:root{color-scheme:dark;--bg:#191c19;--panel:#222620;--text:#eee7d8;--muted:#b9b9a8;--gold:#d4b77b;--line:#4b4d40}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.7 system-ui,sans-serif}a{color:inherit;text-decoration:none}button,input{font:inherit}button,a{touch-action:manipulation}button{cursor:pointer}button:disabled{cursor:default;opacity:.65}[hidden]{display:none!important}:focus-visible{outline:3px solid var(--gold);outline-offset:5px}.skip{position:absolute;top:-100px;background:var(--text);color:var(--bg);padding:12px;z-index:10}.skip:focus{top:0}header,main,footer{max-width:1240px;margin:auto}header{padding:24px 22px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);gap:15px}.brand{font:26px Georgia,serif;letter-spacing:-1px;white-space:nowrap}.seal{color:var(--gold);margin-right:8px}.brand-dot{color:var(--gold)}.nav-link{font-size:13px;color:var(--muted);padding:10px 0}main{padding:0 22px}.hero{padding:64px 0 32px;position:relative}.eyebrow{font-size:10px;letter-spacing:2.2px;font-weight:650;color:var(--gold)}h1,h2,h3{font-family:Georgia,'Times New Roman',serif;font-weight:400;line-height:1.15}h1{font-size:clamp(40px,7vw,82px);letter-spacing:-1.8px;margin:22px 0}h1 em{font-weight:400;color:var(--gold)}.hero p{color:var(--muted);font-size:17px;margin-bottom:28px}.primary{display:inline-flex;justify-content:space-between;align-items:center;gap:25px;background:var(--gold);color:#202219;border:1px solid var(--gold);padding:14px 18px;min-height:48px;font-size:14px;font-weight:650;max-width:100%;border-radius:3px}.primary:hover{background:#e5ce9b}.hero-note{font-size:11px;color:var(--muted);margin-top:16px}.ornament{display:flex;gap:0;justify-content:space-between;border-block:1px solid var(--line);margin-top:40px;padding:16px 12px;font:26px Georgia;color:#a5a88b}.section-heading{display:flex;justify-content:space-between;align-items:end;gap:15px;margin:32px 0 24px}.section-heading>.small{display:none}h2{font-size:32px;margin:10px 0}.small{font-size:12px;color:var(--muted)}.courses{display:grid;gap:14px}.course{display:flex;flex-direction:column;border:1px solid var(--line);padding:24px;background:linear-gradient(145deg,#262a22,#1e221e);border-radius:3px}.course.active{border-color:#9e8d64}.course.active:hover{background:#2c3026}.course-top{display:flex;justify-content:space-between;gap:8px;font-size:9px;letter-spacing:1px;color:var(--muted);align-items:center}.badge{border:1px solid #736e4f;color:#e1c68f;padding:3px 7px;border-radius:2px;font-size:10px;white-space:nowrap;letter-spacing:.3px}.glyph{font:32px Georgia;color:var(--gold);margin:30px 0 12px;letter-spacing:4px}.course h3{font-size:26px;margin:0 0 12px}.course p{font-size:13px;color:var(--muted);margin:0 0 24px}.course-foot{margin-top:auto;border-top:1px solid var(--line);padding-top:14px;font-size:10px;color:var(--muted);display:flex;justify-content:space-between;gap:10px}.course-foot span{color:var(--gold)}.study{border-top:1px solid var(--line);margin-top:60px;padding-top:40px;display:grid;gap:25px;scroll-margin-top:20px}.study aside>p{color:var(--muted);max-width:36ch}.method{display:flex;flex-direction:column;gap:8px;font-size:12px;color:var(--gold);margin:24px 0}.exercise{background:#e9e1cf;color:#292d25;border:1px solid #e9e1cf;border-radius:3px;padding:24px 20px}.exercise-top{display:flex;justify-content:space-between;align-items:center;font-size:11px;color:#505747}.exercise .badge{color:#5a4925;border-color:#918164}.exercise h3{font-size:30px;margin:22px 0 15px}.exercise p{font-size:14px}.exercise fieldset{padding:0;border:0;margin:25px 0}.exercise legend{font-family:Georgia,serif;font-size:21px;line-height:1.45;margin-bottom:18px}#options{display:grid;gap:10px;width:100%}.option{border:1px