:root{--paper:#f7f5ee;--card:#fffdf8;--ink:#24333c;--muted:#6f7779;--line:#dcded8;--accent:#6852a2;--soft:#ebe6f4;--orange:#c57443;--green:#587564;--navy:#1e303c;--serif:Georgia,'Times New Roman',serif;--sans:ui-sans-serif,-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:14px/1.6 var(--sans)}button,input,select{font:inherit;color:inherit}button,a{touch-action:manipulation}button{cursor:pointer;transition:background-color .15s,scale .08s}button:active{scale:.96}button:disabled{cursor:default;opacity:.5;scale:1}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,[tabindex]:focus-visible{outline:3px solid var(--orange);outline-offset:4px}a{color:inherit;text-underline-offset:4px}header{display:flex;gap:20px;align-items:center;justify-content:space-between;padding:17px 3vw;border-bottom:1px solid var(--line)}.brand{font:23px var(--serif);text-decoration:none}.brand 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20px;font-size:9px;text-transform:uppercase;letter-spacing:.14em;color:#a5bcc6}.board svg{display:block;width:100%;height:auto;user-select:none}.board-foot{border-top:1px solid #3a4a55;margin:0 19px;padding:12px 0;font-size:10px;color:#a4b7bf;display:flex;gap:12px;justify-content:space-between;flex-wrap:wrap}.wire{stroke:#94adba;stroke-width:2.5;fill:none}.part{transition:stroke .15s;cursor:pointer}.part.hot{stroke:#e9bb71!important;filter:drop-shadow(0 0 4px #e9bb7160)}.node{cursor:pointer;outline:none}.node:focus circle,.node:hover circle{stroke:#e8c585;stroke-width:4}.probe{cursor:grab;touch-action:none}.probe:active{cursor:grabbing}.meter{background:#ecede4;border:1px solid var(--line);border-radius:8px;padding:16px 20px;margin-top:12px;display:flex;justify-content:space-between;gap:15px;align-items:center}.meter strong{font:34px ui-monospace,monospace;letter-spacing:-.04em}.meter .eyebrow{color:var(--muted)}.meter 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var(--accent);border-radius:3px;background:var(--card)}[hidden]{display:none!important}.hint-line{font-size:10px;color:var(--muted);margin-top:12px}.equation{display:flex;gap:7px;align-items:center;flex-wrap:wrap;font:24px/1.5 var(--serif);margin:16px 0}.term{border:1px solid var(--line);background:var(--card);border-radius:5px;padding:7px 11px;min-height:44px;font:inherit}.term.hot,.term:hover{background:#f6e9d5;border-color:#d4b785}.term small{font:9px var(--sans);display:block;color:var(--muted)}.formula{font:23px/1.5 var(--serif);padding:14px 16px;background:#eeedf4;border-radius:6px;margin:16px 0}.formula small{display:block;font:11px/1.6 var(--sans);color:var(--muted);margin-top:8px}.potential{border-top:1px solid var(--line);margin-top:20px;padding-top:17px}.potential svg{width:100%;height:auto;display:block}.legend{font-size:10px;display:flex;gap:15px;flex-wrap:wrap}.legend i{width:18px;height:2px;display:inline-block;vertical-align:middle;background:var(--accent);margin-right:5px}.legend i.before{background:var(--orange)}.companion{display:flex;gap:12px;border-bottom:1px solid var(--line);padding-bottom:18px;margin-bottom:22px}.avatar{flex:0 0 33px;height:36px;background:#d9cbe7;border:1px solid #b9a6ce;border-radius:50% 50% 35% 35%;display:grid;place-items:center;font:19px var(--serif);color:#766086}.companion p{font:17px/1.5 var(--serif);margin:5px 0 0}.choices{display:grid;gap:8px;margin:16px 0}.choices .btn{text-align:left}.feedback{padding:15px;border-left:3px solid var(--accent);background:var(--soft);font-size:12px;margin:16px 0}.feedback.good{border-color:var(--green);background:#e7efe7}.feedback.warm{border-color:var(--orange);background:#f2e5d8}.status{min-height:20px;font-size:11px;color:var(--accent);margin-top:10px}.journey-next{display:flex;align-items:center;justify-content:space-between;gap:16px;border-top:1px solid var(--line);margin-top:25px;padding-top:20px}.traversal{display:flex;gap:7px;flex-wrap:wrap;margin:18px 0}.traversal button{font:12px ui-monospace,monospace}.switch-row{display:flex;gap:10px;align-items:center}.switch-row input{accent-color:var(--accent);width:18px;height:18px}.summary-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:20px 0}.summary-grid div{border-top:1px solid var(--line);padding-top:10px}.summary-grid strong{display:block;font:24px