@import"https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Noto+Sans+SC:wght@400;500;600;700&display=swap";:root{font-family:Noto Sans SC,PingFang SC,sans-serif;color:#17232b;background:#f4f7f7;font-synthesis:none;text-rendering:optimizeLegibility;--ink: #17232b;--muted: #77848b;--line: #e6ebeb;--teal: #0a8c89;--teal-deep: #0c7070;--teal-soft: #e9f7f5;--navy: #17242d;--amber: #d59830}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh;-webkit-font-smoothing:antialiased;background:#f4f7f7}button,input,textarea{font:inherit}button,a{-webkit-tap-highlight-color:transparent}a{color:inherit;text-decoration:none}button{border:0;background:none;cursor:pointer;color:inherit}.app-frame{min-height:100vh;display:flex}.brand{display:inline-flex;align-items:center;gap:10px;font:700 26px/1 DM Sans,sans-serif;letter-spacing:0}.admin-sidebar .brand{padding:0 24px;color:#fff}.brand-mark{width:28px;height:28px;display:grid;grid-template-columns:repeat(3,1fr);gap:2px;align-items:end}.brand-mark span{background:#2bbd9f;border-radius:2px;display:block}.brand-mark span:nth-child(1){height:22px}.brand-mark span:nth-child(2){height:28px}.brand-mark span:nth-child(3){height:18px}.admin-sidebar>a{display:flex;align-items:center;gap:16px;padding:17px 26px;color:#b9c9ce;font-size:15px;transition:.2s}.admin-sidebar>a.active{color:#fff;background:#137d7d}.sidebar-achievement{margin:auto 24px 18px;border-top:1px solid rgba(255,255,255,.12);padding-top:20px;display:grid;gap:6px;color:#a9babd;font-size:12px}.sidebar-achievement strong{color:#f8c45c;font:700 21px/1 DM Sans,sans-serif}.sidebar-achievement small{font:500 11px Noto Sans SC;color:#b3c2c4}.sidebar-settings{display:flex;align-items:center;gap:8px;padding:10px 24px;color:#8da0a4;font-size:12px}.main-column{min-width:0;flex:1}.topbar{height:78px;padding:0 32px;background:#fff;border-bottom:1px solid var(--line);display:flex;align-items:center;gap:42px}.topbar>.brand{flex:0 0 auto;color:var(--ink);font-size:22px}.topbar>.brand .brand-mark{width:24px;height:24px}.topbar>.brand .brand-mark span:nth-child(1){height:19px}.topbar>.brand .brand-mark span:nth-child(2){height:24px}.topbar>.brand .brand-mark span:nth-child(3){height:16px}.top-nav{display:flex;align-items:center;gap:34px;height:100%}.top-nav a{color:#6a777e;font-size:14px;position:relative;height:100%;display:flex;align-items:center}.top-nav a.active{color:var(--ink);font-weight:600}.top-nav a.active:after{content:"";position:absolute;height:3px;background:var(--teal);left:0;right:0;bottom:-1px}.top-actions{margin-left:auto;display:flex;align-items:center;gap:30px}.search{display:flex;align-items:center;gap:10px;color:#9aa5aa;font-size:13px}.admin-entry{display:inline-flex;align-items:center;gap:6px;color:#167e7d;font-size:13px;font-weight:600}.auth-user-chip{display:inline-flex;align-items:center;gap:8px;max-width:220px;border:1px solid #dce7e5;border-radius:999px;padding:5px 8px 5px 5px;background:#f7fbfa;color:#445257;font-size:12px}.auth-user-chip>span{width:24px;height:24px;border-radius:50%;display:inline-flex;align-items:center;justify-content:center;background:var(--teal);color:#fff;font-weight:700}.auth-user-chip strong{min-width:0;max-width:96px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.auth-user-chip button{color:#167e7d;font-weight:700}.auth-loading,.auth-callback{min-height:100vh;display:grid;place-content:center;justify-items:center;gap:12px;padding:28px;color:#435259;background:radial-gradient(circle at 50% 0,rgba(10,140,137,.12),transparent 