:root{--ink:#14383b;--muted:#5e7273;--paper:#f6f7f2;--white:#fff;--green:#b7ef77;--teal:#087e83;--blue:#5876d7;--orange:#dc6d3a;--purple:#8d62be;--line:#dce4de;--shadow:0 10px 35px #173e3510;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none;scroll-behavior:auto}
*{box-sizing:border-box}body{margin:0}button,input,select,textarea{font:inherit}button,a,input,select,textarea{touch-action:manipulation}a{color:inherit}button{cursor:pointer}button:disabled{cursor:default;opacity:.5}button,a{ -webkit-tap-highlight-color:transparent}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #dd7c29;outline-offset:4px}button{border:0}h1,h2,h3,p{margin-top:0}h1{font-size:clamp(2.2rem,5vw,4.3rem);font-weight:650;letter-spacing:-.055em;line-height:1.08}h2{font-size:1.7rem;letter-spacing:-.035em}h3{font-size:1.12rem;letter-spacing:-.02em}p{line-height:1.65}small{font-size:.77rem}svg text{font-family:inherit}button,.btn{border-radius:10px}.topbar{max-width:1440px;margin:auto;padding:24px 5%;display:flex;align-items:center;justify-content:space-between;gap:24px}.brand{display:flex;align-items:center;gap:10px;text-decoration:none;font-weight:750;font-size:1.35rem;letter-spacing:-.04em}.brand-icon{width:43px;height:43px;background:var(--ink);color:var(--green);display:grid;place-items:center;border-radius:12px;font-family:Georgia,serif;font-style:italic;font-size:2rem;position:relative}.brand-icon span{position:absolute;right:5px;bottom:2px}.brand small{font-size:8px;letter-spacing:.14em;display:block;margin-top:3px;font-weight:600}.topbar nav{display:flex;gap:28px;font-size:.85rem}.topbar nav a{text-decoration:none;color:var(--muted);padding:8px 0}.topbar nav a:hover,.topbar nav a.active{color:var(--ink);box-shadow:0 2px var(--teal)}.school-tag{font-size:.65rem;letter-spacing:.08em;white-space:nowrap}.school-tag b{padding:7px 10px;background:#e6ede4;border-radius:7px;margin-left:5px}main{max-width:1320px;margin:auto;min-height:76vh;padding:14px 4% 60px}footer{padding:25px 5%;max-width:1440px;margin:auto;border-top:1px solid var(--line);font-size:.75rem;display:flex;justify-content:space-between;gap:20px;color:var(--muted)}footer a{text-decoration:none}.hero{background:var(--ink);border-radius:25px;min-height:375px;display:grid;grid-template-columns:1.05fr 1fr;overflow:hidden;position:relative;color:white}.hero-copy{padding:45px 45px;z-index:1}.eyebrow{text-transform:uppercase;font-size:.68rem;letter-spacing:.15em;font-weight:700;display:flex;align-items:center;gap:9px;margin-bottom:20px}.eyebrow:before{content:"";width:7px;height:7px;background:var(--green);border-radius:100%}.hero h1{margin-bottom:19px;font-size:clamp(2.4rem,4.3vw,4rem)}.hero h1 em{font-family:Georgia,serif;font-weight:400;color:var(--green)}.hero p{color:#c8d7d4;font-size:.91rem;max-width:410px;margin-bottom:25px}.hero-art{min-height:330px;position:relative;display:grid;align-items:center;padding:25px}.hero-art svg{width:100%;overflow:visible}.hero-art:before{content:"";position:absolute;width:360px;height:360px;border-radius:50%;background:#7cbd7520;filter:blur(50px)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:13px;padding:12px 18px;text-decoration:none;font-weight:650;font-size:.85rem;line-height:1.4;background:var(--ink);color:white;border:1px solid transparent}.btn:hover{filter:brightness(1.12)}.btn.lime{background:var(--green);color:var(--ink)}.btn.light{background:white;border-color:var(--line);color:var(--ink)}.btn.ghost{background:transparent;color:var(--ink);border-color:var(--line)}.hero .btn.ghost{color:white;border-color:#496566;margin-left:8px}.intro-strip{display:flex;gap:28px;padding:20px 