:root{--blue:#244ce5;--ink:#202226;--muted:#727782;--line:#e1e4eb;--paper:#f7f8fa}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:Arial,PingFang SC,Microsoft YaHei,sans-serif;font-size:16px;line-height:1.6}a{color:inherit;text-decoration:none}button,textarea{font:inherit}a,button{-webkit-tap-highlight-color:transparent}button{cursor:pointer}a:focus-visible,button:focus-visible,textarea:focus-visible{outline:3px solid #8cafff;outline-offset:4px}button{transition:background .18s,color .18s}header.header{height:92px;justify-content:space-between;gap:24px;padding:0 4.5%;border-bottom:1px solid var(--line);background:#fff}.brand,header.header{display:flex;align-items:center}.brand{gap:18px}.brandmark{font-weight:800;font-size:20px;letter-spacing:-1px}.brandmark span{color:var(--blue);padding:0 3px}.brandname{font-size:14px;border-left:1px solid var(--line);padding-left:18px;font-weight:600}nav{gap:34px;height:100%;align-items:stretch}nav,nav a{display:flex}nav a{align-items:center;border-bottom:3px solid transparent;font-size:14px;color:var(--muted);padding-top:3px}nav a.active{color:var(--blue);border-color:var(--blue);font-weight:700}.version{font-size:12px;letter-spacing:1px;color:var(--muted)}.version span{margin-left:8px;letter-spacing:0}.home,.learning{max-width:1400px;margin:auto;padding:52px 5% 0}.eyebrow{font-size:12px;letter-spacing:2px;font-weight:700;color:var(--blue)}.intro{display:flex;justify-content:space-between;align-items:center;padding:40px 0 52px}.course-label{font-size:14px;margin:0 0 18px;color:var(--muted)}.intro h1{font-size:clamp(42px,5.2vw,72px);line-height:1.2;letter-spacing:-2px;margin:0;font-weight:700}.intro h1 span{font-weight:400}.intro h1 i{color:var(--blue);font-style:normal}.intro-copy{color:var(--muted);margin:24px 0 0}.course-index{display:flex;flex-direction:column;align-items:center;padding:0 5%;border-left:1px solid var(--line)}.course-index span{font-size:12px;letter-spacing:3px}.course-index strong{font-size:144px;color:var(--blue);font-weight:400;line-height:1.3;letter-spacing:-10px}.week-card{background:white;border:1px solid var(--line);border-top:3px solid var(--blue);padding:30px 36px 34px}.week-heading{display:flex;justify-content:space-between;align-items:center}.pill{font-size:12px;color:var(--muted);padding:4px 10px;border:1px solid var(--line);border-radius:30px}.week-layout{display:grid;grid-template-columns:1fr 1fr;grid-gap:50px;gap:50px;margin-top:24px}.week-title>p:first-child{font-size:14px;color:var(--muted);margin-top:0}.week-title h2{font-size:32px;line-height:1.3;margin:12px 0}.muted{color:var(--muted);font-size:14px}.primary{border:1px solid var(--blue);background:var(--blue);color:white;border-radius:4px;padding:10px 16px;font-size:14px;font-weight:600;display:inline-flex;align-items:center;justify-content:center}.primary:hover{background:#1737b5}.enter{margin-top:20px;gap:42px;padding:13px 20px}.enter span{font-size:22px}.task-overview{border-left:1px solid var(--line);padding-left:36px}.task-overview h3{font-size:14px;margin:0 0 12px}.task-overview ol{padding:0;margin:0;list-style:none}.task-overview li{display:flex;gap:18px;align-items:center;padding:14px 0;border-bottom:1px solid var(--line)}.task-overview li:last-child{border:0}.task-overview li>span{font-size:13px;color:var(--blue)}.task-overview strong{font-size:16px;font-weight:500}.task-overview p{font-size:14px;color:var(--muted);margin:2px 0 0}.task-overview small{margin-left:auto;white-space:nowrap}.task-overview small,footer{color:var(--muted);font-size:12px}footer{display:flex;justify-content:space-between;gap:20px;margin-top:45px;padding:24px 0;border-top:1px solid