34%),#f4f7f7;text-align:center}.auth-loading strong,.auth-callback h1{margin:0;color:var(--ink);font-size:22px}.auth-callback p{max-width:420px;margin:0;color:var(--muted)}.auth-callback.error svg{color:#b45245}.login-page{min-height:100vh;display:grid;place-items:center;padding:28px;background:radial-gradient(circle at 18% 12%,rgba(18,164,160,.16),transparent 30%),radial-gradient(circle at 84% 18%,rgba(211,173,97,.16),transparent 28%),#f4f7f7}.login-card{width:min(420px,100%);padding:34px;border:1px solid var(--line);border-radius:8px;background:#fff;box-shadow:0 18px 60px #17242d1a}.login-card .brand{width:fit-content;margin-bottom:24px;color:var(--ink)}.login-card h1{margin:8px 0 10px;color:var(--ink);font-size:26px;letter-spacing:-.04em}.login-card p{margin:0 0 24px;color:var(--muted);line-height:1.7}.login-form{display:grid;gap:16px}.login-form label{display:grid;gap:7px;color:#4c5a5f;font-size:13px;font-weight:700}.login-form input{width:100%;border:1px solid #dde7e5;border-radius:6px;padding:12px 13px;color:var(--ink);font:inherit;outline:none;background:#fbfdfd}.login-form input:focus{border-color:var(--teal);box-shadow:0 0 0 3px #12a4a01f}.readonly-input,input[readonly].readonly-input{cursor:default;background:#f4f7f7;color:#66757a}.login-form .button{justify-content:center;min-height:44px}.login-form .button:disabled{cursor:not-allowed;opacity:.72}.login-error{border:1px solid #f0c7bd;border-radius:6px;padding:10px 12px;background:#fff5f2;color:#a24535;font-size:13px;line-height:1.5}.page-content{max-width:1400px;margin:0 auto;padding:32px 36px 72px}.breadcrumbs{display:flex;align-items:center;gap:7px;color:#899397;font-size:13px;margin-bottom:25px}.course-hero{background:#fff;border:1px solid var(--line);display:grid;grid-template-columns:122px minmax(0,1fr) 190px;gap:24px;padding:28px;align-items:center}.course-hero>img{width:122px;height:122px;object-fit:cover;border-radius:5px}.eyebrow{display:block;color:#849296;font:600 10px/1.4 DM Sans,sans-serif;letter-spacing:.13em;text-transform:uppercase}.course-hero-copy h1{margin:8px 0 7px;font-size:clamp(24px,2.6vw,35px);line-height:1.2;letter-spacing:0}.course-hero-labels{display:flex;align-items:center;gap:9px}.course-hero-copy p:not(.eyebrow){margin:0;color:#8a7370;font-size:14px}.hero-progress{margin-top:18px;display:grid;gap:8px;max-width:540px;font-size:12px;color:#718087}.hero-progress b{color:var(--ink)}.progress-track,.mini-track{height:8px;background:#e8eeee;border-radius:99px;overflow:hidden}.progress-track i,.mini-track i{display:block;height:100%;background:#168c8b;border-radius:inherit}.continue-card{display:flex;align-items:stretch;flex-direction:column;gap:8px}.continue-card>span,.continue-card>small{color:#8c9396;font-size:11px}.button{min-height:40px;display:inline-flex;align-items:center;justify-content:center;gap:8px;border-radius:4px;padding:0 16px;font-size:13px;font-weight:600;transition:.2s}.button-primary{color:#fff;background:#128b89}.button-primary:hover{background:#0a7272}.button-secondary{border:1px solid #d7e0df;background:#fff;color:#53646a}.button-secondary:hover{background:#f4f9f8}.button:disabled{opacity:.45;cursor:not-allowed}.course-tabs{display:flex;gap:34px;border-bottom:1px solid var(--line);margin-top:18px}.course-tabs button{padding:15px 2px 13px;position:relative;color:#839095;font-size:13px}.course-tabs button.active{color:var(--teal-deep);font-weight:600}.course-tabs button.active:after{content:"";position:absolute;height:2px;background:var(--teal);left:0;right:0;bottom:-1px}.course-tabs