.level-card:after{border:2px dashed var(--accent);border-radius:14px;width:128px;height:78px;bottom:-30px;right:-26px}.level-card:before{content:"";background:var(--accent);opacity:.3;pointer-events:none;border-radius:3px;width:16px;height:10px;position:absolute;bottom:40px;right:60px}.level-card.check-link:before{display:none}.ex-figure{background:#0b1222;border-color:#1e293b}.note-diagram:has(svg.example-art){background:#0b1222;border-color:#1e293b;padding:0;overflow:hidden}.ex-legend i{background:var(--c);border:0;border-radius:2px;height:3px}.ex-legend i.dashed{background:repeating-linear-gradient(90deg, var(--c) 0 5px, transparent 5px 8px)}.c2 .palette{scrollbar-width:none;gap:6px;min-width:0;padding:2px;display:flex;overflow-x:auto}.c2 .palette::-webkit-scrollbar{display:none}.part-btn{border:1.5px solid var(--line);max-width:116px;min-height:54px;color:var(--ink);font:inherit;cursor:pointer;touch-action:manipulation;background:#fff;border-radius:14px;flex-direction:column;flex:1 0 64px;justify-content:center;align-items:center;gap:3px;padding:6px 6px 5px;font-size:12px;font-weight:700;transition:border-color .12s,background .12s,transform 80ms;display:flex;position:relative}.part-btn:hover{border-color:#fcd34d}.part-btn:active{transform:translateY(1px)}.part-btn[aria-checked=true]{background:#fffbeb;border-color:#f59e0b;box-shadow:0 0 0 2px #fde68a}.part-btn[data-kind=eraser][aria-checked=true]{background:#fff1f2;border-color:#e11d48;box-shadow:0 0 0 2px #fecdd3}.part-btn[data-kind=red][aria-checked=true]{background:#fef2f2;border-color:#dc2626;box-shadow:0 0 0 2px #fecaca}.part-btn[data-kind=black][aria-checked=true]{background:#f1f5f9;border-color:#0f172a;box-shadow:0 0 0 2px #cbd5e1}.part-btn[data-kind=sigma][aria-checked=true]{background:#f5f3ff;border-color:#7c3aed;box-shadow:0 0 0 2px #ddd6fe}.part-btn[data-empty]{opacity:.5}.part-icon{line-height:0;display:block}.part-name{white-space:nowrap;line-height:1.1}.part-count{color:var(--muted);font-variant-numeric:tabular-nums;font-size:12px;font-weight:800;position:absolute;top:3px;right:6px}.part-btn[data-empty] .part-count{color:var(--bad)}.c2-seg{align-items:center;gap:10px;min-width:0;display:flex}.c2-seg-k{letter-spacing:.06em;text-transform:uppercase;color:var(--muted);flex:none;font-size:12px;font-weight:800}.c2-seg .segmented{flex:auto;grid-auto-columns:1fr;grid-auto-flow:column;min-width:0;max-width:480px;display:grid}.c2-seg .seg{min-height:36px;padding:8px 10px;font-size:13px}.c2-card{z-index:4;top:var(--hud-top,86px);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);min-width:190px;max-width:min(330px,100% - 24px);box-shadow:var(--shadow);color:#e2e8f0;pointer-events:none;background:#0f172adb;border:1px solid #94a3b847;border-radius:16px;padding:8px 13px 9px;position:absolute;left:12px}.c2-card-k{letter-spacing:.08em;text-transform:uppercase;color:#94a3b8;margin:0 0 2px 1px;font-size:12px;font-weight:800}.c2-card .goal-line{color:#cbd5e1;align-items:center;gap:7px;padding:2px 0;font-size:13px;font-weight:650;line-height:1.3;display:flex}.c2-card .goal-mark{color:#fff;border:2px solid #64748b;border-radius:50%;flex:none;place-items:center;width:17px;height:17px;transition:background .2s,border-color .2s;display:grid}.c2-card .goal-mark .icon{stroke-width:3.2px}.c2-card .goal-line.ok{color:#f1f5f9}.c2-card .goal-line.ok .goal-mark{background:var(--good);border-color:var(--good)}.c2-row{flex-wrap:wrap;align-items:baseline;gap:1px 9px;margin-top:2px;display:flex}.c2-label{letter-spacing:.06em;text-transform:uppercase;color:#94a3b8;font-size:12px;font-weight:800}.c2-val{font-variant-numeric:tabular-nums;color:#f1f5f9;font-size:13.5px;font-weight:700}.c2-row.main .c2-val{font-family:var(--display);font-size:19px;font-weight:600}.c2-row.minor .c2-val{color:#cbd5e1;font-size:12px;font-weight:600}.c2-chart{width:220px;max-width:100%;margin-top:5px}.c2-chart svg{font-family:var(--font);display:block}.c2[data-mode=build] .coach,.c2[data-mode=lab] .coach{height:calc(var(--coach-lines,2) * 1.4em + 20px);scrollbar-width:thin;overflow-y:auto}.c2[data-mode=build] .dock,.c2[data-mode=lab] .dock{grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:8px 