var(--line)}.learning{padding-top:34px}.chapter-heading{display:flex;justify-content:space-between;align-items:center}.chapter-heading .eyebrow{color:var(--muted);letter-spacing:1px}.chapter-heading h1{font-size:30px;margin:12px 0 26px}.chapter-heading h1 span{font-size:16px;color:var(--muted);font-weight:400;margin-right:22px}.stage-bar{display:flex;border-bottom:1px solid var(--line);gap:36px}.stage-bar button{border:0;border-bottom:3px solid transparent;background:none;padding:13px 8px;color:var(--muted);font-weight:600;font-size:16px;min-width:108px}.stage-bar button span{font-size:12px;margin-right:12px;font-weight:400}.stage-bar button.selected{color:var(--blue);border-color:var(--blue)}.stage-guide{font-size:14px;color:var(--muted);margin:20px 0}.study-grid{display:grid;grid-template-columns:minmax(0,65fr) minmax(0,35fr);grid-gap:24px;gap:24px;align-items:start}.reader,.tasks{background:#fff;border:1px solid var(--line);border-radius:6px;overflow:hidden}.panel-heading{display:flex;justify-content:space-between;align-items:center;gap:8px;border-bottom:1px solid var(--line);padding:17px 22px}.panel-heading h2{font-size:16px;margin:0;font-weight:600}.panel-heading>span{font-size:12px;color:var(--muted)}.pdf-area{background:#edf0f5;padding:36px;min-height:850px;display:flex;align-items:stretch}.pdf-paper{width:100%;background:#fff;border:1px solid #e4e7ed;box-shadow:0 8px 24px #17234008;padding:40px 28px;display:flex;align-items:center;flex-direction:column;justify-content:center;text-align:center}.pdf-label{color:#949aa4;font-size:12px;letter-spacing:2px;margin-bottom:76px}.document-icon{border:1px solid #b9c5ee;border-radius:4px;color:var(--blue);padding:26px 14px;font-size:15px;background:#f7f9ff}.pdf-paper h3{font-size:22px;font-weight:500;margin:24px 0 4px}.pdf-paper p{font-size:14px;color:var(--muted);margin:0}.placeholder-lines{margin:34px 0;width:62%;display:grid;grid-gap:12px;gap:12px}.placeholder-lines i{height:5px;background:#eef0f4}.placeholder-lines i:last-child{width:65%;justify-self:center}.pdf-paper small{margin-top:40px}.pdf-paper small,.reader-foot{font-size:12px;color:var(--muted)}.reader-foot{padding:15px 22px;display:flex;justify-content:space-between}.task-note{font-size:14px;color:var(--muted);margin:18px 22px}.question{padding:0 22px 18px;margin-bottom:18px;border-bottom:1px solid var(--line)}.question label{font-size:15px;display:block;line-height:1.75;font-weight:500}.question-num{display:block;color:var(--blue);font-size:12px;letter-spacing:1px;margin-bottom:4px}textarea{display:block;width:100%;resize:vertical;border:1px solid #dce0e8;border-radius:4px;background:#fbfcfe;min-height:102px;padding:12px;font-size:14px;line-height:1.65;color:var(--ink);margin:12px 0}textarea::placeholder{color:#9298a2}.answer-actions{display:flex;gap:10px;flex-wrap:wrap}.answer-actions button{padding:8px 13px}.secondary{background:white;border:1px solid #dce0e8;border-radius:4px;font-size:14px;color:var(--blue)}.secondary:hover{background:#f0f4ff}.response-message{font-size:13px;color:var(--blue);margin:8px 0 0;line-height:1.6}.response-message:empty{display:none}.prototype-note{font-size:12px;color:var(--muted);margin:0 22px 18px}.discussion{margin-top:30px;background:#fff;border:1px solid var(--line);border-radius:6px;padding:0 26px 22px}.discussion-top{display:flex;gap:26px;border-bottom:1px solid var(--line);align-items:center}.discussion-top button{background:none;border:0;border-bottom:2px solid transparent;padding:18px 0;font-size:16px;color:var(--muted)}.discussion-top button.chosen{color:var(--blue);border-color:var(--blue);font-weight:600}.discussion-top>span{margin-left:auto;color:var(--muted);font-size:12px}.discussion-label{display:block;margin-top:22px;font-size:14px}.discussion textarea{min-height:90px}.discussion .muted{font-size:12px;margin-bottom:0}@media(min-width:1500px){.home,.learning{padding-left:40px;padding-right:40px}}@media(max-width:1000px){.brandname{display:none}.study-grid{grid-template-columns:minmax(0,60fr) minmax(0,40fr)}.pdf-area{padding:20px}.week-layout{gap:26px}.task-overview{padding-left:26px}.version span{display:none}.question{padding-left:16px;padding-right:16px}}@media(max-width:700px){header.header{height:76px;padding:0 5%;gap:12px}.brandmark{font-size:16px}nav{gap:18px}nav a{font-size:14px}.version{display:none}.home,.learning{padding:28px 5% 0}.intro{padding:30px 0 36px}.intro h1{font-size:42px}.intro-copy{font-size:14px;max-width:230px}.course-index{padding:0 0 0 16px}.course-index strong{font-size:72px;letter-spacing:-6px}.course-index span{font-size:10px;letter-spacing:1px}.course-index span:last-child{display:none}.week-card{padding:22px}.week-layout{grid-template-columns:1fr;gap:28px}.task-overview{border-left:0;border-top:1px solid var(--line);padding:24px 0 0}.study-grid{grid-template-columns:1fr}.pdf-area{min-height:480px;padding:20px}.pdf-paper{padding:24px}.pdf-label{margin-bottom:30px}.pdf-paper small{margin-top:16px}.stage-bar{gap:12px;justify-content:space-between}.stage-bar button{min-width:0;flex:1 1}.chapter-heading h1{font-size:24px}.chapter-heading h1 span{font-size:14px;margin-right:12px}.chapter-heading .eyebrow{font-size:11px}.chapter-heading>.pill{display:none}.discussion{padding:0 18px 18px}.discussion-top>span{display:none}footer{flex-direction:column;gap:6px;margin-top:30px}}.pdf-upload{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px 24px;background:#fff;border:1px solid var(--line);padding:26px 30px;margin-top:24px;border-radius:6px}.pdf-upload>div:first-child{min-width:0;flex:1 1}.pdf-upload h3{font-size:18px;margin:6px 0;overflow-wrap:anywhere}.pdf-upload p{margin:4px 0}.upload-actions{display:flex;gap:12px;flex-wrap:wrap}.upload-actions button{padding:11px 18px}.upload-note{font-size:12px;color:var(--muted)}.pdf-upload .response-message,.upload-note{flex-basis:100%}.pdf-upload.compact{margin:0;border:0;border-top:1px solid var(--line);border-radius:0;padding:20px}.compact h3{font-size:14px}.compact .eyebrow{font-size:12px}.pdf-frame{display:block;width:100%;height:850px;border:0;background:#edf0f5}.pdf-filename{padding:12px 20px;font-size:14px;overflow-wrap:anywhere;background:#f4f6fc}.reader-foot a{color:var(--blue)}.phase-intro{padding:24px 0 28px}.phase-intro h2{font-size:22px;margin:0 0 6px}.phase-intro>p{font-size:14px;color:var(--muted);margin:0 0 20px}.phase-intro ol{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));grid-gap:22px;gap:22px;padding:0;list-style:none;margin:0}.phase-intro li{font-size:14px;border-top:1px solid var(--line);padding-top:12px}.phase-intro li span{color:var(--blue);font-size:12px;margin-right:10px}.phase-nav{display:flex;justify-content:flex-end;gap:12px;margin-top:24px}.phase-nav .secondary{padding:10px 16px}.review{padding:26px;background:white;border:1px solid var(--line);margin-top:28px;border-radius:6px}.review h2{font-size:22px;margin:0}.review h3{font-size:16px;color:var(--blue);margin-top:26px}.review-item{padding:14px 0;border-top:1px solid var(--line)}.review-item strong{font-size:14px;font-weight:500}.review-item p{white-space:pre-wrap;overflow-wrap:anywhere;font-size:14px;color:var(--muted);margin:8px 0 0}button:disabled{cursor:wait;opacity:.6}@media(max-width:700px){.phase-intro ol{grid-template-columns:1fr;gap:10px}.pdf-upload{padding:20px}.pdf-upload>div:first-child{flex-basis:100%}.pdf-frame{height:65vh;min-height:400px}.phase-intro h2{font-size:20px}}.case-hero{display:flex;justify-content:space-between;align-items:center;gap:24px;padding:8px 