.builder-section{border-top:1px solid var(--line)}.builder-shortcut{display:inline-block;color:var(--cyan);font-size:14px;margin:0 0 23px}.builder-toolbar{display:flex;align-items:flex-end;gap:14px;flex-wrap:wrap;margin-bottom:20px}.builder-toolbar label,.builder-inspector label{font-size:12px;color:var(--muted);display:block}.builder-toolbar select,.builder-toolbar input,.builder-inspector input,.builder-inspector select{display:block;background:var(--panel);color:var(--text);border:1px solid var(--line);border-radius:4px;padding:11px;margin-top:7px;font-size:14px;max-width:100%;min-width:0}.builder-toolbar input{width:110px}.builder-toolbar button,.builder-bottom button,.builder-zoom button{background:var(--panel);border:1px solid var(--line);border-radius:4px;padding:11px 14px;font-size:13px;min-height:42px}.builder-toolbar .builder-power{color:var(--acid);border-color:var(--acid);margin-left:auto}.builder-power.off{color:var(--muted);border-color:var(--line)}.builder-shell{display:grid;grid-template-columns:minmax(0,1fr) 275px;border:1px solid var(--line);border-radius:8px;overflow:hidden;background:var(--panel)}.builder-work{min-width:0;padding:22px}.builder-tools{display:flex;gap:6px;flex-wrap:wrap}.builder-tools button,.builder-palette button{border:1px solid var(--line);border-radius:4px;padding:10px 14px;background:var(--bg);font-size:13px;min-height:44px}.builder-tools .active{border-color:var(--cyan);color:var(--cyan);background:var(--panel2)}.builder-palette{display:flex;gap:6px;flex-wrap:wrap;margin-top:13px}.builder-palette button{font-size:12px;padding:9px 12px;color:var(--muted)}.builder-palette button:hover{color:var(--acid);border-color:var(--acid)}.builder-hint{font-size:12px;line-height:1.7;color:var(--muted);min-height:40px;margin:15px 0}.builder-stage{position:relative;background:var(--bg);border:1px solid var(--line);border-radius:5px;overflow:hidden}#builderCanvas{display:block;width:100%;height:auto;touch-action:none;user-select:none;max-height:750px}.builder-zoom{display:flex;gap:5px;justify-content:center;padding:9px;border-top:1px solid var(--line);background:var(--bg)}.builder-zoom button{min-width:42px;padding:8px 11px;font-size:12px}.builder-grid-dot{fill:var(--line)}.builder-part{cursor:grab;fill:var(--panel2);stroke:var(--cyan);stroke-width:2.5;outline:none}.builder-part.selected{stroke:var(--acid)}.builder-part:focus-visible{stroke:var(--orange);stroke-width:4}.builder-part text{stroke:none;fill:var(--text);font:16px var(--mono);text-anchor:middle;pointer-events:none}.builder-part .part-label{fill:var(--cyan);font-size:17px}.builder-part .part-value{fill:var(--muted);font-size:15px}.builder-part .source-letter{font-size:24px}.builder-part .part-hit{fill:transparent;stroke:none}.builder-wire{stroke:var(--cyan);stroke-width:2;fill:none;opacity:.65;pointer-events:none}.builder-wire.selected-wire{stroke:var(--acid);stroke-width:3}.builder-wire.meter-wire{stroke:var(--orange);stroke-width:3;opacity:1}.wire-arrow{fill:var(--orange)}.wire-hit{stroke:transparent;stroke-width:24;fill:none;cursor:pointer}.builder-port{fill:var(--bg);stroke:var(--cyan);stroke-width:2;pointer-events:none}.port-hit{fill:transparent;stroke:none;cursor:crosshair}.port-group:focus-visible .builder-port,.port-pending{fill:var(--acid);stroke:var(--acid)}.port-red{stroke:#ff616e;fill:#ff616e}.port-black{stroke:var(--text);fill:var(--bg)}.probe-ring{fill:none;stroke-width:2;pointer-events:none}.inline-meter{fill:var(--bg);stroke:var(--orange);stroke-width:2}.inline-meter-label{fill:var(--orange);text-anchor:middle;font:17px var(--mono);pointer-events:none}.builder-bottom{display:flex;gap:7px;align-items:center;margin-top:12px;flex-wrap:wrap}.builder-bottom button{font-size:12px;padding:8px 10px;min-height:38px}.builder-bottom span{font-size:11px;color:var(--muted);margin-left:auto}.builder-status{font-size:12px;line-height:1.6;color:var(--muted);padding:16px 0;min-height:52px;overflow-wrap:anywhere}.builder-status.fault{color:var(--orange)}.builder-metrics{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.builder-metrics>div{font:17px var(--mono);overflow-wrap:anywhere}.builder-metrics small{display:block;font:10px var(--mono);color:var(--muted);margin-bottom:8px}.builder-side{border-left:1px solid var(--line);padding:23px;min-width:0}.builder-inspector>.eyebrow{font-size:10px;margin-bottom:19px}.builder-inspector select,.builder-inspector input{width:100%;margin-bottom:16px}.builder-inspector p{font-size:12px;color:var(--muted);line-height:1.6}.virtual-meter{padding:16px;background:var(--bg);border:1px solid var(--line);border-radius:10px;margin-top:24px}.meter-top{display:flex;flex-direction:column;gap:5px;font:11px var(--mono);color:var(--muted)}.meter-top b{font-size:13px;color:var(--text);letter-spacing:1px}.meter-top span{font-size:9px}.meter-screen{background:var(--panel2);border:1px solid var(--line);border-radius:4px;padding:13px;margin:16px 0}.meter-screen>span{font:11px var(--mono);color:var(--muted);display:block}.meter-screen output{display:block;font:500 31px var(--mono);color:var(--acid);padding:16px 0;overflow-wrap:anywhere}.meter-screen #meterDetail{font:11px/1.6 var(--font);min-height:34px}.meter-modes{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}.meter-modes button{background:var(--panel);border:1px solid var(--line);border-radius:50%;height:45px;font:20px var(--mono)}.meter-modes .active{color:var(--acid);border-color:var(--acid)}.meter-probes{display:flex;gap:8px;margin-top:20px}.meter-probes[hidden]{display:none}.meter-probes button{background:var(--panel);border:1px solid var(--line);border-radius:4px;padding:10px 8px;flex:1;font:12px var(--mono);min-height:44px}.probe-red{color:#ff616e}.probe-black{color:var(--text)}.meter-probes .active{border-color:currentColor;box-shadow:inset 0 -2px currentColor}.virtual-meter p{font:12px/1.7 var(--font);color:var(--muted)}#meterClear{font-size:12px;color:var(--muted);background:none;border:1px solid var(--line);border-radius:4px;padding:8px 10px;min-height:40px}.builder-readings{font-size:13px;margin-top:22px}.builder-readings>div>div{display:grid;grid-template-columns:1fr 1fr;gap:9px;padding:15px 0;border-bottom:1px solid var(--line);font:12px var(--mono)}.builder-readings span{color:var(--muted)}.builder-model-note{font-size:12px;color:var(--muted);line-height:1.8;margin-top:24px}.calculation-stepper{border-top:1px solid var(--line);padding:18px}.calculation-stepper summary{font-size:14px;color:var(--cyan)}.step-title{font:500 22px var(--display);margin:17px 0 9px}.step-text{font:13px/1.8 var(--font);color:var(--muted);overflow-wrap:anywhere;margin:0 0 15px}.step-actions{display:flex;align-items:center;gap:8px;flex-wrap:wrap}.step-actions button{background:var(--panel);border:1px solid