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.real-photo-wire,.real-photo-bend,.real-photo-led{position:absolute;z-index:3;display:block;object-fit:fill;pointer-events:none;background:transparent}.real-photo-wire.h-a{left:25.35%;top:21.25%;width:17.4%;height:1.55%}.real-photo-wire.h-b{left:25.35%;top:24.05%;width:17.4%;height:1.55%}.h-power-one{left:58.75%;top:21.25%;width:32.7%;height:1.55%}.h-power-two{left:58.75%;top:58.25%;width:32.7%;height:1.55%}.h-ground-one{left:8.7%;top:38.05%;width:34%;height:1.55%}.h-ground-two{left:8.7%;top:75.05%;width:34%;height:1.55%}.real-photo-bend.h-fa{left:34.48%;top:22%;width:8.25%;height:37%;transform:scaleX(-1);filter:hue-rotate(48deg) saturate(1.08)}.real-photo-bend.h-fb{left:37.18%;top:24.8%;width:5.55%;height:37%;transform:scaleX(-1);filter:hue-rotate(48deg) saturate(1.08)}.real-photo-bend.h-sum{left:25.35%;top:27.6%;width:17.38%;height:22.9%}.real-photo-bend.h-carry{left:25.35%;top:64.6%;width:17.38%;height:13.4%;filter:hue-rotate(-62deg) saturate(1.35)}.real-photo-led{left:6.85%;width:18.5%;height:13%;object-fit:fill}.real-photo-led.h-led-a{top:9%}.real-photo-led.h-led-b{top:11.8%;transform:translateX(-1.2%) rotate(-4deg);transform-origin:bottom right}.real-photo-led.h-led-sum{top:37.5%}.real-photo-led.h-led-carry{top:65%}.photo-label{position:absolute;z-index:5;color:#111;text-shadow:0 1px 2px #fff,0 0 4px #fff;font:800 clamp(9px,1.25vw,15px)/1 Arial,sans-serif;pointer-events:none}.h-a-label{left:31%;top:19.7%}.h-b-label{left:31%;top:25.8%}.h-fa-label{left:35%;top:52%}.h-fb-label{left:37%;top:55%}.h-sum-label{left:26%;top:48.5%}.h-carry-label{left:25%;top:76%}.h-power-label{left:86%;top:19.5%}.h-ground-label{left:11%;top:81%}.h-led-a-label{left:10%;top:7.5%}.h-led-b-label{left:10%;top:14.5%}.h-led-sum-label{left:8.5%;top:36%}.h-led-carry-label{left:7.5%;top:63.5%}.test-real-breadboard .test-led-off.real-photo-led{filter:grayscale(1) brightness(.55);opacity:.72}.test-real-breadboard .test-led-on.real-photo-led{filter:saturate(1.55) brightness(1.16) drop-shadow(0 0 9px rgba(45,255,75,.9));opacity:1}
@media(max-width:1100px){.adder-test-layout{grid-template-columns:1fr}.parts-bin{max-height:none}.adder-hero{display:none!important}}
@media(max-width:760px){.component-tray .lab3-circuits{grid-template-columns:1fr!important}.prediction-pair{grid-template-columns:1fr}.switches:has(#input-cin:not([hidden])){grid-template-columns:repeat(3,1fr)}}
.inspect-only{background:#eef4f9}.inspect-only .hero,.inspect-only .phase-nav,.inspect-only .section-title,.inspect-only .component-tray,.inspect-only .tutor,.inspect-only footer{display:none!important}.inspect-only main{max-width:850px;padding:18px;margin:auto}.inspect-only #build{display:block!important}.inspect-only .build-layout,.inspect-only .build-station{display:block}.inspect-only .bench{padding:18px}.inspect-only .board-caption{font-size:1rem}.inspect-only .adder-board{width:min(100%,720px)}
.real-photo-bend.h-carry{filter:none}.real-photo-led.h-led-b{transform:none}.inspect-only .board-caption span{display:none}
.real-photo-bend-wrap{position:absolute;z-index:3;display:block;overflow:hidden;pointer-events:none;background:transparent}.real-photo-bend-wrap img{position:absolute;left:-2.2%;top:-2.6%;width:152.5%;height:105.5%;object-fit:fill;background:transparent}.real-photo-bend-wrap.h-fa{left:34.48%;top:22%;width:8.25%;height:37%;transform:scaleX(-1);filter:hue-rotate(48deg) saturate(1.08)}.real-photo-bend-wrap.h-fb{left:37.18%;top:24.8%;width:5.55%;height:37%;transform:scaleX(-1);filter:hue-rotate(48deg) saturate(1.08)}.real-photo-bend-wrap.h-sum{left:25.35%;top:27.6%;width:17.38%;height:22.9%}.real-photo-bend-wrap.h-carry{left:25.35%;top:64.6%;width:17.38%;height:13.4%}