0 28px}.case-hero h1{font-size:40px;margin:12px 0;line-height:1.4}.case-hero h1 span{display:block;font-size:22px;font-weight:400;margin-top:8px}.library-boundary{display:flex;gap:20px;border-left:3px solid var(--blue);padding:16px 20px;background:#edf2ff;font-size:14px;margin-bottom:32px}.library-boundary strong{white-space:nowrap;color:var(--blue)}.library-boundary span{color:#525e77}.case-list-heading,.case-section-heading{display:flex;justify-content:space-between;align-items:center;gap:20px;margin:24px 0 16px}.case-list-heading h2,.case-section-heading h2{font-size:22px;margin:0}.case-list-heading h2 span{font-size:14px;color:var(--muted);margin-left:10px;font-weight:400}.case-search{width:320px}.case-library input:not([type=file]),.case-library select{display:block;width:100%;padding:11px 13px;border:1px solid #dce0e8;border-radius:4px;font:inherit;font-size:14px;background:#fff;color:var(--ink);min-width:0}.case-library input:focus-visible,.case-library select:focus-visible{outline:3px solid #8cafff;outline-offset:2px}.case-filters{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:24px}.case-filters button{border:1px solid var(--line);background:white;border-radius:30px;padding:7px 16px;font-size:14px;color:var(--muted)}.case-filters button.selected{background:var(--ink);color:white;border-color:var(--ink)}.case-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));grid-gap:22px;gap:22px;align-items:start;margin-top:18px}.case-card{background:white;border:1px solid var(--line);border-radius:6px;overflow:hidden;min-width:0}.case-card-top{background:#eaf0ff;display:flex;justify-content:space-between;align-items:center;padding:24px;color:var(--blue);min-height:122px}.case-card-top>span:first-child{font-size:14px}.case-number{font-size:54px;line-height:1;font-weight:400;letter-spacing:-3px}.case-card:nth-child(2n) .case-card-top{background:#edf1f3;color:#355166}.case-card-body{padding:24px}.case-meta{display:flex;justify-content:space-between;gap:12px;font-size:12px;color:var(--muted)}.case-card h3{font-size:22px;line-height:1.55;margin:18px 0 10px;overflow-wrap:anywhere}.case-summary{font-size:14px;color:var(--muted);white-space:pre-wrap;overflow-wrap:anywhere}.case-concept{color:var(--blue);font-size:12px;background:#f2f5ff;padding:8px 10px;overflow-wrap:anywhere}.case-card summary{cursor:pointer;padding:16px 0;font-size:14px;border-top:1px solid var(--line);list-style:none}.case-card summary span{float:right}.case-card summary::-webkit-details-marker{display:none}.case-detail{padding-bottom:10px}.case-detail h4{font-size:14px;margin:14px 0 6px}.case-detail p{font-size:14px;white-space:pre-wrap;overflow-wrap:anywhere;color:#566071;margin:0}.case-credit{border-top:1px solid var(--line);padding-top:16px;display:flex;justify-content:space-between;gap:12px;font-size:12px;color:var(--muted);overflow-wrap:anywhere}.case-cover{display:block;width:100%;height:220px;object-fit:contain;background:#edf0f5}.case-attachments{font-size:14px;padding-left:18px;overflow-wrap:anywhere}.case-attachments a{color:var(--blue);text-decoration:underline}.case-empty{padding:50px;text-align:center;border:1px dashed var(--line)}.case-empty button{padding:10px 16px}.case-form-section{background:#fff;border:1px solid var(--line);padding:28px;border-radius:6px;margin-bottom:36px}.case-section-heading{margin-top:0}.case-section-heading button{padding:8px 12px;white-space:nowrap}.case-form-grid{display:grid;grid-template-columns:1fr 1fr;grid-gap:20px;gap:20px}.case-form-grid label{font-size:14px;min-width:0}.case-form-grid label>input,.case-form-grid label>select{margin-top:8px}.case-form-grid .wide{grid-column:1/-1}.case-form-grid textarea{margin-bottom:0}.case-form-grid