em{font-style:normal;font-size:11px;margin-left:4px;color:#9da8aa}.course-layout{display:grid;grid-template-columns:minmax(0,1fr);gap:36px;margin-top:25px}.section-heading,.panel-heading{display:flex;align-items:end;justify-content:space-between}.section-heading h2,.panel-heading h2{margin:6px 0 0;font-size:19px}.muted,.panel-heading>span{color:#99a5a8;font-size:12px}.chapter{border-bottom:1px solid var(--line)}.lesson-group-title{padding:11px 18px 9px 72px;color:#5f7478;background:#f7faf9;border-top:1px solid var(--line);font-size:12px;font-weight:600}.lesson-group .lesson-row{padding-left:88px}.chapter-heading{width:100%;padding:18px 2px;display:flex;align-items:center;gap:13px;text-align:left}.chapter-marker{width:29px;height:29px;border:1px solid #a9c9c8;color:#157c7b;border-radius:50%;display:inline-flex;align-items:center;justify-content:center;font:600 11px DM Sans,sans-serif}.chapter-heading strong{font-size:15px;flex:1}.chapter-chevron{color:#7b8e91;transition:transform .2s}.chapter.expanded .chapter-chevron{transform:rotate(180deg)}.lesson-list{margin:-2px 0 9px 42px}.lesson-row{min-height:58px;display:grid;grid-template-columns:minmax(0,1fr) 76px;gap:12px;align-items:center;border-top:1px solid #edf1f0;font-size:13px;color:#4d5c62}.lesson-row:hover{color:var(--teal-deep);background:#f4fbfa}.lesson-row-copy{min-width:0;display:grid;gap:4px;padding:9px 0}.lesson-title{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.lesson-details{min-width:0;display:flex;align-items:center;gap:10px;color:#879497;font-size:11px}.lesson-details>span:first-child{display:block;width:100%;min-width:0;max-width:100%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.lesson-contributor{flex:0 0 auto;color:#557b79}.lesson-type{justify-self:end;display:inline-flex;align-items:center;gap:6px;color:#839095;font-size:12px;white-space:nowrap}.lesson-state{justify-self:end;color:#a1abad;font-size:12px}.lesson-state.done{color:var(--teal)}.syllabus-foot{display:flex;flex-wrap:wrap;gap:25px;color:#8e9b9e;font-size:12px;padding:25px 0}.progress-rail{border-left:1px solid var(--line);padding-left:25px}.rail-title{display:flex;justify-content:space-between;align-items:center}.rail-title span{display:inline-flex;align-items:center;gap:8px;font-weight:600;font-size:14px}.rail-title b{color:#ef7057;font:600 12px DM Sans}.donut{width:122px;height:122px;border-radius:50%;background:conic-gradient(#148e8d var(--progress),#dbe7e6 0);margin:27px auto 19px;display:grid;place-content:center;text-align:center;position:relative}.donut:after{content:"";position:absolute;top:11px;right:11px;bottom:11px;left:11px;border-radius:50%;background:#fff}.donut strong,.donut span{position:relative;z-index:1}.donut strong{font:700 24px DM Sans}.donut span{font-size:11px;color:#879397}.progress-legend{display:grid;gap:9px;font-size:12px;color:#78858a}.progress-legend span{display:flex;gap:8px;align-items:center}.progress-legend b{margin-left:auto;color:#52646a;font-weight:500}.dot{width:8px;height:8px;border-radius:50%}.dot.teal{background:var(--teal)}.dot.gray{background:#9eafae}.dot.pale{background:#d8dfdf}.rail-divider{height:1px;background:var(--line);margin:25px 0}.progress-rail h3{margin:0 0 8px;font-size:13px}.rail-current{display:block;font-size:13px}.progress-rail p,.progress-rail small{color:#829094;font-size:11px;line-height:1.6}.progress-rail .mini-track{height:5px;margin:14px 0 6px}.recent-list{display:grid;gap:12px;margin-top:14px}.recent-list