4px;font-size:.77rem;color:var(--muted);border-bottom:1px solid var(--line);margin-bottom:35px}.intro-strip b{color:var(--ink)}.section-head{display:flex;justify-content:space-between;align-items:end;gap:25px;margin-bottom:18px}.section-head h2{margin-bottom:6px}.section-head p{font-size:.85rem;color:var(--muted);margin:0}.search{display:flex;align-items:center;border:1px solid var(--line);border-radius:11px;background:white;padding:0 13px;gap:10px;min-width:245px}.search input{border:0;background:transparent;padding:12px 0;min-width:0;width:100%;outline:none;color:var(--ink)}.filters{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-bottom:22px}.chip{font-size:.78rem;border:1px solid var(--line);color:var(--muted);padding:9px 16px;background:transparent;border-radius:30px}.chip.active{background:var(--ink);color:white;border-color:var(--ink)}.filter-divider{height:24px;border-left:1px solid var(--line);margin:0 5px}.count{font-size:.72rem;color:var(--muted);margin-left:auto}.card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.lab-card{border:1px solid var(--line);border-radius:17px;background:white;text-decoration:none;overflow:hidden;transition:transform .18s,box-shadow .18s;display:flex;flex-direction:column;min-width:0}.lab-card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}.card-art{height:128px;background:var(--tint,#ebf2eb);position:relative;padding:5px 20px}.card-art svg{height:100%;width:100%}.card-content{padding:20px;display:flex;flex-direction:column;flex:1}.card-meta{font-size:.64rem;letter-spacing:.05em;color:var(--muted);display:flex;gap:8px;align-items:center;margin-bottom:12px}.badge{display:inline-block;font-size:.66rem;border-radius:5px;padding:4px 7px;background:#edf3eb;color:#355c42;white-space:nowrap}.badge.optional{background:#f5eddd;color:#79571e}.lab-card h3{margin-bottom:8px;font-size:1.13rem}.lab-card p{color:var(--muted);font-size:.81rem;margin-bottom:18px}.card-bottom{font-size:.7rem;display:flex;align-items:center;justify-content:space-between;margin-top:auto}.card-bottom .arrow{font-size:1.3rem;color:var(--teal)}.state{font-size:.66rem;color:var(--teal)}.roadmap-banner{padding:24px;background:#eaf0e4;border-radius:15px;display:flex;justify-content:space-between;align-items:center;margin-top:32px;gap:20px}.roadmap-banner p{margin:6px 0 0;font-size:.8rem;color:var(--muted)}.roadmap-banner h3{margin:0}.breadcrumbs{display:flex;align-items:center;gap:10px;font-size:.75rem;color:var(--muted);margin:8px 0 23px}.breadcrumbs a{text-decoration:none}.lab-heading{display:flex;justify-content:space-between;align-items:center;gap:20px}.lab-heading h1{font-size:clamp(1.9rem,3.5vw,2.8rem);margin:10px 0 12px}.lab-heading p{max-width:780px;font-size:.91rem;color:var(--muted);margin-bottom:14px}.lab-heading .badge{margin-right:6px}.lab-tools{display:flex;gap:8px;flex-shrink:0}.icon-btn{border:1px solid var(--line);background:white;padding:10px 13px;color:var(--ink);font-size:.82rem}.learning-goal{font-size:.8rem;background:#eaf1e6;border-left:3px solid #75ac53;padding:11px 15px;border-radius:0 8px 8px 0;margin-bottom:20px;line-height:1.6}.prereq{font-size:.75rem;color:var(--muted);margin-bottom:20px}.prereq a{color:var(--teal)}.tabs{display:flex;gap:6px;border-bottom:1px solid var(--line);margin-bottom:24px}.tab{padding:13px 20px;color:var(--muted);background:transparent;border-radius:0;font-size:.83rem;border-bottom:3px solid transparent}.tab.active{color:var(--ink);border-bottom-color:var(--teal);font-weight:700}.tab small{margin-right:6px;color:var(--teal)}.lab-layout{display:grid;grid-template-columns:minmax(0,1fr) 310px;gap:20px;align-items:start}.experiment{background:white;border:1px