site-font-increase))}.lab-activity-picker [data-activity]{min-height:65px}
@media(max-width:700px){.lab-activity-picker [data-activity]{min-height:60px}.lab-activity-picker [data-activity]>span:first-child{font-size:calc(17px + var(--site-font-increase));min-width:28px}.lab-source-links{padding:13px}.lab-source-links button{font-size:calc(12px + var(--site-font-increase))}}


/* Compact selectors keep the chosen experiment directly in view. */
.lab-activity-picker{display:block;position:sticky;top:var(--lab-header-height,96px);z-index:12;background:#edeee6;padding:12px 0;margin-bottom:16px;border-bottom:1px solid #d0d8c7}
.lab-selectors{display:grid;grid-template-columns:minmax(150px,.7fr) minmax(240px,1.8fr);gap:16px}
.lab-selectors>div{min-width:0}
.lab-selectors label{display:block;font-size:calc(10px + var(--site-font-increase));letter-spacing:.8px;font-weight:650;text-transform:uppercase;margin-bottom:5px;color:#657d57}
.lab-selectors select{display:block;width:100%;min-width:0;height:44px;border:1px solid #acbd99;border-radius:5px;background:#fffef8;color:#355640;padding:8px 34px 8px 12px;font:calc(13px + var(--site-font-increase)) var(--sans);cursor:pointer}
.lab-selectors select:focus-visible{outline:2px solid #b49554;outline-offset:3px}
.lab-chip{font-size:calc(9px + var(--site-font-increase));line-height:1.6}
.lab-notions{margin:22px 0;padding:28px;background:#f9faf3;border:1px solid #d5decb;border-radius:8px}
.lab-notions>h3{font-size:calc(28px + var(--site-font-increase));margin:10px 0 20px}
.lab-notions-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.lab-notions-grid article{padding:19px;background:#eef2e5;border-radius:6px;min-width:0}
.lab-notions-grid h4{font:600 calc(14px + var(--site-font-increase)) var(--sans);margin:0 0 9px}
.lab-notions-grid p{font-size:calc(13px + var(--site-font-increase));line-height:1.8;margin:0;color:#607454}
.lab-notions-grid math{font-size:calc(18px + var(--site-font-increase));overflow:auto;margin-top:14px}
.visually-hidden{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap}
@media(max-width:700px){
 .lab-activity-picker{top:var(--lab-header-height,74px);padding:9px 0;margin-bottom:12px}
 .lab-selectors{grid-template-columns:105px minmax(0,1fr);gap:9px}
 .lab-selectors label{font-size:calc(9px + var(--site-font-increase))}
 .lab-selectors select{font-size:calc(12px + var(--site-font-increase));padding-left:8px;padding-right:20px}
 .extended-lab .lab-canvas{grid-row:1;min-height:0}
 .extended-lab .lab-control{grid-row:2}
 #extended-lab-plot{min-height:220px}
 .lab-notions{padding:22px 18px}.lab-notions-grid{grid-template-columns:1fr}.lab-notions>h3{font-size:calc(25px + var(--site-font-increase))}
}

.extended-lab{align-items:start}
.extended-lab .lab-canvas{position:sticky;top:calc(var(--lab-header-height,96px) + var(--lab-picker-height,82px) + 12px)}
#extended-lab-plot{flex:none}
@media(max-width:700px){.extended-lab .lab-canvas{position:static}}

