:root{color-scheme:dark;--bg:#0b1214;--panel:#101b1e;--line:#293b3e;--ink:#ecf1e9;--muted:#a8bcba;--accent:#82e5c3;--copper:#e7ae7f;--mono:'JetBrains Mono',monospace}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:400 15px/1.6 'Outfit',sans-serif}a{color:inherit;text-decoration:none}button{font:inherit;color:var(--ink);background:#18282b;border:1px solid var(--line);border-radius:7px;padding:8px 12px;cursor:pointer;touch-action:manipulation}button:hover{border-color:var(--accent)}button:focus-visible,a:focus-visible,summary:focus-visible{outline:2px solid var(--accent);outline-offset:4px}.topbar{height:56px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line);padding:0 4vw;font-size:12px;color:var(--muted)}.brand{font-size:11px;letter-spacing:.1em;color:var(--ink)}.brand span{color:var(--accent)}main{max-width:1320px;margin:auto;padding:0 32px}.intro{display:flex;justify-content:space-between;align-items:center;gap:30px;padding:22px 0}.eyebrow{font:10px var(--mono);letter-spacing:.08em;color:var(--accent);margin:0 0 10px}h1{font-size:29px;letter-spacing:-.035em;font-weight:500;margin:0;line-height:1.2}.intro>p{font-size:14px;color:var(--muted);margin:0}.model-nav{display:grid;grid-template-columns:repeat(2,1fr);border:1px solid var(--line);border-radius:10px;overflow:hidden;margin-bottom:18px}.model-tab{text-align:left;border:0;border-right:1px solid var(--line);border-radius:0;background:transparent;padding:12px 18px}.model-tab:last-child{border-right:0}.model-tab strong{font-weight:500;display:block;font-size:16px}.model-tab span{font-size:12px;color:var(--muted)}.model-tab[aria-pressed=true]{background:#1a302e;box-shadow:inset 0 -2px var(--accent)}.lab{border:1px solid var(--line);border-radius:14px;background:var(--panel);overflow:hidden}.lab-header{display:flex;justify-content:space-between;align-items:center;gap:20px;padding:18px 24px;border-bottom:1px solid var(--line)}h2{font-size:22px;font-weight:500;margin:0;letter-spacing:-.02em}.lab-header p{font-size:13px;color:var(--muted);margin:2px 0 0}.transport{display:flex;gap:8px;flex-wrap:wrap}.transport button{font-size:12px}.progress{position:relative;display:flex;justify-content:space-between;padding:12px 24px;color:var(--muted);font:10px var(--mono)}#run-state{color:var(--accent);font-size:9px}.progress-track{position:absolute;bottom:0;left:0;width:100%;height:2px;background:#213433}#progress-fill{height:100%;background:var(--accent)}.narration{display:flex;gap:15px;align-items:center;padding:18px 24px;min-height:105px;background:#142325}.narration>span{flex-shrink:0;display:grid;place-items:center;width:36px;height:36px;border:1px solid var(--accent);border-radius:50%;color:var(--accent);font:18px var(--mono)}h3{font-size:18px;font-weight:500;margin:0 0 4px}.narration p{font-size:14px;color:var(--muted);margin:0;max-width:950px}.diagram-wrap{background:#0d171a;padding:0 20px}#neuron{display:block;width:100%;max-height:300px}.wires{fill:none;stroke:#557772;stroke-width:2}.input-node circle{fill:#14282a;stroke:#6b9b90;stroke-width:1.5}.number{text-anchor:middle;fill:var(--ink);font:26px var(--mono)}.label{text-anchor:middle;fill:var(--muted);font:12px var(--mono)}.sum-node{fill:#18302f;stroke:var(--accent);stroke-width:1.5}#sum-halo{fill:none;stroke:#3b655e;stroke-dasharray:4 8}.rule-label{text-anchor:middle;fill:var(--ink);font:13px 'Outfit',sans-serif}#rule-box{fill:#1b292b;stroke:#58766e}#output-node{fill:#162625;stroke:#557772}#sum-halo.active,#rule-box.active,#output-node.active{stroke:var(--accent);stroke-width:3}#output-node.active{fill:#28483d}#moving-values