.real-photo-wire.h-a{left:26.17%;top:20.615%;width:12.21%;height:1.55%}.real-photo-wire.h-b{left:26.17%;top:23.383%;width:12.21%;height:1.55%}.h-power-one{left:60.64%;top:20.615%;width:29.01%;height:1.55%}.h-power-two{left:60.64%;top:56.585%;width:29.01%;height:1.55%}.h-ground-one{left:10.16%;top:37.223%;width:28.22%;height:1.55%}.h-ground-two{left:10.16%;top:73.193%;width:28.22%;height:1.55%}.real-photo-bend-wrap.h-fa{left:34.47%;top:21.39%;width:3.91%;height:35.97%}.real-photo-bend-wrap.h-fb{left:30.47%;top:24.158%;width:7.91%;height:35.97%}.real-photo-bend-wrap.h-sum{left:26.17%;top:26.926%;width:12.21%;height:24.834%}.real-photo-bend-wrap.h-carry{left:26.17%;top:62.896%;width:12.21%;height:16.594%}.real-photo-led{left:9.80%;width:16.56%;height:13%}.real-photo-led.h-led-a{top:8.39%}.real-photo-led.h-led-b{top:11.158%}.real-photo-led.h-led-sum{top:38.76%}.real-photo-led.h-led-carry{top:66.49%}.h-a-label{left:31%;top:19.2%}.h-b-label{left:31%;top:24.9%}.h-sum-label{left:27%;top:50.1%}.h-carry-label{left:27%;top:77.9%}.h-power-label{left:86%;top:19.1%}.h-ground-label{left:11%;top:80.7%}
.fanout-wire{z-index:4;filter:drop-shadow(1px 2px 1px rgba(0,0,0,.24))}.fanout-wire .adder-wire{stroke-width:9.5}.fanout-wire .adder-wire-shadow{stroke-width:13;stroke:rgba(0,0,0,.28);transform:translate(1.5px,2px)}.fanout-casing{fill:none;stroke:#064f32;stroke-width:10.5;stroke-linecap:round;stroke-linejoin:round}.fanout-lowlight,.fanout-highlight{display:none}
.wire-metal-tip{fill:none;stroke-width:8;stroke-linecap:round;stroke-linejoin:round}.wire-tip-hole{stroke:#454845;stroke-width:1.5}
.photo-wire-texture,.photo-wire-corner,.photo-wire-tip{overflow:hidden}.green-photo-source{filter:hue-rotate(-72deg) saturate(1.12) brightness(.92)}.green-corner-source{filter:saturate(1.04) brightness(.92)}
.photo-wire-tip image{filter:grayscale(.35) brightness(1.12) contrast(1.18)}
.real-photo-led.h-led-a{left:7.73%;top:11.158%;height:13%;clip-path:polygon(15% 0,100% 0,100% 78.71%,84% 78.71%,84% 100%,15% 100%)}
.real-photo-led.h-led-b{left:7.73%;top:16.694%;height:13%;clip-path:polygon(15% 0,100% 0,100% 57.42%,84% 57.42%,84% 100%,15% 100%)}
.led-return-bend{position:absolute;z-index:4;left:10.02%;width:.55%;border-radius:5px;background:linear-gradient(90deg,#050606,#2d3031 48%,#090a0a);box-shadow:1px 1px 2px rgba(0,0,0,.3);pointer-events:none}
.h-led-a-return-bend{top:20.90%;height:.49%}.h-led-b-return-bend{top:26.44%;height:.49%}
.led-black-extension{position:absolute;z-index:4;left:18.05%;width:2.08%;height:.66%;border-radius:999px;background:linear-gradient(180deg,#303334 0%,#090a0a 38%,#020303 72%,#252829 100%);box-shadow:0 1px 1px rgba(0,0,0,.32);pointer-events:none}.led-black-extension::after{content:"";position:absolute;right:0;bottom:28%;width:31%;height:330%;border-radius:999px;background:linear-gradient(90deg,#303334 0%,#090a0a 42%,#020303 72%,#252829 100%);box-shadow:1px 0 1px rgba(0,0,0,.28)}.h-led-a-black-extension{top:20.57%}.h-led-b-black-extension{top:26.11%}
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.led-black-photo-extension{z-index:5;filter:contrast(1.03)}
.h-led-b-black-photo-extension{z-index:7;filter:none}
