@charset "UTF-8";
:root{--paper:#f6f5ef;--card:#fffefa;--ink:#21352f;--muted:#6d7972;--green:#165a4c;--green-dark:#103d34;--mint:#e4efe6;--line:#dce2d8;--gold:#e6bd5e;--gold-light:#fbf1d5;--red:#b45343;--red-light:#fae9e1;--radius:16px;--rail:254px;font-family:Inter,"Segoe UI","Microsoft YaHei","PingFang SC",sans-serif;color:var(--ink);background:var(--paper);font-size:15px;line-height:1.7}
*{box-sizing:border-box}body{margin:0}button,input,select,textarea{font:inherit}button,a,input,select,textarea,summary{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.42}a{color:var(--green);text-decoration:none}a:hover{text-decoration:underline}button{border:0}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #b38926;outline-offset:3px}h1,h2,h3,p{margin-top:0}h1,h2,h3{line-height:1.35;letter-spacing:-.025em}p:last-child{margin-bottom:0}svg{max-width:100%}table{border-collapse:collapse}button.primary,.button{display:inline-flex;align-items:center;justify-content:center;gap:12px;padding:11px 20px;border-radius:9px;background:var(--green);color:white;font-weight:650;text-decoration:none;transition:background .15s,transform .15s}.button:hover,button.primary:hover{background:var(--green-dark);transform:translateY(-1px)}.button.secondary,button.secondary{background:white;color:var(--green);border:1px solid var(--line)}button.secondary{padding:9px 15px;border-radius:8px}.text-btn{background:none;color:var(--muted);font-size:13px;padding:5px 0}.text-btn:hover{color:var(--green)}.icon-btn{width:38px;height:38px;border-radius:8px;background:transparent;color:var(--ink)}.eyebrow{font-size:11px;font-weight:750;letter-spacing:.17em;color:var(--green);text-transform:uppercase}.chip{padding:4px 10px;font-size:12px;background:var(--mint);color:var(--green);border-radius:20px;white-space:nowrap}.muted{color:var(--muted)}.skip-link{position:fixed;z-index:100;top:-100px;left:20px;background:var(--card);padding:10px}.skip-link:focus{top:10px}
#sidebar{width:var(--rail);height:100dvh;position:fixed;inset:0 auto 0 0;background:#fdfcf7;border-right:1px solid var(--line);padding:28px 20px 18px;display:flex;flex-direction:column;z-index:30}.brand{display:flex;gap:12px;align-items:center;color:var(--ink);font-size:22px;font-weight:750;line-height:1.2}.brand:hover{text-decoration:none}.brand-mark{display:grid;place-items:center;width:45px;height:45px;background:var(--green-dark);color:#f1d484;border-radius:13px;font-family:Georgia,serif;font-size:32px}.brand-sub{display:block;font-size:12px;letter-spacing:.12em;font-weight:500;margin-top:5px}.rail-note{font-size:8px;color:#91a197;letter-spacing:.13em;margin:18px 0 21px}.search-wrap{display:flex;align-items:center;gap:7px;border:1px solid var(--line);border-radius:8px;background:#f1f3ed;padding:5px 9px}.search-wrap span{font-size:23px}.search-wrap input{background:transparent;border:0;min-width:0;width:100%;font-size:12px;outline:none;padding:4px 0}#search-status{font-size:11px;color:var(--muted);margin-top:4px;min-height:15px}#nav{overflow-y:auto;margin:0 -10px;flex:1;padding:2px 8px;scrollbar-width:thin;scrollbar-color:#d2dbd1 transparent}.nav-label{font-size:10px;color:var(--muted);font-weight:650;margin:21px 8px 8px;letter-spacing:.07em}.nav-link{display:flex;align-items:center;gap:9px;padding:8px;border-radius:7px;font-size:12px;color:#5a6c60;line-height:1.5}.nav-link:hover{background:#edf1e8;text-decoration:none}.nav-link.active{background:var(--green);color:white}.nav-num{font:11px ui-monospace,monospace;opacity:.65;min-width:20px}.nav-link .dot{width:5px;height:5px;background:var(--gold);border-radius:50%;margin-left:auto;flex-shrink:0}.rail-bottom{font-size:10px;color:var(--muted);padding:16px 5px 0;border-top:1px solid var(--line);margin-top:12px}.rail-bottom .text-btn{display:inline-block;font-size:10px;margin:8px 15px 0 0}.offline-dot{display:inline-block;background:#699b6c;border-radius:50%;width:5px;height:5px;margin-right:6px}.import-label{cursor:pointer}.page-shell{margin-left:var(--rail);min-width:0}.topbar{min-height:71px;padding:16px 4.5%;display:flex;align-items:center;gap:20px;border-bottom:1px solid var(--line);background:rgba(246,245,239,.94);position:sticky;top:0;z-index:20;backdrop-filter:blur(12px)}.crumb{font-size:12px;color:var(--muted)}.top-tag{font-size:11px;color:#859087;margin-left:auto}#focus-toggle{border-left:1px solid var(--line);padding-left:20px}#menu-toggle{display:none}#main{max-width:1510px;margin:auto;padding:40px 4.5% 55px;min-height:80vh}footer{border-top:1px solid var(--line);padding:21px 4.5%;font-size:11px;color:var(--muted);display:flex;justify-content:space-between;gap:12px}.focus-mode #sidebar{display:none}.focus-mode .page-shell{margin-left:0}.focus-mode #main{max-width:1130px}
.hero{display:grid;grid-template-columns:1.15fr 1fr;gap:32px;align-items:center;padding:26px 0 48px;border-bottom:1px solid var(--line)}.hero h1{font-family:"Noto Serif SC","STSong","SimSun",serif;font-size:clamp(36px,3.8vw,58px);font-weight:650;line-height:1.35;margin:22px 0;letter-spacing:.015em}.hero h1 em{font-style:normal;color:var(--green);position:relative}.hero h1 em:after{content:"";position:absolute;bottom:-7px;left:0;right:0;height:6px;background:var(--gold);border-radius:60% 20%;opacity:.65}.hero-desc{max-width:450px;font-size:14px;color:var(--muted);line-height:1.95}.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:27px}.hero-caption{display:flex;gap:20px;color:var(--muted);font-size:11px;margin-top:22px}.hero-art{background:var(--green-dark);border-radius:22px;color:white;position:relative;padding:26px;overflow:hidden;box-shadow:0 16px 40px #183f3612}.hero-art:after{content:"";width:240px;height:240px;border:1px solid #46715e;border-radius:50%;position:absolute;right:-115px;top:-120px;pointer-events:none}.art-head{display:flex;justify-content:space-between;align-items:center;font-size:10px;letter-spacing:.12em;color:#b6cebe}.art-label{font-size:12px;color:#b6cebe;margin:29px 0 14px}.hero-array{display:flex;gap:7px;margin:20px 0}.hero-array span{display:grid;place-items:center;min-width:0;flex:1;height:54px;border:1px solid #476456;border-radius:9px;color:#b6cebe;font:22px Georgia,serif;position:relative}.hero-array .picked{color:#18392b;background:#e8c96f;border-color:#e8c96f}.hero-array span small{position:absolute;bottom:-23px;font:10px sans-serif;color:#91ac98}.art-result{display:flex;justify-content:space-between;margin:44px 0 21px;padding-bottom:19px;border-bottom:1px solid #3c5b4d;align-items:end}.art-result strong{font:40px Georgia,serif;color:#f3d481}.art-result span{font-size:12px;color:#c4d4c7}.art-proof{font-size:12px;line-height:1.9;color:#d6e2d9}.art-proof b{color:#f3d481}.section-title{display:flex;align-items:end;justify-content:space-between;gap:16px;margin:36px 0 18px}.section-title h2{font-size:22px;margin:0}.section-title p{font-size:12px;color:var(--muted);margin:0}.learning-loop{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;padding:29px 0 5px}.loop-item{border-top:2px solid #cad8c9;padding-top:13px}.loop-item span{font:12px ui-monospace,monospace;color:#7c9783}.loop-item