solid var(--line);border-radius:17px;overflow:hidden;min-width:0}.experiment-top{padding:17px 21px;display:flex;align-items:center;justify-content:space-between;gap:12px;border-bottom:1px solid var(--line)}.experiment-top h3{margin:0;font-size:.85rem}.experiment-top span{font-size:.65rem;color:var(--muted)}.plot-wrap{padding:12px 12px 0;position:relative;overflow:hidden}.plot-wrap svg{width:100%;display:block;aspect-ratio:650 / 370;height:auto}.plot-description{font-size:.75rem;line-height:1.55;color:var(--muted);margin:0;padding:5px 20px 12px}.readouts{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;background:var(--line);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}.readout{background:#f8faf6;padding:13px 15px;min-width:0}.readout small{display:block;color:var(--muted);font-size:.65rem;margin-bottom:4px}.readout strong{font-size:1.05rem;font-weight:650;overflow-wrap:anywhere}.controls{padding:18px 21px;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:19px 24px}.control label{display:flex;justify-content:space-between;gap:10px;font-size:.77rem;margin-bottom:8px}.control output{font-variant-numeric:tabular-nums;color:var(--teal);font-weight:700}.control input[type=range]{width:100%;accent-color:var(--teal);margin:0;min-height:25px}.control select{width:100%;padding:9px;border:1px solid var(--line);border-radius:8px;background:white;font-size:.78rem;color:var(--ink)}.control button{width:100%;padding:10px;color:var(--ink);background:#eaf1e6}.lab-actions{display:flex;align-items:center;gap:8px;padding:0 20px 18px}.lab-actions button{font-size:.75rem}.formula{font-family:Cambria,"Cambria Math",Georgia,serif;font-size:1.18rem;line-height:1.8;background:#f2f5ee;border-radius:10px;padding:16px 20px;margin:15px 0;overflow-wrap:anywhere}.formula sup,.formula sub{font-size:.73em}.guide{background:#f0f3e9;border:1px solid #dce5d4;border-radius:17px;padding:22px}.guide .eyebrow{font-size:.6rem;color:#66815c;margin-bottom:13px}.guide .eyebrow:before{background:#6d9d4e}.guide h3{font-size:1.08rem;line-height:1.4}.guide p,.guide li{font-size:.81rem;line-height:1.7}.step-number{border-radius:50%;width:23px;height:23px;background:#dcebcf;display:inline-grid;place-items:center;font-size:.7rem;flex-shrink:0}.guide-step{display:flex;gap:10px;margin:15px 0}.guide-step p{margin:0}.guide details{border-top:1px solid #d8e1ce;margin-top:18px;padding-top:15px;font-size:.78rem}.guide summary{cursor:pointer;font-weight:650;line-height:1.5}.guide details p{margin:12px 0 0}.observation{margin:20px 0 0;padding:18px 22px;border:1px solid var(--line);border-radius:12px;background:white;font-size:.85rem;line-height:1.7}.observation b{color:var(--teal)}.explanation{max-width:850px}.explanation section{background:white;border:1px solid var(--line);border-radius:14px;padding:24px;margin-bottom:16px}.explanation p,.explanation li{font-size:.9rem;line-height:1.8}.explanation .trap{background:#fbf2e5;border-color:#efdfc8}.worked{border-left:3px solid var(--teal);padding-left:18px;font-size:.85rem;line-height:1.9}.practice-grid{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:22px}.exercise{padding:25px;background:white;border:1px solid var(--line);border-radius:15px;margin-bottom:16px}.exercise .q-num{font-size:.66rem;color:var(--teal);font-weight:750;text-transform:uppercase;letter-spacing:.1em;margin-bottom:12px}.exercise h3{font-size:1.06rem;line-height:1.65}.options{display:grid;gap:9px;margin:18px 0}.option{padding:13px 15px;background:#f5f7f2;border:1px solid