@media(max-width:700px){#extended-lab-plot .sphere-legend{display:none}}

.lab-proof{margin-top:20px;padding-top:20px;border-top:1px solid #cdd9bf}
.lab-proof-counter{font-size:calc(11px + var(--site-font-increase))!important;font-weight:650;color:#597648!important;margin:10px 0 15px!important}
.lab-proof-steps{list-style:none;padding:0;margin:0;counter-reset:proof}
.lab-proof-steps>li{counter-increment:proof;position:relative;padding:17px 14px 17px 40px;background:#edf2e5;border:1px solid #d3dfc6;border-radius:6px;margin-bottom:12px}
.lab-proof-steps>li:before{content:counter(proof);position:absolute;left:13px;top:18px;font-size:calc(11px + var(--site-font-increase));font-weight:700;color:#729052}
.lab-proof-steps h4{font:650 calc(13px + var(--site-font-increase))/1.5 var(--sans);margin:0 0 9px}
.lab-proof-steps p{font-size:calc(13px + var(--site-font-increase))!important;line-height:1.85!important;margin:0!important}
.lab-proof-steps .lesson-math{font-size:calc(18px + var(--site-font-increase));margin:13px 0 0;padding:12px 5px}
.lab-proof-actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:15px}
.lab-proof-actions button{font:600 calc(12px + var(--site-font-increase))/1.5 var(--sans);background:#36563e;color:#fffaf0;border-radius:5px;padding:11px 13px;min-height:43px}
.lab-proof-actions button+button{background:transparent;color:#5b7051;border:1px solid #b7c8a8}
.lab-proof-actions button:disabled{opacity:.5}
.lab-visual-options{padding:8px 0}
@media(max-width:700px){.lab-proof-steps h4{font-size:calc(15px + var(--site-font-increase))}.lab-proof-steps p{font-size:calc(14px + var(--site-font-increase))!important}.lab-proof-actions button{font-size:calc(13px + var(--site-font-increase))}}

/* Geometry drawings remain with their statement, before the solution. */
.lesson-geometry{margin:22px 0;padding:18px 18px 16px;border:1px solid #d6dfca;border-radius:10px;background:#fffef8;break-inside:avoid;min-width:0}.lesson-geometry-label{font:600 calc(11px + var(--site-font-increase))/1.6 var(--sans);letter-spacing:.6px;color:#557044;margin:0 0 6px}.lesson-geometry svg{display:block;width:100%;max-width:660px;max-height:390px;height:auto;margin:0 auto;overflow:visible}.lesson-geometry figcaption{font:calc(13px + var(--site-font-increase))/1.7 var(--sans);color:#65745e;border-top:1px solid #e3e9db;padding-top:12px;margin-top:6px}.worked-steps .lesson-geometry{margin:18px 0}.practice-question+.lesson-geometry{margin-top:18px}.lesson-geometry text{font-weight:500}.lesson-geometry-panels{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.lesson-geometry-panels svg{overflow:hidden;max-height:350px}.lesson-geometry-panels+figcaption{margin-top:12px}
@media(max-width:600px){.lesson-geometry{padding:12px 4px;margin:18px -5px}.lesson-geometry-label,.lesson-geometry figcaption{padding-left:8px;padding-right:8px}.lesson-geometry figcaption{font-size:calc(12px + var(--site-font-increase))}.lesson-geometry svg{max-height:320px}.lesson-geometry-panels{grid-template-columns:1fr;gap:14px}.lesson-geometry-panels svg{max-height:270px}.lesson-geometry-panels svg+svg{border-top:1px dashed #d6dfca;padding-top:12px}}
@media print{.lesson-geometry{box-shadow:none;border-color:#c3cdb9}.lesson-geometry svg{max-height:65mm;width:100%}.lesson-geometry figcaption{font-size:calc(9pt + var(--site-font-increase))}}
.lesson-programme{margin-top:30px;padding:20px 24px;background:#f0f3e9;border:1px solid #d6dfca;border-radius:9px;line-height:1.8}.lesson-programme summary{cursor:pointer;font-size:calc(14px + var(--site-font-increase));font-weight:600;color:#3c5d43}.lesson-programme a{text-decoration:underline;text-underline-offset:3px}.lesson-table-scroll{max-width:100%;overflow-x:auto;margin:18px 0}.lesson-table-scroll table{width:100%;border-collapse:collapse;font-size:calc(15px + var(--site-font-increase));text-align:center}.lesson-table-scroll caption{text-align:left;font-size:calc(13px + var(--site-font-increase));padding-bottom:9px;color:#65745e}.lesson-table-scroll th,.lesson-table-scroll td{padding:10px 14px;border:1px solid #cbd7bc}.lesson-table-scroll th{background:#eaf0e2;font-weight:600}.lesson-table-scroll td{background:#fffef8}@media(max-width:600px){.lesson-programme{padding:18px 15px}.lesson-table-scroll th,.lesson-table-scroll td{padding:9px 10px}.lesson-math>.math-row,.lesson-formula>.math-row{justify-content:flex-start}}