var(--serif)}.summary-grid > div > span{font-size:10px;color:var(--muted)}.trail{display:flex;align-items:center;gap:8px;flex-wrap:wrap;font-size:11px}.dot{display:inline-block;width:7px;height:7px;border-radius:50%;background:var(--accent)}.tabs{display:flex;gap:5px;flex-wrap:wrap;margin:14px 0 22px}.tabs button{background:none;border:1px solid transparent;border-radius:5px;min-height:44px;padding:10px 13px;font-size:12px}.tabs button[aria-pressed=true]{background:var(--ink);color:var(--card)}input[type=range]{width:100%;accent-color:var(--accent);min-height:35px}label.caption{display:block;font-size:11px;margin:15px 0 6px}select{background:var(--card);border:1px solid var(--line);padding:10px;border-radius:5px;max-width:100%;font-size:12px}.answer-line{display:flex;gap:10px;align-items:center;margin:18px 0}.answer-line input{width:140px;min-width:0;background:var(--card);border:1px solid #bcb1cf;border-radius:5px;padding:12px;font:25px ui-monospace,monospace}.answer-line span{font-size:12px}.quiet-surface{background:repeating-linear-gradient(0deg,transparent,transparent 28px,#e4e2db 29px),var(--card);border:1px solid var(--line);border-radius:8px;padding:25px;min-height:155px}.test-progress{display:flex;gap:5px;margin:20px 0}.test-progress span{height:4px;flex:1;background:var(--line)}.test-progress .done{background:var(--accent)}.result-row{padding:15px 0;border-bottom:1px solid var(--line);font-size:12px}.result-row strong{display:block}.correct{color:#52745d}.incorrect{color:#ab6444}.score{font:66px var(--serif);letter-spacing:-.05em;margin:15px 0}.review-ledger{max-height:400px;overflow:auto}.review-ledger article{padding:13px 0;border-bottom:1px solid var(--line);font-size:12px}.review-ledger small{display:block;color:var(--muted)}details{font-size:11px;margin-top:20px;border-top:1px solid var(--line);padding-top:14px}summary{cursor:pointer;min-height:34px}footer{display:flex;justify-content:space-between;gap:20px;padding:18px 3vw;border-top:1px solid var(--line);font-size:10px;color:var(--muted)}dialog{max-width:700px;width:calc(100% - 40px);max-height:85vh;overflow:auto;padding:25px;border:1px solid var(--line);border-radius:12px;color:var(--ink);background:var(--card)}dialog::backdrop{background:#1c2b3755}.skip{position:fixed;top:-100px;left:20px;background:var(--card);padding:12px;z-index:5}.skip:focus{top:10px}.sr{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.flow-on .current-path{animation:current 2s linear infinite}@keyframes current{to{stroke-dashoffset:-30}}.current-path{stroke:#dac792;stroke-dasharray:3 12;fill:none;pointer-events:none}
@media(min-width:1600px){main{padding:45px 45px 70px}.workspace{gap:28px}}
@media(max-width:1150px){.app{grid-template-columns:175px minmax(0,1fr)}.rail{padding:30px 13px}.workspace{grid-template-columns:minmax(0,1.15fr) minmax(270px,1fr)}main{padding:30px 23px 45px}.panel{padding:19px}.meter strong{font-size:28px}.edition{display:none}}
@media(max-width:950px){.workspace{grid-template-columns:1fr}.rail{padding-top:28px}.intro h1{font-size:49px}.workspace>aside{max-width:none}.reactive-prose{font-size:22px}}
@media(max-width:650px){header{padding:12px 20px}.brand{font-size:21px}.app{display:block}.rail{border-right:0;border-bottom:1px solid var(--line);padding:12px 14px}.rail-title,.rail>.eyebrow,.rail-note{display:none}nav{grid-template-columns:repeat(3,1fr);gap:4px}nav button{font-size:10px;min-height:48px;padding:8px;gap:6px}nav button small{display:none}nav button span{font-size:9px}main{padding:26px 20px 40px}.intro h1{font-size:43px}.intro p{font-size:14px}.board-head{padding:14px;font-size:8px}.board-foot{font-size:9px}.meter{padding:13px}.meter strong{font-size:27px}.summary-grid strong{font-size:23px}.equation{font-size:21px}.term{padding:6px 9px}.journey-next{align-items:start}.panel{padding:19px}.reactive-prose{font-size:21px}footer{padding:20px;display:block}footer a{display:block;margin-top:10px}}
@media(max-width:370px){main{padding:22px 14px}.meter{flex-wrap:wrap}.summary-grid{gap:5px}.intro h1{font-size:39px}.tabs button{padding:9px}.brand{font-size:19px}.rail{padding:10px}.answer-line input{width:115px}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{transition:none!important;animation:none!important}button:active{scale:1}}