var(--line);text-align:left;font-size:.85rem;color:var(--ink)}.option.selected{border-color:var(--teal);background:#e4f4f1}.option.correct{border-color:#478841;background:#eaf4df}.option.incorrect{border-color:#bf6946;background:#fff0e7}.numeric-answer{display:flex;gap:10px;align-items:center;margin:17px 0}.numeric-answer input{max-width:240px;width:100%;border:1px solid #bbcbbf;border-radius:9px;padding:12px;color:var(--ink)}.feedback{padding:15px;border-radius:9px;background:#eef4e8;font-size:.83rem;line-height:1.7;margin-top:15px}.feedback.wrong{background:#fff1e4}.exercise details{margin-top:15px;font-size:.8rem;line-height:1.8}.exercise summary{cursor:pointer;color:var(--teal);font-weight:650}.practice-note{padding:20px;background:#eaf0e4;border-radius:15px;font-size:.82rem;line-height:1.7}.exercise textarea{width:100%;height:105px;border:1px solid var(--line);border-radius:9px;padding:12px;font-size:.85rem;resize:vertical}.success-line{font-size:.78rem;color:#347144}.empty{padding:60px 10px;text-align:center;grid-column:1/-1}.page-title{max-width:800px;margin:20px 0 30px}.page-title h1{font-size:2.8rem}.page-title p{color:var(--muted)}.coverage{border:1px solid var(--line);border-radius:12px;overflow:auto;background:white;margin:25px 0}.coverage table{border-collapse:collapse;width:100%;font-size:.8rem}.coverage th,.coverage td{padding:15px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top;line-height:1.7}.coverage th{background:#edf2e8;white-space:nowrap}.coverage td a{display:inline-block;color:var(--teal);margin-right:10px}.info-panel{background:white;border:1px solid var(--line);border-radius:14px;padding:25px;margin-bottom:18px;line-height:1.8;font-size:.88rem}.info-panel h2{font-size:1.3rem}.info-panel ul{padding-left:20px}.info-panel a{color:var(--teal)}.progress-summary{display:grid;grid-template-columns:repeat(3,1fr);gap:15px;margin-bottom:20px}.progress-summary>div{border:1px solid var(--line);border-radius:13px;background:white;padding:22px}.progress-summary strong{display:block;font-size:2rem;margin-bottom:5px}.progress-summary span{font-size:.78rem;color:var(--muted)}.progress-list{list-style:none;padding:0}.progress-list li{background:white;border:1px solid var(--line);border-radius:10px;margin-bottom:9px;display:flex;gap:15px;align-items:center;padding:14px 17px}.progress-list a{flex:1;text-decoration:none;font-size:.85rem}.progress-list small{color:var(--muted)}.progress-track{height:5px;background:#e0e8d9;border-radius:3px;margin:15px 0;overflow:hidden}.progress-track i{display:block;height:100%;background:var(--teal)}.toggle-line{display:flex;gap:11px;align-items:start}.toggle-line input{accent-color:var(--teal);margin-top:7px;width:18px;height:18px}.toast{position:fixed;bottom:20px;left:50%;transform:translateX(-50%);background:var(--ink);color:white;padding:14px 23px;border-radius:12px;font-size:.83rem;box-shadow:var(--shadow);z-index:50;max-width:90vw}.skip{position:absolute;top:-80px;left:12px;z-index:100;background:white;padding:15px}.skip:focus{top:12px}.mobile-stage{display:none}.data-table{overflow-x:auto;padding:0 20px 15px}.data-table table{border-collapse:collapse;font-size:.75rem;width:100%;text-align:center}.data-table td,.data-table th{border:1px solid var(--line);padding:8px}.data-table th{background:#f1f5ed}.gallery-title{font-size:.7rem;color:var(--muted);margin:0 0 12px}.secondary-text{color:var(--muted);font-size:.8rem}.done-button{margin-top:22px}.wide-mode .lab-layout{grid-template-columns:1fr}.wide-mode .guide{max-width:none}.wide-mode .plot-wrap svg{max-height:65vh}.print-only{display:none}
@media(min-width:1300px){.hero-art{padding-right:40px}.hero-copy{padding:50px}.hero{min-height:395px}}