h3{font-size:15px;margin:8px 0}.loop-item p{font-size:12px;color:var(--muted);line-height:1.8}.course-group{margin:20px 0 25px}.group-title{font-size:11px;letter-spacing:.1em;color:var(--muted);margin:24px 0 10px}.course-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.course-card{display:flex;flex-direction:column;min-height:177px;padding:19px;border:1px solid var(--line);border-radius:12px;background:var(--card);color:var(--ink);position:relative;transition:border-color .15s,transform .15s}.course-card:hover{border-color:#9db7a3;transform:translateY(-3px);text-decoration:none}.card-top{display:flex;justify-content:space-between;align-items:center;font-size:10px;color:var(--muted)}.card-num{font:22px Georgia,serif;color:#86a08c}.course-card h3{font-size:16px;margin:16px 0 8px}.course-card p{font-size:11px;color:var(--muted);margin:0}.card-arrow{margin-left:auto;margin-top:14px;font-size:17px;color:var(--green)}.route-tip{background:var(--gold-light);border-left:3px solid var(--gold);padding:17px 21px;border-radius:4px 12px 12px 4px;font-size:12px;color:#715a2c}.route-tip a{font-weight:650}.doc-links{display:flex;flex-wrap:wrap;gap:10px}.doc-links a{padding:10px 15px;border:1px solid var(--line);border-radius:8px;background:var(--card);font-size:12px}
.lesson-heading{margin:2px 0 25px}.lesson-meta{display:flex;gap:12px;align-items:center;margin-bottom:15px}.lesson-meta .num{font:17px Georgia,serif;color:#92a698}.lesson-heading h1{font-size:clamp(28px,3vw,40px);margin:0 0 12px}.lesson-heading p{font-size:14px;color:var(--muted)}.prereq{font-size:11px;color:var(--muted);margin-top:13px}.lesson-tabs{display:flex;gap:25px;border-bottom:1px solid var(--line);margin:0 0 28px}.lesson-tabs button{background:transparent;padding:10px 0 13px;color:var(--muted);font-size:13px;position:relative}.lesson-tabs button[aria-selected=true]{color:var(--green);font-weight:750}.lesson-tabs button[aria-selected=true]:after{content:"";height:3px;background:var(--green);position:absolute;left:0;right:0;bottom:-1px}.concept-panel{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:27px 28px;margin-bottom:25px}.concept-panel h2{font-size:19px;margin:8px 0 16px}.formula-box{overflow-x:auto;padding:16px 15px;border-radius:9px;background:#f0f4ed;margin:19px 0}.formula-box .katex-display{margin:0;font-size:1.1em}.conditions{font-size:12px;color:var(--muted);line-height:1.8}.symbols{display:grid;grid-template-columns:repeat(2,1fr);gap:10px;margin-top:20px}.symbol{font-size:12px;padding:10px 0;border-top:1px solid var(--line)}.symbol b{display:block;color:var(--green);margin-bottom:3px}.proof-cue{display:grid;grid-template-columns:1fr 1fr;gap:17px;margin:19px 0 0}.cue{font-size:12px;line-height:1.85;border-radius:9px;padding:16px;background:var(--mint)}.cue.warning{background:var(--gold-light)}.cue strong{display:block;font-size:11px;margin-bottom:6px}.read-layout{display:grid;grid-template-columns:minmax(0,1fr) 170px;gap:30px;align-items:start}.reading{background:var(--card);border:1px solid var(--line);padding:30px clamp(20px,3vw,44px);border-radius:var(--radius);min-width:0;font-size:15px;line-height:1.95}.reading h2{font-size:23px;border-top:1px solid var(--line);padding-top:30px;margin:36px 0 20px;scroll-margin-top:95px}.reading h2:first-child{margin-top:0;border-top:0;padding-top:0}.reading h3{font-size:18px;margin:30px 0 15px;scroll-margin-top:95px}.reading p{margin-bottom:18px}.reading ul,.reading ol{padding-left:25px}.reading li{margin-bottom:6px}.reading blockquote{margin:20px 0;padding:15px 20px;border-left:3px