:root{color-scheme:light;--ink:#1a1a18;--muted:#686860;--line:#deded8;--wash:#f7f7f3;--accent:#a34d27;--serif:"Songti SC","Noto Serif CJK SC",STSong,SimSun,Georgia,serif;--sans:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:90px}body{margin:0;background:#fff;color:var(--ink);font:16px/1.8 var(--sans);-webkit-font-smoothing:antialiased}button,input,textarea,select{font:inherit;color:inherit;border-radius:0}button{cursor:pointer}button:disabled{cursor:default;opacity:.45}button:hover:not(:disabled){opacity:.75}a{color:inherit;text-decoration:none}a:hover{text-decoration:underline;text-underline-offset:4px}a,button,input,select,textarea,summary{-webkit-tap-highlight-color:transparent}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:2px solid var(--accent);outline-offset:4px}h1,h2,h3,p{margin-top:0}h1,h2,h3{font-family:var(--serif)}h2{font-size:clamp(27px,4vw,38px);line-height:1.35;margin-bottom:0}h3{font-size:23px;line-height:1.5}p{margin-bottom:16px}[hidden]{display:none!important}.wrap{width:min(1040px,calc(100% - 64px));margin-inline:auto}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.skip{position:absolute;left:16px;top:-100px;z-index:100;background:var(--ink);color:#fff;padding:10px}.skip:focus{top:10px}.mast{padding:19px 0 22px}.dateline{display:flex;justify-content:space-between;gap:20px;font-size:10px;letter-spacing:1px;color:var(--muted);margin-bottom:12px}.brand{font:700 32px/1.4 var(--serif);letter-spacing:.02em}.mast-note{float:right;font:16px/1.6 var(--serif);margin-top:8px;color:var(--muted)}.navbar{position:sticky;top:0;background:#fffffff7;backdrop-filter:blur(8px);border-block:1px solid var(--line);z-index:10}.nav-inner{display:flex;justify-content:space-between;align-items:center;gap:20px;min-height:64px}.nav-links{display:flex;gap:25px;align-items:center;white-space:nowrap;min-width:0}.nav-links a{font-size:13px;padding-block:18px}.nav-links a[aria-current]{color:var(--accent)}#saved-count{font-size:10px;padding-left:4px}.button{display:inline-flex;align-items:center;justify-content:center;background:var(--ink);color:#fff;border:1px solid var(--ink);padding:12px 22px;font-size:13px;font-weight:600;text-decoration:none;line-height:1.7}.button:hover{text-decoration:none;background:#373732}.button.compact{font-size:11px;padding:8px 12px;white-space:nowrap}.hero{padding:65px 0 50px}.eyebrow{font:10px/1.7 var(--sans);color:var(--muted);letter-spacing:1.5px;text-transform:uppercase;margin-bottom:10px}.hero h1{font-size:clamp(48px,7.8vw,84px);line-height:1.27;letter-spacing:-.035em;margin:24px 0 40px}.hero-foot{border-top:1px solid var(--ink);padding-top:26px;display:grid;grid-template-columns:minmax(0,1fr) 180px;gap:70px}.lede{font-size:15px;line-height:2.1;color:#4e4e48;margin-bottom:25px}.actions{display:flex;align-items:center;gap:22px;flex-wrap:wrap}.text-link,.text-button{font-size:13px}.text-button{background:none;border:0;padding:4px 0;line-height:1.8}.text-button:hover{text-decoration:underline;text-underline-offset:4px}.proof{border-left:1px solid var(--line);padding-left:25px}.proof strong{display:block;font:italic 50px/1.2 Georgia,serif;font-variant-numeric:tabular-nums}.proof>span{display:block;font-size:12px;color:var(--muted);margin-top:5px}.proof p{font:16px/1.9 var(--serif);margin:18px 0 0}.section{padding:35px 0 46px;border-top:1px solid var(--line);scroll-margin-top:20px}.section-head{display:flex;justify-content:space-between;align-items:flex-end;gap:24px;margin-bottom:23px}.section-head .eyebrow{margin-bottom:7px}.section-head>.text-link,.section-head>.text-button{flex-shrink:0}.section-lede{font-size:14px;color:var(--muted);margin-bottom:21px;max-width:850px}.small{font-size:12px}.muted{color:var(--muted)}.question-links{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));margin:0 0 21px;gap:30px}.question-links a{display:block;border-top:1px solid var(--ink);padding-top:13px;font:700 21px/1.65 var(--serif);position:relative;padding-right:21px}.question-links span{display:block;font:11px/1.8 var(--sans);color:var(--muted);margin-bottom:9px}.question-links b{position:absolute;right:0;bottom:0;color:var(--accent);font:18px/1.8 var(--sans)}.model-list,.rows{padding:0;list-style:none;margin:0}.model-row{border-top:1px solid var(--line)}.model-row:last-child{border-bottom:1px solid var(--line)}.model-row>a{display:grid;grid-template-columns:38px minmax(200px,.9fr) minmax(0,1.3fr) 25px;gap:16px;align-items:center;padding:19px 0;text-decoration:none}.model-row>a:hover h3{text-decoration:underline;text-underline-offset:4px}.row-number{font:italic 20px/1.5 Georgia,serif;color:#92928b;font-variant-numeric:tabular-nums}.model-row h3{font-size:22px;margin:0}.model-row .discipline{font-size:11px;color:var(--muted)}.model-row .question{font-size:14px;color:#55554f;margin:0}.arrow{font-size:19px;color:var(--accent)}.session{border-top:1px solid var(--line)}.session:last-child{border-bottom:1px solid var(--line)}.session summary{display:flex;gap:18px;align-items:baseline;cursor:pointer;list-style:none;padding:20px 0;font:700 23px/1.5 var(--serif)}.session summary::-webkit-details-marker{display:none}.session summary::after{content:"+";font:20px/1.5 var(--sans);margin-left:auto;color:var(--muted)}.session[open] summary::after{content:"−"}.session-body{margin:0 40px 24px 55px;max-width:830px;font-size:14px}.session-body h3{font:600 13px/1.7 var(--sans);margin:20px 0 9px}.session-body ol,.session-body ul{padding-left:1.4em}.session-body li{margin-bottom:8px}.session-body .goal{font-size:16px;color:#393936}.model-tags{display:flex;gap:7px 12px;flex-wrap:wrap;margin:12px 0 18px}.model-tags a{font-size:12px;color:var(--accent);border-bottom:1px solid #e1cbbc}.resources{padding-top:25px;font-size:13px}.resources h3{font-size:23px}.resources ul{padding-left:20px}.resources li{margin-bottom:12px}.resources a{text-decoration:underline;text-underline-offset:3px}.toolbar{border-top:1px solid var(--ink);padding-top:20px}.search{display:flex;align-items:center;gap:13px;border:1px solid #aaa99f;padding:10px 14px;margin-bottom:17px}.search>span{font-size:25px;line-height:1}.search input{flex:1;min-width:0;border:0;outline:none;background:none;font-size:14px;padding:4px 0}.search kbd{font:12px var(--sans);border:1px solid var(--line);padding:2px 6px;color:var(--muted)}.filter-row{display:flex;align-items:center;gap:12px 22px;flex-wrap:wrap;border-bottom:1px solid var(--line);padding-bottom:18px;margin-bottom:17px;font-size:12px}.filter-row label{display:flex;align-items:center;gap:7px;min-width:0}.filter-row select{border:0;border-bottom:1px solid #bbb;background:#fff;padding:3px 2px;max-width:160px;font-size:12px}.check-label input{accent-color:var(--ink)}.filter-row .text-button{font-size:12px;margin-left:auto}.resource{display:grid;grid-template-columns:36px minmax(0,1fr) auto;gap:16px;padding:25px 0;border-bottom:1px solid var(--line);align-items:start}.resource:first-child{border-top:1px solid var(--line)}.resource h3{font-size:23px;line-height:1.5;margin:0 0 