rect{fill:#82e5c3;stroke:#0d171a;stroke-width:3}#moving-values text{fill:#0b1b17;font:19px var(--mono);text-anchor:middle}.calculations{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;padding:18px 24px}.calc-card{border:1px solid var(--line);border-radius:10px;padding:16px;background:#0f1a1d;min-height:190px}.calc-card.active{border-color:var(--accent);background:#19302c;box-shadow:0 0 24px #82e5c308}.calc-card.done{border-color:#48766a}.calc-card .eyebrow{font-size:9px;line-height:1.6}.calc-card strong{display:block;font:20px/1.6 var(--mono);margin:10px 0;color:var(--ink);overflow-wrap:anywhere}.calc-card code{display:block;font:12px/1.8 var(--mono);color:var(--copper);overflow-wrap:anywhere}.calc-card p:not(.eyebrow){font-size:12px;color:var(--muted);margin:8px 0 0}#sum-result{font-size:16px}#final-value{font-size:30px;color:var(--accent)}.takeaway{display:flex;gap:20px;border-top:1px solid var(--line);padding:15px 24px;align-items:center;background:#142124}.takeaway span{font:9px var(--mono);color:var(--copper);white-space:nowrap}.takeaway p{font-size:13px;margin:0;color:var(--ink)}.below{display:grid;grid-template-columns:1fr 1fr;gap:48px;margin:20px 0 30px;color:var(--muted);font-size:13px}.below>p{margin:0}.below strong{color:var(--ink);font-weight:500}summary{cursor:pointer;color:var(--ink)}details p{line-height:1.75}details a{color:var(--accent)}footer{border-top:1px solid var(--line);margin:0 4vw;padding:20px 0;display:flex;justify-content:space-between;gap:20px;color:var(--muted);font-size:12px}footer span{font:9px var(--mono)}@media(max-width:1000px){.intro{align-items:flex-start;flex-direction:column;gap:10px}.intro br{display:none}.lab-header{align-items:flex-start;flex-direction:column;gap:12px}.calculations{grid-template-columns:repeat(2,minmax(0,1fr))}.calc-card{min-height:170px}#neuron{min-width:660px}.diagram-wrap{overflow-x:auto}.below{gap:24px}}@media(max-width:600px){main{padding:0 14px}.topbar{padding:0 16px;height:48px}.brand{font-size:9px}h1{font-size:24px}.intro{padding:18px 0}.intro .eyebrow{font-size:9px}.intro>p{font-size:13px}.model-tab{padding:12px 8px}.model-tab strong{font-size:12px}.model-tab span{display:none}.lab-header{padding:16px}.transport{gap:6px}.transport button{font-size:11px;padding:8px}.progress{padding:12px 16px;font-size:9px}#run-state{font-size:8px}.narration{padding:16px;align-items:flex-start;min-height:145px}.narration p{font-size:13px}.narration h3{font-size:16px}.diagram-wrap{padding:0}#neuron{min-width:0;max-height:none}.label{font-size:15px}.rule-label{font-size:16px}.calculations{padding:12px;gap:8px;grid-template-columns:1fr}.calc-card{min-height:0;padding:14px}.calc-card p:not(.eyebrow){font-size:13px}.calc-card code{font-size:13px}.calc-card strong{margin:5px 0}.takeaway{padding:16px;flex-direction:column;align-items:flex-start;gap:8px}.below{grid-template-columns:1fr;gap:20px}footer{flex-direction:column}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important}}
.history-section{max-width:850px;margin:32px auto 40px;border-top:1px solid var(--line);padding-top:28px}.history-section h2{font-size:25px;margin-bottom:20px}.history-section #history p{font-size:16px;line-height:1.85;color:var(--muted);margin:0 0 16px}.history-section a{font-size:13px;color:var(--accent)}.history-section .model-note{font-size:12px;color:var(--muted);border-left:2px solid var(--copper);padding-left:14px;margin-top:24px}.history-section .eyebrow{color:var(--copper)}@media(max-width:600px){.history-section h2{font-size:22px}.history-section #history p{font-size:15px}}