span{display:flex;gap:8px;align-items:center;font-size:12px;color:#637177}.text-link{display:inline-flex;align-items:center;gap:4px;color:var(--teal-deep);font-size:12px;margin-top:17px}.page-title-row{display:flex;align-items:end;justify-content:space-between;margin-bottom:28px}.page-title-row h1{margin:7px 0 5px;font-size:30px}.page-title-row p{margin:0;color:#78868b;font-size:13px}.catalog-filter{display:inline-flex;gap:10px;align-items:center;border:1px solid var(--line);background:#fff;padding:10px 13px;color:#617176;font-size:12px}.course-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:17px}.catalog-card{background:#fff;border:1px solid var(--line);padding:17px;display:grid;grid-template-columns:92px 1fr;gap:17px;transition:.2s}.catalog-card:hover{border-color:#9bc8c3;transform:translateY(-2px)}.catalog-card img{width:92px;height:92px;object-fit:cover;border-radius:4px}.catalog-card h2{font-size:17px;margin:10px 0 5px}.catalog-card p{margin:0;color:#879297;font-size:12px}.status-chip{display:inline-flex;background:var(--teal-soft);color:var(--teal-deep);padding:4px 8px;font-size:10px;border-radius:3px}.course-source-badge{display:inline-flex;align-items:center;min-height:22px;padding:3px 8px;border:1px solid transparent;border-radius:3px;font-size:10px;font-weight:600;line-height:1}.course-source-badge.official{border-color:#b9ddd8;background:#eaf8f5;color:#137c73}.course-source-badge.shared{border-color:#eed1ad;background:#fff4e8;color:#9a5c1c}.course-source-badge.compact{min-height:18px;margin-top:6px;padding:2px 6px;font-size:9px}.catalog-meta{display:flex;gap:15px;margin-top:16px;color:#8a999b;font-size:11px}.catalog-meta span{display:inline-flex;gap:5px;align-items:center}.empty-state,.error-state{text-align:center;padding:90px 20px;color:#849194}.empty-state h2,.error-state h2{color:var(--ink);font-size:20px;margin:13px 0 6px}.empty-state p{margin:0 0 20px}.history-panel{background:#fff;border:1px solid var(--line)}.history-head,.history-row{display:grid;grid-template-columns:1fr 240px 18px;gap:20px;align-items:center;padding:16px 22px}.history-head{color:#889497;font-size:12px;border-bottom:1px solid var(--line)}.history-row{min-height:91px;border-bottom:1px solid #eef2f1}.history-row>div:first-child{display:flex;align-items:center;gap:14px}.history-row img{width:52px;height:52px;object-fit:cover;border-radius:4px}.history-row strong,.history-row span{display:block}.history-row strong{font-size:14px}.history-row span{color:#909da0;font-size:11px;margin-top:6px}.history-progress{display:grid;gap:7px}.history-progress span{color:var(--teal-deep);margin:0;font-size:12px}.history-progress .progress-track{height:6px}.lesson-page{min-height:calc(100vh - 78px);padding:24px 32px 50px;background:#f8fbfa}.lesson-breadcrumb{display:flex;align-items:center;gap:8px;color:#8c989b;font-size:12px;margin-bottom:19px}.lesson-breadcrumb a{display:inline-flex;align-items:center;gap:6px;color:var(--teal-deep)}.lesson-workspace{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:18px;align-items:start;max-width:1580px;margin:0 auto}.lesson-main{min-width:0}.lesson-header{background:#fff;padding:25px 30px 22px;border:1px solid var(--line)}.lesson-header h1{margin:10px 0 7px;font-size:25px}.lesson-title-row{display:flex;align-items:center;justify-content:space-between;gap:24px}.lesson-title-row h1{min-width:0}.lesson-header-actions{display:flex;align-items:center;gap:8px;flex:0 0 auto}.lesson-nav-mobile{display:none}.lesson-header-actions .button{min-width:92px;min-height:38px;padding:0 14px;font-size:12px}.lesson-header