@import "https://fonts.googleapis.com/css2?family=Instrument+Serif&family=Instrument+Sans:wght@400;500;600&family=JetBrains+Mono:wght@400;500&display=swap";:root{--graphite:#15171c;--graphite-raised:#22262e;--graphite-hover:#1e2229;--graphite-rule:#2a2e36;--graphite-text:#a8adb8;--graphite-dim:#6e7480;--graphite-bright:#f2f3f0;--paper:#f2f3f0;--paper-raised:#f7f8f5;--ink:#1a1c20;--ink-soft:#41464e;--muted:#7b8189;--rule:#dcddd8;--rule-strong:#c9cbc6;--signal:#e3a11f;--signal-deep:#b07f14;--signal-tint:#fbf4e6;--warn:#c0584a;--warn-tint:#fbf0ee;--serif:"Instrument Serif", Georgia, serif;--sans:"Instrument Sans", system-ui, -apple-system, "Segoe UI", sans-serif;--mono:"JetBrains Mono", ui-monospace, "Cascadia Code", monospace;--rail:300px;--gutter:56px;--measure:62ch}*,:before,:after{box-sizing:border-box}html{-webkit-text-size-adjust:100%}body{background:var(--paper);color:var(--ink);font-family:var(--sans);-webkit-font-smoothing:antialiased;text-rendering:optimizelegibility;margin:0;font-size:17px;line-height:1.55}a{color:inherit;text-decoration:none}.app{min-height:100vh;display:flex}.main{min-width:0;padding:52px var(--gutter) 96px;flex:1}.prose{max-width:var(--measure)}.rail{width:var(--rail);background:var(--graphite);color:var(--graphite-text);flex-direction:column;flex:none;gap:22px;height:100vh;padding:28px 22px;display:flex;position:sticky;top:0;overflow-y:auto}.rail-brand{font-family:var(--serif);color:var(--graphite-bright);align-items:baseline;gap:8px;font-size:25px;line-height:1;display:flex}.rail-brand:after{content:"";background:var(--signal);border-radius:50%;width:6px;height:6px;display:block;transform:translateY(-2px)}.rail-block{border:1px solid var(--graphite-rule);border-radius:6px;padding:13px 14px 11px}.rail-count{font-family:var(--serif);color:var(--signal);font-size:30px;line-height:1}.rail-label{color:var(--graphite-dim);margin-top:5px;font-size:11.5px}.rail-section{border-radius:5px;justify-content:space-between;padding:7px 9px;font-size:12.5px;display:flex}.rail-section[aria-current=true]{background:var(--graphite-raised);color:var(--graphite-bright)}.rail-section span:last-child{font-family:var(--mono);color:var(--graphite-dim);font-size:10.5px}.rail-section[aria-current=true] span:last-child{color:var(--signal)}.rail-nav{border-top:1px solid var(--graphite-rule);flex-direction:column;gap:1px;padding-top:12px;display:flex}.rail-link{color:var(--graphite-text);border-radius:5px;align-items:center;gap:9px;padding:7px 9px;font-size:12.5px;display:flex}.rail-link:hover{background:var(--graphite-hover);color:var(--graphite-bright)}.rail-link .dot{background:#3a3f49;border-radius:50%;flex:none;width:5px;height:5px}.meta{font-family:var(--mono);color:var(--muted);align-items:center;gap:12px;font-size:11px;display:flex}.tag{border:1px solid var(--rule);color:var(--ink-soft);border-radius:3px;padding:2px 7px}h1{font-family:var(--serif);letter-spacing:-.6px;margin:18px 0 16px;font-size:clamp(38px,5vw,54px);font-weight:400;line-height:1}h2{font-family:var(--sans);letter-spacing:-.3px;margin:40px 0 12px;font-size:20px;font-weight:600}.claim{color:var(--ink-soft);max-width:var(--measure);margin:0;font-size:18px;line-height:1.55}.claim+.claim{margin-top:14px}.rule{background:var(--rule);border:0;height:1px;margin:32px 0}.caption{font-family:var(--mono);color:var(--muted);margin-top:10px;font-size:11px}code,kbd{font-family:var(--mono);font-size:.92em}pre{font-family:var(--mono);background:var(--paper-raised);border:1px solid var(--rule);border-radius:6px;padding:14px 16px;font-size:13px;line-height:1.6;overflow-x:auto}.node-list{border-top:1px solid var(--rule);margin:24px 0 0;padding:0;list-style:none}.node-row{border-bottom:1px solid var(--rule);align-items:baseline;gap:14px;padding:13px 0;display:flex}.node-row .idx{font-family:var(--mono);color:var(--muted);flex:none;width:34px;font-size:10.5px}.node-row .title{color:var(--ink);font-size:16px}.node-row .wk{font-family:var(--mono);color:var(--muted);margin-left:auto;font-size:10.5px}.node-row a:hover .title{text-underline-offset:3px;text-decoration:underline}.node-row.locked .title{color:var(--muted)}@media (width<=900px){.app{flex-direction:column}.rail{flex-flow:wrap;align-items:center;gap:14px;width:100%;height:auto;position:static}.rail-nav,.rail-section,.rail-block{display:none}.main{padding:32px 20px 64px}}@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}.opt{text-align:left;border:1px solid var(--rule);background:var(--paper-raised);width:100%;max-width:660px;color:var(--ink-soft);font:inherit;cursor:pointer;border-radius:6px;align-items:baseline;gap:11px;margin-bottom:7px;padding:11px 14px;font-size:15px;display:flex}.opt:hover:not(:disabled){border-color:var(--rule-strong)}.opt:disabled{cursor:default}.opt .k{font-family:var(--mono);color:var(--muted);font-size:11px}.opt.correct{border-color:var(--signal);background:var(--signal-tint);color:var(--ink)}.opt.wrong{border-color:var(--warn);background:var(--warn-tint);color:var(--ink)}.btn{font:inherit;border:1px solid var(--ink);background:var(--ink);color:var(--paper);cursor:pointer;border-radius:6px;padding:9px 16px;font-size:14px}.btn:disabled{opacity:.45;cursor:not-allowed}.btn.ghost{color:var(--ink);border-color:var(--rule-strong);background:0 0;padding:7px 13px;font-size:13px}.btn.ghost:hover{border-color:var(--ink)}.node-row{align-items:flex-start}.node-row .idx{padding-top:3px}.row-body{flex:1;min-width:0}.row-claim{color:var(--muted);max-width:74ch;margin:4px 0 0;font-size:13.5px;line-height:1.45}.node-row.locked .row-claim{color:#a6aaa3}.rail-progress{border-top:1px solid var(--graphite-rule);font-family:var(--mono);color:var(--graphite-dim);margin-top:10px;padding-top:9px;font-size:10.5px}.rail-progress span{color:var(--signal)}