@media(max-width:1000px){.topbar nav{gap:17px}.lab-layout{grid-template-columns:minmax(0,1fr) 265px}.card-grid{grid-template-columns:repeat(2,1fr)}.hero-copy{padding:35px}.practice-grid{grid-template-columns:1fr}.practice-note{order:-1}.hero-art{padding:5px}.lab-heading{align-items:start}.lab-tools{flex-direction:column}}
@media(max-width:760px){.topbar{padding:17px 5%;flex-wrap:wrap;gap:13px}.topbar nav{order:3;width:100%;justify-content:space-between;font-size:.76rem;gap:10px}.brand{font-size:1.17rem}.brand small{font-size:7px}.brand-icon{width:37px;height:37px}.hero{grid-template-columns:1fr}.hero-copy{padding:30px 25px 15px}.hero h1{font-size:2.8rem}.hero-art{height:200px;min-height:0;max-width:420px;width:100%;margin:0 auto;padding:0 25px}.hero p{font-size:.85rem}.hero .btn{font-size:.78rem;padding:11px 13px}.intro-strip{gap:15px;font-size:.68rem;flex-wrap:wrap;margin-bottom:26px}.section-head{align-items:stretch;flex-direction:column;gap:15px}.search{min-width:0}.lab-layout{grid-template-columns:1fr}.guide{order:-1;padding:18px}.guide-step{margin:10px 0}.guide h3{margin-bottom:10px}.card-grid{gap:12px}.card-art{height:100px;padding:3px 8px}.card-content{padding:15px}.lab-card h3{font-size:.96rem}.lab-card p{font-size:.75rem}.card-meta{font-size:.57rem;flex-wrap:wrap}.card-bottom{font-size:.65rem}.filters{gap:6px}.chip{padding:8px 12px;font-size:.72rem}.count{width:100%;margin-top:6px}.lab-heading h1{font-size:2rem}.lab-heading p{font-size:.84rem}.lab-tools .icon-btn{font-size:.65rem;padding:8px}.tabs{gap:0}.tab{padding:12px 13px;font-size:.78rem;flex:1}.readout{padding:11px}.readout strong{font-size:.92rem}.readout small{font-size:.6rem}.controls{padding:17px;gap:16px}.plot-wrap{padding:4px 0 0}.plot-wrap svg{aspect-ratio:650 / 405}.roadmap-banner{align-items:start;flex-direction:column}.progress-summary{gap:9px}.progress-summary>div{padding:15px}.progress-summary strong{font-size:1.5rem}.progress-summary span{font-size:.7rem}.page-title h1{font-size:2.15rem}footer{flex-wrap:wrap;font-size:.66rem;gap:10px}.explanation section,.exercise{padding:20px}.breadcrumbs{flex-wrap:wrap}.progress-list li{flex-wrap:wrap}.progress-list a{min-width:65%}}
@media(max-width:390px){.card-grid{grid-template-columns:1fr}.card-art{height:115px}.lab-heading{display:block}.lab-tools{flex-direction:row;margin-bottom:15px}.hero h1{font-size:2.5rem}.hero .btn.ghost{margin-left:0;margin-top:8px}.readouts{grid-template-columns:1fr}.readout{display:flex;justify-content:space-between;gap:15px}.controls{grid-template-columns:1fr}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}
@media print{.topbar nav,.lab-tools,.tabs,.controls,.lab-actions,.guide,.done-button,footer,.btn,.search,.filters{display:none!important}body{background:white}.lab-layout{display:block}main{max-width:none;padding:0}.experiment,.explanation section{break-inside:avoid;box-shadow:none}.plot-wrap svg{max-height:340px}.print-only{display:block}a{text-decoration:none}.hero{color:black;background:white}.hero-art{display:none}}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.hero-caption{color:#b7d0ba;font-size:.72rem;position:absolute;bottom:37px;left:40%;letter-spacing:.04em}.hero-art svg text{fill:#bbd1bf}.plot-wrap svg{max-height:600px}.exercise details p{margin:8px 0}.explanation .eyebrow{margin-bottom:15px}.explanation h2{font-size:1.4rem;line-height:1.5}

.guide-fold>summary{display:none}.guide-fold{border:0!important;margin:0!important;padding:0!important}@media(max-width:760px){.guide-fold>summary{display:list-item;padding:4px 0;font-size:.78rem}.guide h3{font-size:.95rem}.guide .eyebrow{margin-bottom:9px}.hero-caption{bottom:10px;left:30%;font-size:.6rem}.plot-wrap svg.function-plot text{font-size:20px}.controls{gap:14px}.lab-actions{flex-wrap:wrap}}