5px;overflow-wrap:anywhere}.english-title{font-size:12px;line-height:1.8;color:#808077;margin-bottom:8px;overflow-wrap:anywhere}.row-summary{font-size:14px;line-height:1.9;color:#53534c;margin-bottom:11px}.row-meta{display:flex;gap:6px 13px;flex-wrap:wrap;font-size:11px;color:var(--muted)}.curated{color:var(--accent)}.save-button{border:1px solid var(--line);background:#fff;font-size:11px;white-space:nowrap;padding:5px 9px;line-height:1.6;margin-top:5px}.save-button[aria-pressed=true]{border-color:var(--accent);color:var(--accent);background:#faf7f3}.load-more{display:block;background:#fff;border:1px solid #aaa;width:100%;margin-top:20px;padding:12px;font-size:13px}.empty,.loading{padding:22px 0;color:var(--muted);font-size:14px}.empty p{margin-bottom:5px}.calc-inputs{display:grid;grid-template-columns:1fr 1fr 1fr auto;gap:20px;align-items:end}.calc-inputs label{display:flex;flex-direction:column;font-size:12px;gap:8px;min-width:0}.calc-inputs input{border:1px solid #bdbdb3;background:#fff;padding:10px 12px;min-width:0;width:100%;font-size:16px}.calc-inputs .button{height:50px}.calc-result{display:grid;grid-template-columns:1fr 1.1fr;gap:40px;align-items:center;padding:25px 0 18px}.calc-total{font:italic 40px/1.3 Georgia,serif;font-variant-numeric:tabular-nums;display:block;margin:3px 0 9px;overflow-wrap:anywhere}.calc-result p{font-size:13px;margin-bottom:8px}.calc-result svg{display:block;width:100%;height:auto;max-height:160px}.formula{font:14px/2.2 Georgia,var(--serif);border-top:1px solid var(--line);padding-top:16px}#notes{width:100%;padding:17px 19px;border:1px solid #bdbdb3;background:var(--wash);font-size:14px;line-height:1.9;resize:vertical;min-height:200px;display:block}#notes-status{margin-top:9px}.notebook-head{margin-top:30px;margin-bottom:10px}.notebook-head h3{margin:0}.method{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:35px}.method>div>span{font:italic 23px/1.5 Georgia,serif;color:#999990}.method h3{font-size:22px;margin:10px 0}.method p{font-size:13px;line-height:1.9;color:var(--muted);margin-bottom:0}.provenance{font-size:12px;color:var(--muted);margin:24px 0 16px}.provenance p{margin-bottom:10px}.provenance summary{cursor:pointer}.provenance pre{white-space:pre-wrap;overflow-wrap:anywhere;background:var(--wash);padding:15px;max-height:330px;overflow-y:auto;font:11px/1.8 monospace}.footer{border-top:1px solid var(--ink);padding:27px 0 32px;color:var(--muted);font-size:11px}.footer p{margin-bottom:7px}.footer strong{font:700 17px/1.7 var(--serif);color:var(--ink)}.footer a{text-decoration:underline;text-underline-offset:3px}.notice{background:var(--wash);border:1px solid var(--line);padding:13px 17px;font-size:13px;margin-top:20px}.notice button{margin-left:12px}.detail{padding:35px 0 70px;max-width:860px}.detail-back{font-size:13px;display:inline-block;margin-bottom:30px}.detail h1{font-size:clamp(32px,5vw,48px);line-height:1.45;margin-bottom:15px;overflow-wrap:anywhere}.detail .eyebrow{color:var(--accent)}.detail .english-title{font-size:16px;margin-bottom:20px}.detail .row-meta{margin-bottom:21px;font-size:12px}.detail .actions{padding:20px 0;border-block:1px solid var(--line)}.detail .save-button{font-size:13px;padding:10px 14px;margin:0}.detail-section{padding-top:31px}.detail-section h2{font-size:25px;margin-bottom:15px}.detail-section p{font-size:15px;line-height:2}.detail-section ul,.detail-section ol{font-size:15px;line-height:1.9;padding-left:23px}.detail-section li{margin-bottom:9px}.anchor-note{font-size:12px!important;color:var(--muted);border-left:2px