p{margin:0;color:#829094;font-size:13px;line-height:1.7}.lesson-header-contributor{display:inline-flex;margin-top:9px;color:#477a76;font-size:12px;font-weight:600}.video-stage,.document-viewer{margin-top:15px;background:#fff;border:1px solid var(--line)}.video-stage{background:#111}.video-stage video{display:block;width:100%;aspect-ratio:16/9;object-fit:contain;background:#111}.video-caption{display:flex;justify-content:space-between;gap:15px;padding:12px 17px;color:#9eaaab;font-size:11px}.video-caption span:first-child{display:inline-flex;gap:6px;align-items:center;color:#d5dfdd}.document-viewer{min-height:450px;padding:32px 40px}.pdf-reader{margin-top:15px;border:1px solid var(--line);background:#fff;outline:none}.pdf-reader:focus-visible{box-shadow:0 0 0 2px #00918c2e}.pdf-reader-toolbar{min-height:54px;padding:8px 12px 8px 16px;display:flex;align-items:center;justify-content:space-between;gap:12px;border-bottom:1px solid var(--line)}.pdf-reader-toolbar>strong{overflow:hidden;color:#314148;font-size:13px;font-weight:600;text-overflow:ellipsis;white-space:nowrap}.pdf-page-controls{display:flex;align-items:center;gap:10px}.pdf-page-controls button,.pdf-download{width:36px;height:36px;border:1px solid var(--line);background:#fff;color:#476063;display:inline-flex;align-items:center;justify-content:center}.pdf-page-controls button:hover:not(:disabled),.pdf-download:hover{border-color:var(--teal);color:var(--teal-deep);background:#f1faf9}.pdf-page-controls button:disabled{cursor:not-allowed;color:#bdc7c8;background:#f7f9f9}.pdf-page-controls span{min-width:66px;color:#849194;font-size:12px;text-align:center}.pdf-page-controls b{color:#26383c;font-size:14px}.pdf-download{flex:0 0 auto}.pdf-page-stage{position:relative;padding:24px;overflow:auto;display:flex;align-items:flex-start;justify-content:center;background:#20292b}.pdf-page-stage canvas{display:block;max-width:100%;height:auto;background:#fff;box-shadow:0 5px 18px #00000047}.pdf-reader-footer{min-height:56px;padding:9px 12px;display:flex;align-items:center;justify-content:center;border-top:1px solid var(--line);background:#fff}.pdf-page-loading{position:absolute;top:0;right:0;bottom:0;left:0;z-index:1;display:flex;align-items:center;justify-content:center;color:#d9e1e1;font-size:13px;background:#20292bb8}.attachment-fallback{min-height:360px;margin-top:15px;padding:48px 24px;border:1px solid var(--line);background:#fff;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:12px;text-align:center;color:#738285}.attachment-fallback strong{color:#314148;font-size:16px}.attachment-fallback .button{margin-top:8px}.markdown-viewer{color:#314148;line-height:1.85;font-size:15px}.markdown-viewer h1{font-size:27px;margin:0 0 20px}.markdown-viewer h2{font-size:20px;margin:30px 0 8px}.markdown-viewer h3{font-size:16px;margin:22px 0 4px}.markdown-viewer blockquote{border-left:3px solid var(--teal);padding-left:16px;color:#678081;background:#f5fbfa;margin-left:0}.markdown-viewer li{margin:5px 0}.lesson-bottom{margin-top:15px;border:1px solid var(--line);background:#fff}.lesson-tabs{display:flex;gap:26px;padding:0 24px;border-bottom:1px solid var(--line)}.lesson-tabs button{padding:15px 0 13px;font-size:13px;color:#869397;position:relative}.lesson-tabs button.active{color:var(--teal-deep);font-weight:600}.lesson-tabs button.active:after{content:"";position:absolute;left:0;right:0;bottom:-1px;height:2px;background:var(--teal)}.lesson-view-tabs{margin-top:15px;background:#fff;border:1px solid var(--line)}.lesson-view-tabs button{min-width:92px}.tab-empty{margin-top:15px;min-height:190px;display:grid;place-items:center;border:1px