solid #b3af9c;border-radius:3px;display:flex;gap:12px;align-items:center;min-height:52px;padding:12px;font-size:14px;cursor:pointer}.option:has(input:checked){border-color:#475941;background:#d6dbc7}.option input{accent-color:#42533b;width:18px;height:18px;flex-shrink:0}.exercise .primary{background:#323f30;color:#fff4dc;border-color:#323f30;width:100%}.exercise .primary:hover{background:#42553f}.exercise .small{color:#545b4f}.disclosure{border-top:1px solid #b3af9c;padding-top:16px;margin-top:24px}#feedback{margin-top:20px;padding:16px;border-left:3px solid #6c7049;background:#d7d9c7;font-size:14px}#feedback strong{display:block;margin-bottom:5px}.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:15px}.secondary{min-height:48px;border:1px solid #6a725e;color:#2d3928;background:transparent;padding:10px 16px;border-radius:3px}.closing{text-align:center;padding:56px 0}.closing>span:first-child{color:var(--gold);font:34px Georgia}.closing p{font:28px Georgia;margin:15px 0 8px}footer{padding:24px 22px;border-top:1px solid var(--line);display:flex;gap:12px;flex-direction:column;font-size:12px;color:var(--muted)}footer>span:first-child{font:22px Georgia;color:var(--text)}@media(min-width:650px){.courses{grid-template-columns:1fr 1fr}.hero{padding-top:80px}.section-heading>.small{display:block}.exercise{padding:32px}header,footer{padding-inline:36px}main{padding-inline:36px}footer{flex-direction:row;justify-content:space-between;align-items:center}}@media(min-width:1050px){.courses{grid-template-columns:repeat(4,1fr)}.course{padding:22px}.course h3{font-size:25px}.study{grid-template-columns:1fr 1.55fr;gap:80px;padding-top:60px;margin-top:80px}.hero{padding-bottom:45px}.ornament{position:absolute;right:40px;top:75px;width:210px;height:210px;border:1px solid var(--line);border-radius:50%;display:grid;grid-template-columns:1fr 1fr;place-items:center;transform:rotate(-12deg);font-size:42px;opacity:.8}.ornament span:last-child{grid-column:1/3}.hero p{font-size:18px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
.path-banner{border-bottom:1px solid #a9ac97;padding-bottom:24px;margin-bottom:24px}.path-banner .eyebrow{color:#5d512f}.path-banner h3{margin-top:12px}.path-banner details{border-top:1px solid #b3af9c;padding:10px 0;font-size:14px}.path-banner summary{cursor:pointer;min-height:44px;display:list-item;align-content:center}.path-select{display:grid;gap:8px;font-size:12px;margin-top:16px}.path-select select{width:100%;max-width:100%;min-width:0;min-height:48px;padding:10px;background:#f4eddc;color:#292d25;border:1px solid #7e8572;border-radius:3px;font:14px system-ui}.path-banner progress{width:100%;height:8px;accent-color:#45583c;display:block;margin-top:18px}.reward{border:1px solid var(--line);padding:22px;margin-top:24px;border-radius:4px;background:#22271f}.reward strong{display:block;font:23px Georgia;margin-top:12px}.reward p,.reward li{font-size:12px;color:var(--muted)}.reward ul{list-style:none;padding:0;margin-bottom:0}.seal-art{border:3px double #938361;border-radius:50%;height:64px;width:64px;display:grid;place-items:center;font:32px Georgia;color:#c8af77}.reward.earned{border-color:var(--gold)}.earned .seal-art{color:#f4d292;border-color:var(--gold);background:#3a3727}.completion{border:1px solid var(--gold);padding:28px;margin-top:35px;background:var(--panel)}.completion p{max-width:65ch;color:var(--muted)}
/* Mobile: the active task precedes optional progress and collections. */