.real-photo-led.h-led-b{z-index:6}
.led-a-continuous-return{z-index:5}.led-b-continuous-return{z-index:7}.led-a-continuous-return path,.led-b-continuous-return path{fill:none;stroke-linecap:round;stroke-linejoin:round}.led-continuous-return-shadow{stroke:rgba(0,0,0,.34);stroke-width:10;transform:translate(1px,1.6px)}.led-continuous-return-wire{stroke-width:7.2}.led-continuous-return-highlight{stroke:rgba(255,255,255,.24);stroke-width:1.25}
.h-ground-upper-label{left:11%;top:35.2%}.h-power-lower-label{left:86%;top:55.1%}
.h-power-one,.h-power-two{width:33.60%}
.real-photo-led.h-led-sum{left:6.47%;clip-path:polygon(22.3% 0,100% 0,100% 78.46%,84% 78.46%,84% 100%,22.3% 100%)}
.real-photo-led.h-led-carry{left:10.205%}
.carry-led-black-extension{position:absolute;z-index:4;left:20.78%;top:76.055%;width:.405%;height:.673%;border-radius:0 5px 5px 0;background:linear-gradient(#303434 0%,#111313 31%,#020303 67%,#252828 100%);box-shadow:0 1px 2px rgba(0,0,0,.42);pointer-events:none}
.carry-led-right-metal-extension{position:absolute;z-index:3;left:25.49%;top:79.49%;width:.28%;height:.277%;background:linear-gradient(90deg,#69665f 0%,#f4eee1 42%,#817d73 78%,#4b4944 100%);box-shadow:1px 0 1px rgba(0,0,0,.3);pointer-events:none}
.h-a-label{top:17.816%}.h-b-label{left:26.2%;top:25.1%}
.h-fa-label{left:38.125%;top:51.9%}.h-fb-label{left:27.688%;top:54.8%}
.h-sum-label{left:18.9%;top:30.532%}
.h-carry-label{left:20.925%;top:62.676%}
.h-ground-label{top:70.5%}
.large-adder .diagram-input-labels text{fill:#075f91;font-size:15px}
.large-adder .diagram-junction{fill:#0878a9;stroke:none}
.large-adder .diagram-bridge-clear{fill:none;stroke:#f8fbff;stroke-width:11;stroke-linecap:round;stroke-linejoin:round}
.practice-feedback.correct{background:#e5f8f1;color:#087052}.practice-feedback.wrong{background:#fff0ee;color:#942e27}.answer:disabled{cursor:default;opacity:.72}.practice-card .equation-cards{margin:18px 0}
.real-photo-wire.f-a{left:26.17%;top:9.225%;width:12.21%;height:1.55%}.real-photo-wire.f-b{left:26.17%;top:12.025%;width:12.21%;height:1.55%}.real-photo-wire.f-cin{left:26.17%;top:20.425%;width:12.21%;height:1.55%}
.real-photo-wire.f-power-one,.real-photo-wire.f-power-two,.real-photo-wire.f-power-three{left:60.64%;width:33.60%;height:1.55%}.real-photo-wire.f-power-one{top:9.225%}.real-photo-wire.f-power-two{top:36.825%}.real-photo-wire.f-power-three{top:64.565%}
.real-photo-wire.f-ground-one,.real-photo-wire.f-ground-two,.real-photo-wire.f-ground-three{left:10.16%;width:28.22%;height:1.55%}.real-photo-wire.f-ground-one{top:26.025%}.real-photo-wire.f-ground-two{top:53.625%}.real-photo-wire.f-ground-three{top:81.365%}
.real-photo-led.f-led-a,.real-photo-led.f-led-b,.real-photo-led.f-led-cin,.real-photo-led.f-led-sum,.real-photo-led.f-led-cout{left:8.5%;width:14%;height:10.5%}.real-photo-led.f-led-a{top:.5%}.real-photo-led.f-led-b{top:7.5%}.real-photo-led.f-led-cin{left:8.89%;top:12.9%}.real-photo-led.f-led-sum{left:9.28%;top:24.1%}.real-photo-led.f-led-cout{left:8.89%;top:71.4%}
.f-led-cin-composite{overflow:visible}.f-led-cin-composite>img{position:absolute;inset:0;width:100%;height:100%;object-fit:fill;background:transparent}.f-led-cin-lower{clip-path:polygon(5.6% 34%,100% 34%,100% 86.67%,86% 86.67%,86% 100%,5.6% 100%)}.f-led-cin-bulb{clip-path:polygon(0 0,100% 0,100% 40%,0 40%);transform:translateY(26.67%)}