var(--line);border-radius:4px;padding:10px 13px;font-size:13px;min-height:44px}.step-actions button:last-child{color:var(--acid);border-color:var(--acid)}.step-counter{font:12px var(--mono);color:var(--muted);margin-right:auto}.step-focus-resistors .lab-resistor{stroke:var(--acid);stroke-width:4;filter:drop-shadow(0 0 5px #b9ff4240)}.step-focus-flow .lab-flow{stroke:var(--acid);stroke-width:4}.step-focus-reference .lab-reference{stroke:var(--acid);stroke-width:4}.step-focus-vector .lab-vector-p,.step-focus-vector .lab-vector-q,.step-focus-vector .lab-vector-s{stroke-width:5}.step-active-graphic{animation:rise .3s ease}.mobile-lab-values{display:none}
/* Simulator geometry scales to the phone; text values stay outside the SVG. */
.tool-lab-graphic svg{min-width:0;width:100%;height:auto}.tool-lab-graphic{overflow:hidden}.lab-pan-hint{display:none!important}.lab-chart svg{min-width:0;width:100%}.lab-chart{overflow:hidden}
@media(max-width:1000px){.builder-shell{grid-template-columns:minmax(0,1fr) 250px}.builder-work{padding:16px}.builder-side{padding:16px}.builder-tools button{padding:10px}.builder-toolbar .builder-power{margin-left:0}}
@media(max-width:760px){.builder-shell{grid-template-columns:minmax(0,1fr)}.builder-toolbar{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:12px;align-items:end}.builder-toolbar select,.builder-toolbar input{width:100%;font-size:16px;min-height:46px}.builder-toolbar button{font-size:13px;min-height:46px;padding:10px}.builder-work{padding:14px}.builder-tools{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:4px}.builder-tools button{font-size:12px;padding:9px 2px;min-height:46px}.builder-palette{display:grid;grid-template-columns:1fr 1fr}.builder-palette button{font-size:12px;padding:10px 6px;min-height:44px}.builder-hint{font-size:13px;line-height:1.6;min-height:62px}.builder-side{border-left:0;border-top:1px solid var(--line);display:grid;grid-template-columns:minmax(0,1fr);padding:20px}.builder-inspector select,.builder-inspector input{font-size:16px;min-height:46px}.virtual-meter{max-width:100%;margin-top:12px;padding:20px}.meter-top{flex-direction:row;align-items:center;justify-content:space-between}.meter-screen output{font-size:40px}.meter-screen #meterDetail{font-size:13px;min-height:22px}.meter-modes button{border-radius:6px;height:48px}.meter-probes button{min-height:48px;font-size:14px}.virtual-meter p{font-size:13px}.builder-bottom{display:grid;grid-template-columns:1fr 1fr}.builder-bottom button{min-height:44px}.builder-bottom span{grid-column:1/-1;text-align:center;margin:5px 0 0;font-size:11px}.builder-metrics{gap:10px;grid-template-columns:1fr}.builder-metrics>div{display:flex;justify-content:space-between;align-items:center;font-size:16px;gap:10px}.builder-metrics small{font-size:11px;margin:0}.builder-status{font-size:13px}.builder-model-note{font-size:13px}.builder-part text{font-size:18px}.builder-part .part-value{font-size:17px}.builder-part .part-label{font-size:19px}.builder-shortcut{font-size:14px;line-height:1.7}.tool-lab-graphic svg{min-height:0;max-height:none}.tool-lab svg .lab-mobile-symbol{font-size:30px;fill:var(--text)}.mobile-lab-values{display:grid;grid-template-columns:1fr 1fr;gap:10px;padding:4px 14px 12px}.mobile-lab-values>div{background:var(--panel);padding:10px;border:1px solid var(--line);border-radius:4px;min-width:0;font:14px var(--mono);overflow-wrap:anywhere}.mobile-lab-values