.study>.exercise{order:0;min-width:0}.study>aside{order:1;min-width:0}.trail{list-style:none;padding:0;display:grid;gap:8px;margin:22px 0}.trail button{width:100%;text-align:left;min-height:46px;border:1px solid var(--line);background:transparent;color:var(--muted);padding:10px 14px;border-radius:3px;font-size:12px}.trail button[aria-current]{border-color:var(--gold);color:var(--text);background:#30372a}.trail button:hover{background:#30372a}.milestone-collection{border-top:1px solid var(--line);padding-top:24px;margin-top:28px}.milestone-collection h3{font-size:26px;margin:12px 0}#milestone-gallery{display:grid;gap:9px}.milestone-card{display:flex;align-items:center;text-align:left;gap:14px;border:1px solid #8f805d;background:#252d22;color:var(--text);min-height:72px;width:100%;padding:12px;border-radius:4px}.milestone-card:disabled{opacity:1;border-color:var(--line);background:#20251f;color:#b1b3a5}.milestone-card>span:last-child{min-width:0}.milestone-card strong{display:block;font:17px Georgia}.milestone-card span span{display:block;font:11px/1.6 system-ui;color:var(--muted);margin-top:4px}.milestone-icon{height:40px;width:40px;border:1px solid #8f805d;border-radius:50%;flex-shrink:0;display:grid;place-items:center;color:var(--gold);font:25px Georgia}.milestone-card:disabled .milestone-icon{border-color:var(--line);color:#a5a88b}.celebration-setting{display:flex;align-items:center;gap:10px;min-height:48px;font-size:12px;margin-top:16px}.celebration-setting input{height:20px;width:20px;accent-color:var(--gold)}dialog#celebration{padding:0;width:min(560px,calc(100% - 24px));max-height:calc(100dvh - 28px);border:1px solid #ab9360;border-radius:8px;background:#20281f;color:var(--text);overflow:auto;box-shadow:0 24px 100px #0008}dialog::backdrop{background:#080d0bd9}.celebration-body{padding:24px}.celebration-art{margin:20px -8px 10px;overflow:hidden}.celebration-art svg{display:block;width:100%;height:auto}.celebration-body h2{font-size:32px;margin:10px 0 15px}.celebration-body>p:not(.small){font-size:15px;line-height:1.7;color:var(--muted)}.celebration-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:22px}.celebration-actions .secondary{color:var(--text);border-color:#a18a5a}.celebration-actions button{flex:1 1 auto}.scene-glow{animation:archive-glow 3s ease-out both}.scene-lamp{animation:archive-enter 1.4s ease-out both;transform-origin:center}.lamp-bulb{animation:archive-glow 2s ease-out both}.scene-doors .door-left{animation:archive-door-left 2s ease-in-out both;transform-origin:211px 150px}.scene-doors .door-right{animation:archive-door-right 2s ease-in-out both;transform-origin:429px 150px}.scene-reveal{animation:archive-enter 2.4s ease-out both}.scene-book{animation:archive-book 2s ease-out both;transform-origin:320px 230px}.book-ribbon{animation:archive-enter 2.5s ease-out both}.scene-seal{animation:archive-seal 2s cubic-bezier(.2,.7,.2,1) both;transform-origin:320px 160px}@keyframes archive-glow{from{opacity:0}to{opacity:1}}@keyframes archive-enter{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}@keyframes archive-door-left{from{transform:scaleX(1)}to{transform:scaleX(.18)}}@keyframes archive-door-right{from{transform:scaleX(1)}to{transform:scaleX(.18)}}@keyframes archive-book{from{opacity:0;transform:translateY(12px) scaleY(.35)}to{opacity:1;transform:translateY(0) scaleY(1)}}@keyframes archive-seal{from{opacity:0;transform:translateY(-24px) scale(.85)}to{opacity:1;transform:translateY(0) scale(1)}}@media(min-width:1050px){.study>.exercise{order:1}.study>aside{order:0}}@media(prefers-reduced-motion:reduce){.celebration-art *{animation:none!important}.scene-doors .door-left,.scene-doors .door-right{transform:scaleX(.18)}}