math{font-family:"STIX Two Math","Cambria Math",math,serif;color:inherit;font-size:1.07em}math.math-display{display:block math;font-size:1.18rem;max-width:100%;overflow-x:auto;overflow-y:hidden;padding:12px 0;margin:3px 0}math.math-inline{white-space:nowrap;vertical-align:-.08em}.math-text{line-height:inherit}.formula{font-family:inherit;overflow-x:auto;overscroll-behavior-x:contain}.formula .math-text{display:block;min-width:0}.formula math{margin:0}.explanation p,.worked,.exercise h3,.exercise details p{line-height:1.95}.lab-heading p math{font-size:1em}.readout math{font-size:1em}@media(max-width:760px){math.math-display{font-size:1.06rem}.formula{padding:10px 12px}.exercise h3{line-height:1.9}}

.drag-hint{font-size:.73rem;line-height:1.65;margin:0;padding:9px 20px;background:#f1f6ed;color:#41674d;border-top:1px solid var(--line)}#visual:has(.drag-hint) svg{cursor:ew-resize;touch-action:pan-y}#visual.dragging svg{cursor:grabbing;touch-action:none}.discovery-card{margin-top:20px;border-top:1px solid #d8e1ce;padding-top:20px}.discovery-card h4{font-size:.86rem;margin:0 0 10px}.discovery-card label{font-size:.73rem;font-weight:650;display:block;margin-bottom:7px}.discovery-card textarea{width:100%;height:77px;border:1px solid #c2d2b8;border-radius:8px;padding:9px;font-size:.78rem;resize:vertical;line-height:1.5;background:#fffefb;color:var(--ink)}.discovery-card .btn{font-size:.74rem;margin-top:9px;width:100%;padding:10px}.discovery-card .discovery-action{margin:13px 0 0;font-size:.78rem}.discovery-card details{background:#e7efdd;padding:12px!important;border-radius:9px;margin-top:12px}.control[hidden]{display:none!important}@media(max-width:760px){.discovery-card{margin-top:14px;padding-top:14px}.discovery-card h4{font-size:.83rem}.drag-hint{font-size:.7rem;padding:9px 15px}}

.guide-fold>summary{display:list-item!important;font-size:.78rem;padding:5px 0}.discovery-card>summary{font-size:.8rem;color:#315e40;margin-bottom:12px}.discovery-card>h4{display:none}.discovery-card[open]>summary{margin-bottom:15px}.guide>.discovery-card{border:1px solid #d1dfc4;border-radius:10px;padding:14px!important;background:#e7efdd}.guide>.discovery-card:not([open])>summary{margin:0}.guide .guide-fold:not([open]){margin-bottom:5px!important}

@media(min-width:761px) and (max-width:1000px){.lab-layout{grid-template-columns:1fr}.guide{order:-1}.guide>h3{font-size:1rem}.guide>.discovery-card{margin-top:10px}.guide{padding:17px}}

.math-run{display:inline-block;max-width:100%;overflow-x:auto;overflow-y:hidden;vertical-align:middle;line-height:1.55;padding:2px 1px;overscroll-behavior-x:contain}.math-run math{white-space:nowrap}.math-run::-webkit-scrollbar{height:3px}.math-run::-webkit-scrollbar-thumb{background:#afc4a5;border-radius:2px}

.numeric-answer{min-width:0;max-width:100%}.numeric-answer input{min-width:0;flex:1 1 0}.numeric-answer button{flex:0 0 auto}

.practice-grid>*{min-width:0}@media(max-width:1000px){.practice-grid{grid-template-columns:minmax(0,1fr)}}

.hands-on{background:#eff4e8!important}.hands-on li{padding-left:4px;margin-bottom:10px}.hands-on ol{padding-left:22px}.hands-on summary{cursor:pointer;color:var(--teal);font-weight:650;font-size:.82rem}.hands-on .badge{font-family:inherit;font-weight:500;vertical-align:middle}
/* Lehrvio learning workspace */