10px;display:grid}.c2[data-mode] .dock>.coach,.c2[data-mode] .dock>.choices,.c2[data-mode] .dock>.c2-seg{grid-column:1/-1}.c2[data-mode=lab] .controls{align-items:center}.c2[data-mode=lab] .param{flex:0 200px;min-width:170px}.c2 .param[data-key=ohms],.c2 .param[data-key=rheo]{--track-fill:#a16207}.c2 .param[data-key=volts],.c2 .param[data-key=E]{--track-fill:#16a34a}.c2 .param[data-key=r]{--track-fill:#ca8a04}.c2 .param[data-key=length],.c2 .param[data-key=area]{--track-fill:#ea580c}.c2 .param[data-key=answer]{--track-fill:var(--predict);background:#eef2ff;border-color:#c7d2fe}.c2 .launch[data-power]{min-width:0;margin-bottom:5px;padding:6px 16px;font-size:18px}.c2 .launch[data-power=on]{background:linear-gradient(#4ade80,#16a34a);box-shadow:0 5px #15803d,0 12px 24px -10px #16a34ab3}.c2 .launch[data-power=on]:hover{background:linear-gradient(#86efac,#22c55e)}.c2 .launch[data-power=on]:active{box-shadow:0 1px #15803d}.c2 .choices{grid-template-columns:repeat(auto-fit,minmax(150px,1fr))}@media not all and (orientation:landscape) and (height<=500px){:is(.c2[data-mode=predict] .controls:not(:has(.param:not([hidden]))) .launch,.c2[data-mode=walk] .controls:not(:has(.param:not([hidden]))) .launch){flex:auto}}.c2-title .world{opacity:.95}@media (width<=900px){.c2[data-mode=lab] .dock{grid-template-columns:minmax(0,1fr)}.c2[data-mode=lab] .controls{flex-wrap:wrap}.c2[data-mode=lab] .param{flex:150px;min-width:0}.c2[data-mode=lab] .launch[data-power]{flex:none;margin-left:auto}}@media (width<=520px) and (orientation:portrait){.part-btn{flex:1 1 0;min-width:44px;min-height:50px;padding:5px 2px 4px;font-size:12px}.part-count{font-size:12px;right:4px}.c2[data-mode=lab] .palette{flex-wrap:wrap;overflow:visible}.c2[data-mode=lab] .part-btn{flex:1 0 calc(20% - 6px);max-width:none;min-height:46px}.c2[data-mode=lab] .part-name{font-size:12px}.c2 .param{flex:130px;padding:6px 8px 4px 10px}.c2 .param-value{font-size:19px}.c2 .launch[data-power]{flex:none;min-width:54px;min-height:46px;padding:6px 12px}.c2[data-mode=build] .launch[data-power] .launch-label,.c2[data-mode=lab] .launch[data-power] .launch-label{clip-path:inset(50%);white-space:nowrap;width:1px;height:1px;position:absolute;overflow:hidden}.c2 .coach{font-size:13px;line-height:1.34}.c2[data-mode=build],.c2[data-mode=lab]{--coach-lines:3}.c2 .choice{padding:6px 9px;font-size:13px}.c2-seg .seg{min-height:34px;padding:6px}.c2-card{min-width:0;padding:6px 10px 7px}.c2-card .goal-line{padding:1px 0;font-size:12px}.c2-card .goal-mark{width:15px;height:15px}.c2-row.main .c2-val{font-size:16px}.c2-row.minor{display:none}.c2-chart{width:180px}}@media (height<=700px) and (orientation:portrait){.c2 .choices[data-resolved] .choice:not([data-correct]):not([data-wrong]){display:none}}@media (height<=600px) and (orientation:portrait){.c2-card-k{display:none}.c2 .dock{gap:6px;padding:8px 10px 10px}.c2 .launch{min-height:44px;margin-bottom:4px}.c2 .param{padding:4px 8px 2px 10px}.c2 .param-value{font-size:17px}.c2 .step{width:28px;height:28px}.c2-seg .seg{min-height:32px;padding:5px 6px}.c2-seg-k{display:none}.c2-chart{width:150px}.c2-chart svg{height:48px}.c2 .coach{font-size:12.5px}}@media (orientation:landscape) and (height<=500px){.c2[data-mode] .dock{flex-direction:column;align-items:stretch;display:flex}.c2 .palette{flex-wrap:wrap;flex:none;overflow:visible}.c2 .part-btn{flex:1 0 calc(33.3% - 6px);max-width:none;min-height:42px;padding:3px;font-size:12px}.c2[data-mode=lab] .part-btn{flex:1 0 calc(20% - 6px);min-width:0;min-height:38px;padding:3px 0}.c2[data-mode=lab] .part-name{clip-path:inset(50%);white-space:nowrap;width:1px;height:1px;position:absolute;overflow:hidden}.c2[data-mode=build],.c2[data-mode=lab]{--coach-lines:4}.c2[data-mode] .controls .launch{flex:none}.c2 .choices[data-resolved] .choice:not([data-correct]):not([data-wrong]){display:none}.c2[data-mode=lab] .param{flex:none;min-width:0}.c2 .launch[data-power]{margin-left:0}.c2-seg{gap:6px}.c2-seg-k{display:none}.c2-seg .seg{min-height:32px;padding:5px 4px;font-size:12px}.c2-card{min-width:0;max-width:240px;padding:5px 9px 6px;left:6px}.c2-card-k{display:none}.c2-card .goal-line{padding:1px 0;font-size:12px}.c2-card .goal-mark{width:14px;height:14px}.c2-row.main .c2-val{font-size:15px}.c2-row.minor{display:none}.c2-chart{width:160px}.c2-chart svg{height:54px}}