.f-led-cin-black-down{display:none}.f-led-cin-left-metal-tip{position:absolute;z-index:9;left:9.56%;top:20.56%;width:.82%;height:.56%;border-radius:999px;background:linear-gradient(180deg,#9a978f 0%,#fffdf7 38%,#d8d4cb 68%,#88847c 100%);pointer-events:none}
.photo-label{font-size:clamp(7.2px,1vw,12px);font-weight:400}.adder-chip-name{font-size:.496rem;font-weight:400}.f-sum-label{left:17.2%;top:36.2%}.f-fcin-label{left:34.8%}.f-x-label{left:41.35%}
.f-a-label{left:31%;top:7.4%}.f-b-label{left:30.61%;top:10.48%}.f-cin-label{left:29%;top:18.6%}.f-fa-label{left:35.05%;top:34.8%}.f-fb-label{left:32%;top:37.6%}.f-fcin-label{left:27%;top:46%}.f-x-label{left:35.5%;top:15.8%}.f-sum-label{left:25%;top:27.8%}.f-c1-label{left:36%;top:65.2%}.f-c2-label{left:32%;top:68%}.f-cout-label{left:24%;top:76.4%}
.f-power-one-label,.f-power-two-label,.f-power-three-label{left:86%}.f-power-one-label{top:7.4%}.f-power-two-label{top:35%}.f-power-three-label{top:62.74%}.f-ground-one-label,.f-ground-two-label,.f-ground-three-label{left:11%}.f-ground-one-label{top:23.6%}.f-ground-two-label{top:51.2%}.f-ground-three-label{top:79.22%}
.f-led-a-label,.f-led-b-label,.f-led-cin-label,.f-led-sum-label,.f-led-cout-label{display:none}
.f-fcin-label{left:34.8%}.f-x-label{left:41.35%}.f-sum-label{left:19.15%;top:35.64%}
.real-photo-led.f-led-a{left:9.28%;top:.22%;clip-path:polygon(2.8% 0,100% 0,100% 100%,2.8% 100%)}.real-photo-led.f-led-b{left:9.28%;top:4.7%}.f-led-b-composite{overflow:visible}.f-led-b-composite>img{position:absolute;inset:0;width:100%;height:100%;object-fit:fill;background:transparent}.f-led-b-lower-left{clip-path:polygon(2.8% 34%,87% 34%,87% 100%,2.8% 100%)}.f-led-b-lower-right{clip-path:polygon(87% 34%,100% 34%,100% 73.33%,87% 73.33%)}.f-led-b-bulb{clip-path:polygon(0 0,100% 0,100% 40%,0 40%);transform:translateY(26.67%)}.f-led-b-left-metal-tip{position:absolute;z-index:6;left:9.67%;top:12.38%;width:.65%;height:.42%;border-radius:999px;background:linear-gradient(180deg,#77746c 0%,#f6f0e5 40%,#8d897f 72%,#514f49 100%);box-shadow:0 1px 1px rgba(0,0,0,.3);pointer-events:none}.f-led-b-right-metal-cap{position:absolute;z-index:6;left:21.94%;top:12.2%;width:.42%;height:.42%;border-radius:999px;background:linear-gradient(90deg,#68665f,#f5eee2 45%,#77736a);box-shadow:0 1px 1px rgba(0,0,0,.25);pointer-events:none}.f-x-label{left:39.4%}
.f-led-cout-composite{overflow:visible}.f-led-cout-composite>img{position:absolute;inset:0;width:100%;height:100%;object-fit:fill;background:transparent;clip-path:polygon(0 0,100% 0,100% 76%,86% 76%,86% 100%,0 100%)}
.f-led-sum-right-metal-extension{position:absolute;z-index:4;left:22.12%;top:34.6%;width:.42%;height:.56%;border-radius:0 0 999px 999px;background:linear-gradient(90deg,#77736b 0%,#fffdf6 42%,#d2cec5 70%,#6f6b64 100%);box-shadow:1px 0 1px rgba(0,0,0,.24);pointer-events:none}
.f-ground-three-routed{z-index:4}.ground-three-shadow,.ground-three-wire,.ground-three-highlight,.ground-three-metal,.ground-three-metal-highlight{fill:none;stroke-linecap:round;stroke-linejoin:round}.ground-three-shadow{stroke:rgba(0,0,0,.32);stroke-width:12;transform:translate(1.2px,1.7px)}.ground-three-wire{stroke:url(#ground-three-black);stroke-width:9}.ground-three-highlight{stroke:rgba(255,255,255,.2);stroke-width:1.4}.ground-three-metal{stroke:#d8d5cd;stroke-width:7}.ground-three-metal-highlight{stroke:rgba(255,255,255,.82);stroke-width:1.5}
.f-fcin-label{left:29.925%;top:47.4%}
.f-cin-label{left:23.15%}
.f-x-and-label{left:27.8%;top:40.3%}
.f-c1-label{left:29.45%;top:62.4%}
.f-c2-label{left:37.07%;top:58.2%}