small{display:block;font:12px/1.4 var(--font);color:var(--muted);margin-bottom:7px}.calculation-stepper{padding:15px}.step-title{font-size:23px}.step-text{font-size:14px}.step-actions{gap:6px}.step-counter{width:100%;margin-bottom:5px}.step-actions button{flex:1;padding:10px 8px;font-size:13px}.lab-controls label,.lab-adjust-label{font-size:13px}.lab-controls select,.lab-graph-details select{font-size:16px;min-height:46px}.lab-controls input[type=range]{min-height:34px}.calc-fields{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}.field,.field-control{min-width:0}.extra-results{display:grid;grid-template-columns:1fr 1fr;gap:14px}.extra-results>div{min-width:0;overflow-wrap:anywhere}.main-result{font-size:clamp(25px,8vw,37px)}.exercise-selects select{font-size:16px}.step-text,.lab-worked{overflow-wrap:anywhere}.sim-tabs{flex-wrap:wrap}.sim-control input[type=range]{min-height:34px}.calculator{padding:18px}.sim-visual{overflow:hidden}.sim-control{padding:21px}#simReadout{flex-wrap:wrap;font-size:16px;gap:14px}#simReadout>div{min-width:82px}#simReadout small{font-size:10px}.lab-chart svg .lab-small{font-size:13px}.tool-lab .lab-guidance{font-size:13px}.builder-stage svg{min-height:350px}.builder-section .section-heading h2{font-size:42px}}
/* Instrument, diagram editing and circuit workbench */
#builderCanvas{height:510px;max-height:none;min-height:0;aspect-ratio:auto}.builder-stage svg{min-height:0}.builder-part{transition:filter .2s}.builder-wire{stroke:var(--wire-color,var(--cyan));vector-effect:non-scaling-stroke}.builder-port{vector-effect:non-scaling-stroke}.wire-hit{vector-effect:non-scaling-stroke;stroke-width:18}.node-highlight .builder-wire{stroke:var(--acid);opacity:1;filter:drop-shadow(0 0 4px var(--acid))}.node-highlight .builder-port{stroke:var(--acid);fill:var(--acid)}.wire-preview{stroke:var(--acid);stroke-width:2;stroke-dasharray:7 5;fill:none;vector-effect:non-scaling-stroke}.wire-handle{fill:var(--bg);stroke:var(--acid);stroke-width:2;cursor:move;vector-effect:non-scaling-stroke}.wire-handle:focus-visible{fill:var(--acid);outline:none}.flow-particle{fill:var(--text);filter:drop-shadow(0 0 3px var(--cyan))}.power-glow{filter:drop-shadow(0 0 calc(3px + var(--heat)*9px) #ff9259)}.meter-lead{fill:none;stroke-width:3;vector-effect:non-scaling-stroke;opacity:.8;stroke-linecap:round}.meter-lead.black{stroke-dasharray:8 3}.probe-caption{fill:var(--text);stroke:none;font-family:var(--mono);font-size:10px}.builder-display{display:flex;flex-wrap:wrap;gap:12px;font-size:12px;color:var(--muted);margin:0 0 10px}.builder-display label{display:flex;align-items:center;gap:5px;min-height:34px}.builder-display input{accent-color:var(--acid);width:17px;height:17px}.builder-legend{font:11px/1.6 var(--font);color:var(--muted);min-height:34px}.parallel-choice{display:flex;align-items:center;gap:7px;font-size:11px;color:var(--muted)}.parallel-choice select{font-size:12px;color:var(--text);background:var(--bg);border:1px solid var(--line);border-radius:4px;padding:10px;min-width:0;max-width:150px}#wireEditor{display:flex;gap:7px;align-items:center;flex-wrap:wrap;padding:8px 0 14px;font-size:12px}#wireEditor[hidden]{display:none}#wireEditor button{font-size:12px;background:var(--panel2);border:1px solid var(--line);color:var(--text);padding:10px;border-radius:4px}.builder-inspector input[aria-invalid=true]{border-color:#e15c68;outline:2px