solid var(--green);background:#eff4ed;border-radius:0 8px 8px 0}.reading code{background:#eef1ea;color:#295b4b;border-radius:4px;padding:2px 5px;font:12px/1.7 "Cascadia Code",Consolas,monospace;word-break:break-word}.reading pre{background:#142d28;padding:20px;border-radius:10px;overflow-x:auto;line-height:1.8}.reading pre code{color:#e2ece2;background:none;padding:0;font-size:12px;white-space:pre;word-break:normal}.reading table{font-size:12px;line-height:1.7;width:100%;min-width:320px}.reading th,.reading td{padding:10px 12px;border:1px solid var(--line);vertical-align:top}.reading th{background:#ecf1e7;font-weight:650}.reading tr:nth-child(even) td{background:#fafbf6}.table-scroll{overflow-x:auto;margin:20px 0}.reading hr{border:0;border-top:1px solid var(--line);margin:35px 0}.reading a{text-decoration:underline;text-underline-offset:3px}.reading details{background:#f3f5ed;border:1px solid var(--line);border-radius:10px;padding:16px 19px;margin:28px 0}.reading details summary{cursor:pointer;font-size:14px;font-weight:650;color:var(--green)}.reading details[open] summary{margin-bottom:20px}.reading details h2{font-size:19px}.toc{position:sticky;top:102px;font-size:11px;border-left:1px solid var(--line);padding-left:17px;max-height:74vh;overflow:auto;scrollbar-width:thin}.toc b{display:block;margin-bottom:15px}.toc a{display:block;color:var(--muted);line-height:1.8;margin:12px 0}.toc a:hover{color:var(--green)}.source-row{font-size:11px;color:var(--muted);margin:17px 0 25px;display:flex;flex-wrap:wrap;gap:18px}.lesson-bottom{margin:30px 0 0;display:flex;justify-content:space-between;gap:15px}.lesson-bottom a{font-size:12px;padding:10px 0}.doc-heading{font-size:32px;margin-bottom:25px}
.lab-intro{display:flex;gap:20px;align-items:start;justify-content:space-between;margin-bottom:20px}.lab-intro h2{font-size:22px;margin:0 0 8px}.lab-intro p{font-size:13px;color:var(--muted)}.lab-legend{display:flex;gap:14px;font-size:10px;color:var(--muted);margin:10px 0 20px;flex-wrap:wrap}.lab-legend i{display:inline-block;width:8px;height:8px;border-radius:3px;margin-right:4px}.lab-legend .active{background:var(--gold)}.lab-legend .selected{background:var(--green)}.lab-legend .rejected{background:#c58772}.experiment{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden}.lab-config{padding:16px 22px;border-bottom:1px solid var(--line);display:flex;align-items:center;gap:12px;flex-wrap:wrap;background:#fcfcf5;font-size:12px}.lab-config select{border:1px solid #cad6c8;background:white;border-radius:7px;padding:6px 10px;font-size:12px;max-width:100%}.lab-config .case-label{color:var(--muted)}.lab-stage{display:grid;grid-template-columns:minmax(0,1fr) 270px;min-height:370px}.scene-col{padding:23px;min-width:0}.frame-heading{display:flex;justify-content:space-between;align-items:center;font-size:12px;color:var(--muted);margin-bottom:22px}.frame-heading strong{color:var(--green);font-size:15px}.scene{min-height:225px;overflow:auto;padding:7px 0}.scene h3,.scene h4{font-size:13px;margin:12px 0}.scene p{font-size:12px;color:var(--muted);margin:10px 0}.scene>div{max-width:100%}.scene:focus{outline:none}.metrics{display:flex;gap:10px;flex-wrap:wrap;margin:20px 0 0}.metric{border:1px solid var(--line);background:#f6f8f1;border-radius:7px;padding:7px 12px;min-width:80px;font-size:10px;color:var(--muted)}.metric b{display:block;font-size:15px;font-family:"Cascadia Code",monospace;color:var(--green);max-width:350px;overflow-wrap:anywhere}.code-col{background:#173a31;padding:22px 