small{display:block;color:var(--muted);margin-top:10px;font-size:12px}.case-form-grid input[type=file]{display:block;width:100%;font-size:14px;padding:16px;background:#f6f8fc;border:1px dashed #bdc8df;border-radius:4px}.form-submit{display:flex;justify-content:space-between;align-items:center;gap:20px}.form-submit button{flex-shrink:0}.form-error{color:#ac2637;font-size:14px}.selected-files{list-style:none;padding:0;font-size:14px}.selected-files li{display:flex;justify-content:space-between;gap:15px;padding:8px 0;border-bottom:1px solid var(--line);overflow-wrap:anywhere}.text-button{border:0;background:none;color:var(--blue);font-size:14px;flex-shrink:0}.case-entry{display:flex;justify-content:space-between;align-items:center;gap:24px;border-top:1px solid var(--line);padding-top:28px;margin-top:36px}.case-entry h2{font-size:24px;margin:10px 0}.case-entry .primary{flex-shrink:0}.study-case-link{display:flex;justify-content:space-between;gap:20px;margin-top:28px;padding:20px;background:#edf2ff;font-size:14px}.study-case-link a{color:var(--blue);font-weight:600}.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}@media(max-width:1150px){.header .brandname{display:none}.case-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:700px){.case-entry,.case-hero,.form-submit,.library-boundary{flex-direction:column;align-items:flex-start}.case-hero h1{font-size:32px}.case-form-grid,.case-grid{grid-template-columns:1fr}.case-form-grid .wide{grid-column:auto}.case-list-heading{align-items:flex-start;flex-direction:column}.case-search{width:100%}.case-form-section{padding:20px}.case-section-heading{align-items:flex-start}.case-section-heading h2{font-size:20px}.case-hero>.primary{width:100%}.study-case-link{flex-direction:column;gap:8px}header.header{flex-wrap:wrap;height:auto;padding-top:16px;gap:6px}.header .brand{flex-basis:100%}.header nav{gap:24px;height:48px}.case-library input[type=file]{font-size:12px}}html{scroll-padding-top:20px}body{min-height:100vh;min-height:100dvh;padding:env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left)}.pwa-controls{max-width:1280px;margin:0 auto;padding:14px 5% 28px;display:flex;gap:18px;flex-wrap:wrap;border-top:1px solid var(--line);font-size:14px;color:var(--muted)}.pwa-status{flex:1 1;min-width:220px}.pwa-status span{display:block;font-size:12px;margin-top:4px}.pwa-controls summary{cursor:pointer;color:var(--blue);padding:8px 0}.pwa-controls details{max-width:480px}.pwa-controls button{padding:10px 14px}.mobile-reading-tools{display:flex;justify-content:space-between;gap:16px;padding:12px 20px;background:#f4f6fc;color:var(--blue);font-size:14px}.mobile-reading-tools a{min-height:44px;display:flex;align-items:center}.study-grid>*{min-width:0}textarea{scroll-margin-block:24px}.question textarea{min-height:130px}.primary,.secondary,button{touch-action:manipulation}@media(max-width:1024px){.case-library input:not([type=file]),.case-library select,input,select,textarea{font-size:16px}.study-grid{grid-template-columns:1fr}.pdf-area{min-height:420px}.pdf-frame{height:65vh;height:65dvh;min-height:340px}.primary,.secondary,button{min-height:44px}.question{padding:0 22px 22px}.answer-actions button{flex:1 1}.question textarea{min-height:150px}.stage-bar{position:-webkit-sticky;position:sticky;top:0;background:var(--paper);z-index:5}.case-form-grid input[type=file]{font-size:16px}.reader-foot{flex-wrap:wrap;gap:8px}.pwa-controls{padding-bottom:24px}}@media(max-width:420px){.intro h1{font-size:36px}.course-index strong{font-size:60px}.home,.learning{padding-left:16px;padding-right:16px}.case-entry h2{font-size:21px}.stage-bar button{padding-left:4px;padding-right:4px}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}