solid #e15c6840}.instrument{background:linear-gradient(145deg,var(--panel2),var(--bg));border:4px solid var(--line);border-bottom-width:12px;box-shadow:inset 0 0 0 1px #ffffff12,0 12px 22px #0002;border-radius:24px 24px 30px 30px;position:relative}.instrument .meter-top{font-size:9px;letter-spacing:1px}.instrument .meter-screen{background:#d3dec0;color:#192518;border:5px solid #28322a;box-shadow:inset 0 2px 8px #0003;border-radius:8px}.instrument .meter-screen output{color:#192518;font:600 32px var(--mono);text-shadow:0 1px 0 #ffffff60}.instrument .meter-screen>span,.instrument .meter-screen #meterDetail{color:#334532}.meter-dial{height:110px;width:158px;margin:14px auto 8px;position:relative}.meter-dial>span{position:absolute;font:15px var(--mono);color:var(--muted)}.dial-v{left:12px;top:30px}.dial-a{left:73px;top:0}.dial-r{right:12px;top:30px}.dial-knob{position:absolute;left:43px;top:27px;width:74px;height:74px;background:linear-gradient(90deg,#161c21,#46545e,#1c252c);border:3px solid #52616b;border-radius:50%;box-shadow:0 5px 8px #0005;transition:transform .25s}.dial-knob:before{content:'';position:absolute;inset:10px 24px;background:#182128;border:1px solid #6f818e;border-radius:8px}.dial-knob i{position:absolute;left:30px;top:5px;width:8px;height:18px;background:var(--acid);border-radius:2px}.meter-connections{font:10px/1.6 var(--mono);color:var(--muted);overflow-wrap:anywhere;margin:12px 0}.meter-jacks{display:flex;justify-content:space-around;margin:12px 0}.jack{font-size:29px;line-height:1;text-align:center;text-shadow:0 2px 4px #0008}.jack small{display:block;font:9px var(--mono);color:var(--muted);margin-top:6px}.jack-com{color:var(--text)}.jack-red{color:#ff616e}.instrument .meter-modes button{border-radius:6px;font-size:17px;height:42px}.scope-panel{border:1px solid var(--line);border-radius:8px;padding:14px;margin-top:24px}.scope-panel summary{font:13px var(--mono);color:var(--cyan)}.scope-panel p{font-size:11px;line-height:1.6;color:var(--muted);overflow-wrap:anywhere}.scope-panel svg{display:block;width:100%;height:auto;background:var(--bg);border-radius:5px;margin:10px 0}.scope-panel svg:empty{display:none}.scope-panel text{fill:var(--muted);font:10px var(--mono)}.scope-grid{fill:none;stroke:var(--line);stroke-width:1}.scope-u{stroke:var(--cyan);stroke-width:2;fill:none}.scope-i{stroke:var(--orange);stroke-width:2;fill:none;stroke-dasharray:5 3}.scope-i-label{fill:var(--orange)!important}.phasor-dot-u{fill:var(--cyan)}.phasor-dot-i{fill:var(--orange)}.scope-cursor{stroke:var(--muted);stroke-dasharray:2 4}.circuit-library,.fault-lab{border-top:1px solid var(--line);padding:18px 0;margin-top:18px;font-size:13px}.circuit-library summary,.fault-lab summary{color:var(--cyan)}.library-controls,.fault-controls{display:flex;flex-wrap:wrap;gap:10px;align-items:flex-end;margin-top:16px}.library-controls label,.fault-controls label{display:block;color:var(--muted);font-size:12px;max-width:100%;min-width:0}.library-controls input,.library-controls select,.fault-controls select{display:block;border:1px solid var(--line);background:var(--bg);color:var(--text);padding:11px;border-radius:4px;margin-top:6px;max-width:100%;min-width:0}.library-controls button,.fault-controls button,.import-button{background:var(--panel2);border:1px solid var(--line);border-radius:4px;padding:11px;color:var(--text);min-height:44px;font-size:12px}.import-button