.topbar{max-width:none;background:#103c40;color:#fff;padding:18px max(4%,calc((100vw - 1320px)/2));box-shadow:0 4px 16px #12383c14}.topbar nav a{color:#d2e5e2}.topbar nav a.active,.topbar nav a:hover{color:white;box-shadow:0 2px #b7ef77}.topbar .brand-icon{background:#fff;color:#103c40}.school-tag b{color:#123c40}.hero{margin-top:20px}.start-grid{display:grid;grid-template-columns:minmax(0,1.3fr) minmax(0,1fr);gap:22px}.start-card,.plain-bridge,.extension{background:#fff;border:1px solid var(--line);border-radius:18px;padding:28px;min-width:0}.start-card .eyebrow{color:var(--teal)}.lead{font-size:1.05rem;line-height:1.8}.learning-route{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:24px 0}.learning-route div{padding:15px;border-radius:12px;background:#edf5f3}.learning-route b,.learning-route span{display:block}.learning-route b{font-size:.83rem;margin-bottom:8px}.learning-route span{font-size:.78rem;color:var(--muted);line-height:1.5}.recovery{border-top:1px solid var(--line);padding-top:15px;margin-top:20px;font-size:.8rem}.recovery a{display:block;margin:9px 0;color:var(--teal)}.tabs{scroll-margin-top:15px}.vocabulary{display:grid;grid-template-columns:1fr 1fr;gap:14px}.vocabulary div{background:#edf4f3;border-radius:10px;padding:16px;min-width:0}.vocabulary dt{font-weight:700;margin-bottom:6px}.vocabulary dd{margin:0;font-size:.87rem;line-height:1.6}.explanation .plain-bridge{border-left:4px solid var(--teal)}.mini-workshop{border-top:1px solid var(--line);margin-top:22px;padding-top:20px}.reflection{border-top:1px solid var(--line);margin-top:24px;padding-top:20px;font-size:.85rem}.criterion{display:flex;align-items:flex-start;gap:11px;padding:10px 0;line-height:1.55}.criterion input{width:20px;height:20px;flex:0 0 20px;accent-color:var(--teal);margin-top:2px}.transfer-exercise{border-top:4px solid var(--teal)}.practice-note .btn{display:flex;margin:12px 0}.task-status,.result-label{font-size:.8rem;color:#426863}.task-status{margin:14px 0}.result-label{margin:12px 0 0!important}.coverage td,.coverage th{vertical-align:top;line-height:1.6}.coverage td a{display:inline-block;margin:5px 2px}.feedback{overflow-wrap:anywhere}.option{min-height:46px}.tab{min-height:48px}.btn,.icon-btn{min-height:44px}summary{min-height:44px;align-content:center}.extension .math-display{max-width:100%}.start-card h2{font-size:1.6rem}.card-art{height:105px}.tab small{font-variant-numeric:tabular-nums}.practice-note .eyebrow{color:var(--teal)}
@media(max-width:900px){.start-grid{grid-template-columns:1fr}.learning-route{grid-template-columns:repeat(3,1fr)}.topbar{padding:16px 4%}.school-tag{display:none}}
@media(max-width:600px){.topbar{gap:16px}.topbar nav{gap:15px;justify-content:space-between;width:100%}.topbar .brand small{font-size:7px}.start-card,.plain-bridge,.extension{padding:20px}.learning-route{grid-template-columns:1fr}.learning-route div{display:flex;gap:12px;align-items:center}.learning-route b{margin:0;min-width:92px}.vocabulary{grid-template-columns:1fr}.tabs{gap:0}.tab{padding:12px 8px;font-size:.76rem;flex:1}.tab small{display:block;margin:0 0 4px}.start-card .lead{font-size:.96rem}.coverage{max-width:100%;overflow-x:auto}.coverage table{min-width:600px}.criterion{font-size:.85rem}.card-art{height:100px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{transition:none!important;animation:none!important;scroll-behavior:auto!important}}
@media print{.start-grid,.vocabulary,.learning-route{display:block}.start-card,.plain-bridge,.extension,.mini-workshop{break-inside:avoid}.topbar,.tabs,.done-button,.lab-tools,.lab-actions,.practice-note,.numeric-answer,.options,button{display:none!important}.start-card,.plain-bridge,.extension{border:1px solid #aaa;margin-bottom:12px}.coverage table{min-width:0}.coverage{overflow:visible}.hero{color:#000;background:#fff}.exercise{break-inside:avoid}.transfer-exercise{border-top:2px solid #444}}