0;color:#d9e8de;min-width:0}.code-label{font-size:10px;letter-spacing:.14em;color:#98bba6;margin:0 18px 20px}.lab-code{margin:0;padding:0 12px;list-style:none;font:11px/1.85 "Cascadia Code",Consolas,monospace;white-space:pre-wrap;overflow-wrap:anywhere}.lab-code li{padding:7px 8px 7px 31px;position:relative;border-radius:5px;border-left:2px solid transparent}.lab-code li:before{content:attr(data-line);position:absolute;left:7px;color:#6d9380;font-size:10px}.lab-code li.current{color:#f8e7a3;background:#315442;border-left-color:var(--gold)}.lab-controls{padding:17px 22px;border-top:1px solid var(--line);display:flex;align-items:center;gap:8px;flex-wrap:wrap}.lab-controls button{font-size:12px;padding:8px 13px;border-radius:7px;background:#eaf0e4;color:var(--green)}.lab-controls .play{background:var(--green);color:white;min-width:76px}.lab-controls .range{width:100%;accent-color:var(--green);margin:4px 0 9px}.speed-label{margin-left:auto;font-size:11px;color:var(--muted)}.speed-label select{font-size:11px;padding:5px;border:1px solid var(--line);border-radius:5px;background:white}.frame-count{font-size:11px;color:var(--muted);margin-left:7px;font-variant-numeric:tabular-nums}.explanation{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:17px 0}.explanation>div{border:1px solid var(--line);padding:18px;border-radius:10px;background:var(--card);font-size:13px;line-height:1.85}.explanation h3{font-size:11px;color:var(--muted);margin-bottom:9px;letter-spacing:.08em}.explanation .invariant{background:var(--mint);border-color:#d4e1d0}.prediction{border:1px solid #e1c47c;background:var(--gold-light);border-radius:12px;padding:21px;margin:17px 0}.prediction h3{font-size:15px;margin:5px 0 14px}.prediction .options{display:grid;gap:8px}.option{display:block;text-align:left;background:#fffdf5;color:var(--ink);border:1px solid #e5d8b8;border-radius:7px;padding:10px 13px;font-size:12px}.option.chosen{border-color:#a58338;background:#f6e3ae}.option.correct{border-color:#518268;background:#e1efdf}.feedback{margin-top:12px;font-size:12px;color:#69542c}.array-viz{display:flex;gap:7px;justify-content:center;flex-wrap:wrap;padding:15px 4px 25px}.array-cell{min-width:42px;max-width:92px;border:1px solid #cdd9ca;position:relative;border-radius:8px;text-align:center;background:#f2f5ed;color:var(--green);padding:11px 9px;font:18px "Cascadia Code",monospace;transition:background .25s,transform .25s}.array-cell.active{background:var(--gold);border-color:var(--gold);transform:translateY(-4px);color:#3c351b}.array-cell.selected{background:var(--green);border-color:var(--green);color:white}.array-cell.rejected{background:#f2e5df;color:#986f60;border-style:dashed;opacity:.75}.array-cell small{position:absolute;font:9px sans-serif;left:0;right:0;bottom:-20px;color:var(--muted);white-space:nowrap}.viz-table{overflow:auto;max-width:100%;padding:5px}.viz-table table{min-width:100%;font:12px/1.6 "Cascadia Code",Consolas,monospace}.viz-table th,.viz-table td{border:1px solid #d6dfd0;text-align:center;min-width:34px;padding:8px 7px;transition:background .2s}.viz-table th{background:#eaf0e3;color:#56715a}.viz-table td.active{background:var(--gold);font-weight:bold;color:#3b351a}.viz-table td.selected{background:var(--mint);color:var(--green);box-shadow:inset 0 0 0 1px #73a180}.graph-viz{width:100%;height:auto;min-height:220px;max-height:330px;overflow:visible}.graph-viz text{font-family:"Segoe UI","Microsoft YaHei",sans-serif}.graph-viz .edge{stroke:#b8cabb;stroke-width:2.3;fill:none;transition:stroke .2s}.graph-viz .edge.active{stroke:#bd9029;stroke-width:4}.graph-viz .edge.selected{stroke:var(--green);stroke-width:3.4}.graph-viz .edge.rejected{stroke:#ba806d;stroke-dasharray:6 5}.graph-viz .node{fill:#f3f6ec;stroke:#a4b8a3;stroke-width:2}.graph-viz .node.active{fill:var(--gold);stroke:#b18c3a}.graph-viz .node.selected{fill:var(--green);stroke:var(--green)}.graph-viz .node.rejected{fill:#f2e4dd;stroke:#ba806d}.graph-viz .node-text{fill:var(--green);font-size:18px;font-weight:700}.graph-viz .node-text.selected{fill:white}.graph-viz .edge-label{fill:#5c7260;font-size:13px;paint-order:stroke;stroke:#fffefa;stroke-width:5px;stroke-linejoin:round}.graph-viz .tag{fill:#5e7561;font-size:12px}.scene.changed{animation:scene-in .22s ease-out}@keyframes scene-in{from{opacity:.55;transform:translateY(3px)}to{opacity:1;transform:none}}
.practice-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px}.practice-card,.journal-card{padding:25px;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);margin-bottom:20px}.practice-card h2,.journal-card h2{font-size:20px}.practice-card p{font-size:13px}.practice-card details{margin:17px 0;padding:13px;background:#eff3e9;border-radius:8px;font-size:12px}.practice-card summary{cursor:pointer;color:var(--green);font-weight:650}.practice-card details p{margin-top:12px;font-size:12px}.field{display:block;margin:15px 0;font-size:12px;color:var(--muted)}.field input,.field textarea,.field select{display:block;width:100%;margin-top:7px;border:1px solid #ccd7c8;border-radius:8px;padding:10px 12px;background:white;color:var(--ink);font-size:13px}.field textarea{resize:vertical;min-height:120px;line-height:1.8}.checkline{display:flex;gap:9px;align-items:start;font-size:12px;line-height:1.9;margin:12px 0}.checkline input{accent-color:var(--green);margin-top:5px}.record{border-top:1px solid var(--line);padding:13px 0;font-size:12px}.record strong{color:var(--green)}.record p{white-space:pre-wrap;margin:7px 0}.record .date{font-size:10px;color:var(--muted)}.status-banner{padding:15px 18px;background:var(--mint);border-radius:9px;font-size:12px;margin:20px 0}.quiet-note{font-size:11px;color:var(--muted);line-height:1.9}.toast{position:fixed;left:50%;bottom:28px;transform:translateX(-50%);background:#173c31;color:white;border-radius:10px;padding:12px 22px;font-size:13px;box-shadow:0 8px 35px #123a3422;z-index:100;max-width:90vw}.empty{padding:30px;color:var(--muted);font-size:13px}.mobile-mask{display:none}
@media(min-width:1550px){:root{--rail:280px}.course-grid{grid-template-columns:repeat(4,minmax(0,1fr))}.lab-stage{grid-template-columns:minmax(0,1fr) 310px}}
@media(max-width:1180px){:root{--rail:225px}.read-layout{grid-template-columns:minmax(0,1fr)}.toc{display:none}.hero{gap:24px}.hero-art{padding:21px}.hero h1{font-size:37px}.lab-stage{grid-template-columns:minmax(0,1fr) 235px}.scene-col{padding:17px}.course-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.top-tag{display:none}.topbar #focus-toggle{margin-left:auto}.proof-cue{gap:10px}}
@media(max-width:850px){:root{--rail:250px}#sidebar{transform:translateX(-100%);transition:transform .2s}.nav-open #sidebar{transform:translateX(0);box-shadow:20px 0 60px #173c3133}.page-shell{margin-left:0}#menu-toggle{display:block}.topbar{padding:12px 5%;min-height:62px}.hero{grid-template-columns:1fr 1fr}.hero h1{font-size:36px}#main{padding:27px 5% 40px}.hero-caption{flex-wrap:wrap;gap:5px 14px}.lab-stage{grid-template-columns:minmax(0,1fr) 230px}.focus-mode #sidebar{display:flex}.focus-mode #main{max-width:100%}}
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