input{font-size:11px;width:190px;padding:5px;border:0}.fault-lab p{font-size:12px;line-height:1.7;color:var(--muted)}.fault-highlight .builder-wire,.fault-highlight{stroke:var(--orange)!important;filter:drop-shadow(0 0 6px var(--orange))}#compareResults{overflow-x:auto}#compareResults table{border-collapse:collapse;width:100%;font:12px var(--mono)}#compareResults th,#compareResults td{padding:12px 8px;border-bottom:1px solid var(--line);text-align:right}#compareResults th:first-child,#compareResults td:first-child{text-align:left}#compareResults p{font-size:12px;color:var(--muted)}.builder-section:fullscreen,.builder-section.builder-fullscreen{background:var(--bg);padding:24px!important;overflow:auto;max-width:none;margin:0;}.builder-section.builder-fullscreen{position:fixed;inset:0;z-index:100}.builder-section:fullscreen .section-heading,.builder-fullscreen .section-heading{display:none}.builder-section:fullscreen #builderCanvas,.builder-fullscreen #builderCanvas{height:68vh}.builder-section:fullscreen .builder-shell,.builder-fullscreen .builder-shell{grid-template-columns:minmax(0,1fr) 310px}.tool-lab-graphic{position:relative}.result-updated .result{animation:resultFlash .45s ease-out}@keyframes resultFlash{from{box-shadow:0 0 0 2px var(--cyan);background-color:#49e2ed20}to{box-shadow:0 0 0 0 transparent}}.tool-lab-graphic .step-active-graphic{transition:transform .35s}.meter-lead,.wire-preview,.flow-particle{pointer-events:none}
@media(max-width:760px){#builderCanvas{height:430px;min-height:0}.builder-section:fullscreen .builder-shell,.builder-fullscreen .builder-shell{grid-template-columns:1fr}.builder-section:fullscreen #builderCanvas,.builder-fullscreen #builderCanvas{height:65vh}.builder-section:fullscreen,.builder-fullscreen{padding:10px!important}.builder-section:fullscreen .builder-side,.builder-fullscreen .builder-side{display:block}.builder-palette .parallel-choice{grid-column:1/-1;justify-content:space-between}.parallel-choice select{max-width:65%;font-size:16px}.builder-palette #builderParallel{grid-column:1/-1;color:var(--acid)}.builder-display{display:grid;grid-template-columns:1fr 1fr;gap:4px}.builder-display label{font-size:12px;min-height:42px}.library-controls,.fault-controls{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr)}.library-controls input,.library-controls select,.fault-controls select{width:100%;font-size:16px}.library-controls label:first-child,.fault-controls label{grid-column:1/-1}.library-controls button,.fault-controls button{min-height:46px}.instrument{max-width:360px;width:100%;margin:14px auto}.meter-dial{transform:scale(1.08);margin:24px auto 15px}.scope-panel{max-width:440px;width:100%;margin:24px auto 0}.scope-panel p{font-size:13px}.scope-panel svg{min-height:0}.builder-legend{font-size:12px}.builder-bottom span{overflow-wrap:anywhere}.builder-tools button{min-width:0}}
@media(prefers-reduced-motion:reduce){.dial-knob{transition:none}.result-updated .result{animation:none}.power-glow{filter:none}}body.reduced .result-updated .result{animation:none}body.reduced .dial-knob{transition:none}

@media(max-width:380px){.calc-fields{grid-template-columns:minmax(0,1fr)}.builder-toolbar{grid-template-columns:minmax(0,1fr)}.library-controls,.fault-controls{grid-template-columns:minmax(0,1fr)}.builder-tools button{font-size:11px}.builder-work{padding:9px}.builder-side{padding:12px}}