solid #c4c4b9;padding-left:16px}.source-line{font-size:12px!important;color:var(--muted);overflow-wrap:anywhere}.source-line a,.rich a{text-decoration:underline;text-underline-offset:3px}.comment{padding:20px 0;border-top:1px solid var(--line)}.comment-meta{font-size:12px;color:var(--muted);display:flex;justify-content:space-between;gap:15px}.comment-meta a{text-decoration:underline;text-underline-offset:3px}.comment blockquote{margin:14px 0;padding-left:19px;border-left:2px solid #c6c6ba;font-size:14px;line-height:1.9;white-space:pre-line;overflow-wrap:anywhere}.comment .original{font-size:12px;color:var(--muted)}.comment summary{font-size:12px;cursor:pointer;color:var(--muted)}.comment .small{font-size:12px}.detail-section .rows .resource h3{font-size:21px}.rich{overflow-wrap:anywhere}.rich p:last-child{margin-bottom:0}.rich dl{margin:0}.rich dt{font-weight:600;font-size:13px;margin-top:12px}.rich dd{margin:2px 0 12px}.detail .notice{margin-top:0}.detail-question{font:22px/1.7 var(--serif)!important;color:#55554a}.answer{background:var(--wash);padding:18px 22px;margin-top:15px}.answer summary{font-size:13px;cursor:pointer}.answer .rich{margin-top:12px}.detail-footer{margin-top:40px;border-top:1px solid var(--line);padding-top:20px;display:flex;justify-content:space-between;gap:20px;font-size:13px}
@media(max-width:800px){.wrap{width:calc(100% - 40px)}.nav-links{gap:18px;overflow-x:auto;scrollbar-width:none}.nav-links::-webkit-scrollbar{display:none}.nav-inner{gap:13px}.hero{padding-top:44px}.hero-foot{gap:35px;grid-template-columns:minmax(0,1fr) 155px}.hero h1{font-size:65px}.question-links{gap:21px}.question-links a{font-size:19px}.model-row>a{grid-template-columns:30px minmax(160px,.8fr) minmax(0,1.2fr) 20px;gap:12px}.model-row h3{font-size:21px}.model-row .question{font-size:13px}.method{gap:24px}.calc-inputs{gap:12px}.calc-inputs .button{padding-inline:16px}}
@media(max-width:580px){html{scroll-padding-top:80px}.wrap{width:calc(100% - 32px)}.mast{padding:16px 0}.dateline{font-size:9px;letter-spacing:.3px;gap:10px}.dateline span:last-child{text-align:right;max-width:130px}.brand{font-size:26px}.mast-note{font-size:12px;margin-top:7px}.nav-inner{min-height:51px}.nav-links{gap:23px}.nav-links a{font-size:12px;padding-block:14px}.navbar .button{display:none}.hero{padding:35px 0}.hero h1{font-size:clamp(43px,10.5vw,60px);margin:20px 0 28px;line-height:1.3}.hero-foot{display:block;padding-top:21px}.lede{font-size:14px;line-height:2}.actions{gap:18px}.button{font-size:12px;padding:11px 16px}.text-link,.text-button{font-size:12px}.proof{display:flex;flex-wrap:wrap;align-items:baseline;gap:7px 13px;padding:18px 0 0;margin-top:26px;border-left:0;border-top:1px solid var(--line)}.proof strong{font-size:36px}.proof p{margin:0;flex-basis:100%;font-size:14px}.section{padding:27px 0 33px}.section-head{gap:12px;margin-bottom:20px;align-items:flex-start}.section-head>.text-link,.section-head>.text-button{max-width:105px;text-align:right;font-size:11px;padding-top:24px}.section-head>.small{padding-top:25px;max-width:130px;text-align:right;font-size:10px}.section-lede{font-size:13px}.question-links{grid-template-columns:1fr;gap:0;margin-bottom:16px}.question-links a{padding:15px 23px 15px 0;font-size:21px;border-top:1px solid var(--line)}.question-links span{margin:0 0 4px;font-size:10px}.question-links b{bottom:17px}.model-row>a{grid-template-columns:25px minmax(0,1fr) 20px;gap:5px 10px;padding:17px 0}.model-row .question{grid-column:2;grid-row:2;font-size:13px}.model-row .arrow{grid-column:3;grid-row:1/3}.model-row .row-number{grid-row:1/3;align-self:start;padding-top:4px;font-size:17px}.model-row h3{font-size:21px}.model-row .discipline{font-size:10px}.session summary{font-size:21px;gap:13px;padding:17px 0}.session summary .row-number{font-size:17px}.session-body{margin:0 0 22px 33px;font-size:13px}.session-body .goal{font-size:14px}.filter-row{gap:12px 16px;font-size:11px}.filter-row select{font-size:11px;max-width:142px}.filter-row .text-button{margin-left:0}.search{padding:8px 11px}.search input{font-size:13px}.search kbd{display:none}.resource{grid-template-columns:24px minmax(0,1fr);gap:9px 10px;padding:20px 0}.resource .row-number{font-size:17px;padding-top:3px}.resource h3{font-size:21px}.resource .save-button{grid-column:2;justify-self:start;margin:0}.english-title{font-size:11px}.row-summary{font-size:13px;line-height:1.85}.row-meta{font-size:10px;gap:6px 11px}.calc-inputs{grid-template-columns:1fr 1fr;gap:14px}.calc-inputs label{font-size:11px}.calc-inputs .button{align-self:end;height:48px}.calc-result{grid-template-columns:1fr;gap:10px;padding-top:22px}.calc-total{font-size:35px}.calc-result svg{max-height:140px}.formula{font-size:12px}.method{grid-template-columns:1fr;gap:24px}.method>div{display:grid;grid-template-columns:30px minmax(0,1fr);gap:0 14px}.method h3{margin:0 0 7px;font-size:21px}.method p{grid-column:2;font-size:13px}.detail{padding-top:25px}.detail-back{margin-bottom:24px}.detail h1{font-size:31px}.detail .english-title{font-size:13px}.detail .row-meta{font-size:11px}.detail-section h2{font-size:23px}.detail-section p,.detail-section ul,.detail-section ol{font-size:14px}.detail-question{font-size:20px!important}.detail .actions{gap:14px}.detail .save-button{font-size:12px;padding:9px 12px}.session-body .model-tags a{font-size:11px}.detail-footer{font-size:12px}.notice{font-size:12px;padding:12px 14px}.notebook-head{align-items:center}.notebook-head>.text-button{padding-top:0}#notes{padding:13px 15px;font-size:13px}}
.source-collection{border-top:1px solid var(--line);padding-top:16px}.source-collection>summary{font:700 21px/1.7 var(--serif);cursor:pointer;margin-bottom:14px}.source-collection[open]>summary{margin-bottom:18px}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
.lesson-feature{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:28px;align-items:center;border-top:2px solid var(--accent)}.lesson-feature h2{font-size:32px;margin-bottom:15px}.lesson-feature p{font-size:14px;line-height:1.95;max-width:660px}.lesson-feature .small{font-size:12px;margin-bottom:0}.lesson-feature>.actions{align-items:flex-start;flex-direction:column;gap:13px}.lesson-inline,.lesson-callout{padding:20px 24px;background:var(--wash);border-left:2px solid var(--accent);margin:22px 0}.lesson-inline p{margin-bottom:8px;font-size:14px}.lesson-inline p:last-child{margin-bottom:0;font-size:12px}.lesson-inline a{text-decoration:underline;text-underline-offset:3px}.lesson-callout h2{font-size:27px;margin-bottom:12px}.lesson-callout p{font-size:14px;line-height:1.9}.lesson-callout .eyebrow{font-size:10px;color:var(--accent)}.detail .lesson-callout .actions{border:0;padding:0;margin-top:20px}
@media(max-width:700px){.lesson-feature{grid-template-columns:1fr;gap:20px}.lesson-feature>.actions{flex-direction:row;align-items:center}.lesson-feature h2{font-size:28px}.lesson-inline,.lesson-callout{padding:17px 18px}.lesson-callout h2{font-size:24px}}