#path-label{display:block;margin-top:22px}.logic-lab{border:1px solid #858d76;border-radius:4px;padding:12px 16px;margin:0 0 24px}.logic-lab summary{cursor:pointer;min-height:48px;align-content:center;font-family:Georgia,serif;font-size:20px}.logic-lab input[type=text],#formula-input{width:100%;min-height:50px;border:1px solid #7e8572;border-radius:3px;background:#f4eddc;color:#292d25;padding:12px;font-size:20px;font-family:Georgia,serif;margin-top:8px}.symbol-pad{display:flex;gap:7px;flex-wrap:wrap;margin-top:12px}.symbol-pad button{min-height:48px;min-width:44px;padding:6px 12px;border:1px solid #858d76;background:#d7dbc9;color:#253023;border-radius:3px;font:23px Georgia}.symbol-pad button:hover{background:#c2cbb4}.logic-lab .primary{width:auto}.helper-toggle{display:flex;gap:10px;align-items:center;font-size:13px;margin-top:22px;min-height:48px}.helper-toggle input{height:20px;width:20px;flex-shrink:0;accent-color:#40523a}.table-scroll{overflow-x:auto;max-width:100%;margin:16px 0}.table-scroll table{border-collapse:collapse;width:100%;font-size:14px}.table-scroll caption{text-align:left;line-height:1.5;margin-bottom:10px}.table-scroll td,.table-scroll th{border:1px solid #8b937e;padding:10px;text-align:center;white-space:nowrap}.table-scroll th{background:#d8dccb;font-weight:600}.table-scroll select{min-width:65px;min-height:44px;border:1px solid #77826b;border-radius:3px;background:#f4eddc;color:#292d25;padding:6px;font-size:16px}.table-scroll select[aria-invalid=true]{border:2px solid #9b422b;background:#f4ddce}#table-feedback{border-left:3px solid #6c7049;padding-left:12px}#table-feedback:empty{display:none}
.proof-lab h4{font:24px/1.3 Georgia;margin:24px 0 12px}.proof-lines{list-style:none;padding:0;border-top:1px solid #8b937e;margin:20px 0}.proof-line{display:grid;grid-template-columns:24px minmax(0,1fr) auto;column-gap:8px;row-gap:6px;padding:12px 0;border-bottom:1px solid #a6ad98;align-items:start}.proof-number{font-size:12px;color:#5a6352}.proof-line-formula{font:19px/1.5 Georgia;overflow-wrap:anywhere}.proof-reason{font-size:11px;color:#48513f;max-width:110px;overflow-wrap:anywhere}.proof-line details{grid-column:2/4;font-size:12px}.proof-line details summary{font:12px/1.5 system-ui;min-height:36px}.proof-line details p{font-size:12px;margin:8px 0}.closed-proof-line{background:#d5d7c8}.closed-proof-line .proof-number:after{content:' ·';color:#715d3b}.proof-context,.proof-help{padding:12px;background:#d7dbc9;border-left:3px solid #6a7757;font-size:13px!important}.proof-refs{display:grid;grid-template-columns:1fr;gap:12px;margin:18px 0}.proof-refs label{display:grid;gap:6px;font-size:12px}.proof-refs select{width:100%;min-width:0;min-height:48px;padding:8px;background:#f4eddc;color:#292d25;border:1px solid #7e8572;border-radius:3px;font-size:14px}#proof-feedback{border-left:3px solid #6c7049;padding-left:12px}.proof-worked{font:14px/1.7 system-ui;padding:8px 12px;background:#d7dbc9;overflow-wrap:anywhere}.proof-worked ol{padding-left:20px}@media(min-width:650px){.proof-refs{grid-template-columns:repeat(2,minmax(0,1fr))}}
/* Fitch: a continuous root rail, one rail per assumption, and assumption dividers. */
.fitch-line{position:relative;border-bottom:0;min-height:56px}.fitch-root-rail,.fitch-scope-rail{position:absolute;top:0;bottom:0;border-left:1px solid #606a52;pointer-events:none}.fitch-root-rail{left:32px}.fitch-line details{padding-left:calc(12px + var(--proof-depth)*16px)}.fitch-line.fitch-assumption:after{content:'';position:absolute;bottom:0;left:calc(32px + var(--proof-depth)*16px);right:0;border-bottom:1px solid #606a52;pointer-events:none}.fitch-line.fitch-premise-end:after{content:'';position:absolute;bottom:0;left:32px;right:0;border-bottom:1px solid #606a52;pointer-events:none}.proof-lines{border-top:0}.closed-proof-line .proof-number:after{content:''}.fitch-line .proof-line-formula{min-width:0}