solid var(--line);background:#fff;color:#8b999c;font-size:13px}.summary-generation-state{min-height:220px;margin-top:15px;display:flex;align-items:center;justify-content:center;flex-direction:column;gap:9px;padding:28px;border:1px solid var(--line);background:#fff;color:#71918f;text-align:center}.summary-generation-state strong{color:#314b4b;font-size:15px}.summary-generation-state p{max-width:460px;margin:0;color:#879597;font-size:12px;line-height:1.6}.summary-generation-state .button{margin-top:5px}.ppt-viewer{margin-top:15px;border:1px solid var(--line);background:#fff;padding:20px}.ppt-slide{min-height:430px;padding:42px 48px 28px;display:flex;flex-direction:column;background:#173b3d;color:#f4fbf9}.ppt-kicker{color:#92d5c4;font:600 11px DM Sans,sans-serif;letter-spacing:.11em;text-transform:uppercase}.ppt-slide h2{max-width:720px;margin:28px 0 13px;font-size:clamp(27px,3vw,42px);line-height:1.18}.ppt-slide p{max-width:670px;margin:0;color:#c4dcda;font-size:15px;line-height:1.8}.ppt-points{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:auto;padding-top:42px}.ppt-points>div{border-top:1px solid rgba(209,241,232,.3);padding-top:11px;display:grid;gap:7px}.ppt-points span{color:#91d5c3;font:600 12px DM Sans,sans-serif}.ppt-points strong{font-size:14px;font-weight:500}.ppt-footer{display:flex;justify-content:space-between;margin-top:31px;color:#92b8b2;font-size:11px}.ppt-controls{display:flex;align-items:center;justify-content:space-between;padding-top:15px}.ppt-controls .button{min-width:80px}.ppt-dots{display:flex;gap:7px;align-items:center}.ppt-dots button{width:7px;height:7px;padding:0;border-radius:50%;background:#cbd8d6}.ppt-dots button.active{width:21px;border-radius:99px;background:var(--teal)}.comments-panel{margin-top:15px;border:1px solid var(--line);background:#fff;padding:22px 24px 26px}.knowledge-qa{position:sticky;top:18px;height:min(720px,calc(100vh - 114px));min-height:540px;border:1px solid var(--line);background:#fff;display:grid;grid-template-rows:auto minmax(0,1fr) auto}.knowledge-qa-modal{display:contents}.knowledge-qa-fab{display:none}.knowledge-qa-header{min-height:72px;padding:15px 16px;border-bottom:1px solid var(--line);display:grid;grid-template-columns:36px minmax(0,1fr) auto;gap:10px;align-items:center}.knowledge-qa-icon{width:36px;height:36px;display:grid;place-items:center;border-radius:5px;background:var(--teal-soft);color:var(--teal-deep)}.knowledge-qa-header h2{margin:0 0 4px;font-size:15px}.knowledge-qa-header div>span{display:flex;align-items:center;gap:6px;color:#8a979a;font-size:10px}.knowledge-qa-header div>span:before{content:"";width:6px;height:6px;flex:0 0 auto;border-radius:50%;background:#c7a35d}.knowledge-qa-header div>span.ready:before{background:#20a783}.knowledge-qa-refresh{width:32px;height:32px;display:inline-flex;align-items:center;justify-content:center;color:#7a898c}.knowledge-qa-header-actions{display:flex;align-items:center;gap:2px}.knowledge-qa-close{display:none}.knowledge-qa-refresh:hover,.knowledge-qa-close:hover{color:var(--teal-deep);background:#f2f8f7}.knowledge-qa-messages{min-height:0;padding:16px;overflow-y:auto;background:#fbfdfd;scrollbar-width:thin}.knowledge-message{display:flex;flex-direction:column;align-items:flex-start;margin-bottom:13px}.knowledge-message.user{align-items:flex-end}.knowledge-message-content{max-width:91%;padding:10px 12px;border:1px solid #e1e9e8;border-radius:6px;background:#fff;color:#435359;font-size:12px;line-height:1.7;overflow-wrap:anywhere}.knowledge-message.user .knowledge-message-content{border-color:#c4e1dc;background:#eaf7f4;color:#244a49}.knowledge-message.error .knowledge-message-content{border-color:#ead2cd;background:#fff7f5;color:#9d5548}.knowledge-message-content p{margin:0 0 8px}.knowledge-message-content p:last-child,.knowledge-message-content ul:last-child,.knowledge-message-content ol:last-child{margin-bottom:0}.knowledge-message-content ul,.knowledge-message-content ol{margin:7px 0;padding-left:18px}.knowledge-message-images{width:91%;margin-top:7px;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:7px}.knowledge-message-images button{min-width:0;padding:0;overflow:hidden;border:1px solid #dce7e5;border-radius:5px;background:#fff;color:#647779;text-align:left}.knowledge-message-images button:hover{border-color:#8fc7bf;color:var(--teal-deep)}.knowledge-message-images img{display:block;width:100%;aspect-ratio:16 / 9;object-fit:contain;background:#f3f6f5}.knowledge-message-images span{display:block;padding:5px 7px;overflow:hidden;font-size:9px;white-space:nowrap;text-overflow:ellipsis}.knowledge-image-preview{position:fixed;top:0;right:0;bottom:0;left:0;z-index:120;padding:24px;display:grid;grid-template-rows:auto minmax(0,1fr);background:#101719eb}.knowledge-image-preview-toolbar{min-height:44px;display:flex;align-items:center;justify-content:space-between;gap:16px;color:#eef6f4;font-size:12px}.knowledge-image-preview-toolbar span{overflow:hidden;white-space:nowrap;text-overflow:ellipsis}.knowledge-image-preview-toolbar button{width:36px;height:36px;flex:0 0 auto;display:grid;place-items:center;color:#eef6f4;background:#ffffff1a}.knowledge-image-preview-toolbar button:hover{background:#ffffff2e}.knowledge-image-preview-stage{min-height:0;display:grid;place-items:center}.knowledge-image-preview-stage img{display:block;max-width:100%;max-height:100%;object-fit:contain}.knowledge-sources{max-width:91%;margin-top:6px;display:flex;flex-wrap:wrap;gap:5px;align-items:center}.knowledge-sources>span{color:#96a1a3;font-size:9px}.knowledge-sources small{max-width:100%;padding:3px 6px;border:1px solid #dde8e6;background:#fff;color:#6f8083;font-size:9px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.knowledge-suggestions{display:grid;gap:7px;margin-top:5px}.knowledge-suggestions button{min-height:34px;padding:7px 10px;border:1px solid #dce8e6;border-radius:4px;background:#fff;color:#5f7275;font-size:11px;line-height:1.45;text-align:left}.knowledge-suggestions button:hover{border-color:#9dcfc8;color:var(--teal-deep);background:#f3faf8}.knowledge-message.pending{width:48px;min-height:32px;padding:0 10px;border:1px solid #e1e9e8;border-radius:6px;background:#fff;display:flex;flex-direction:row;align-items:center;justify-content:center;gap:4px}.knowledge-message.pending span{width:5px;height:5px;border-radius:50%;background:#7fa8a3;animation:qa-pulse 1.1s infinite ease-in-out}.knowledge-message.pending span:nth-child(2){animation-delay:.14s}.knowledge-message.pending span:nth-child(3){animation-delay:.28s}@keyframes qa-pulse{0%,60%,to{opacity:.35;transform:translateY(0)}30%{opacity:1;transform:translateY(-2px)}}.knowledge-qa-composer{min-height:80px;padding:11px;border-top:1px solid var(--line);background:#fff;display:grid;grid-template-columns:minmax(0,1fr) 36px;gap:7px;align-items:end}.knowledge-qa-composer textarea{width:100%;min-height:54px;max-height:112px;padding:9px 10px;border:1px solid #d8e3e1;border-radius:4px;outline-color:var(--teal);resize:none;color:var(--ink);font-size:12px;line-height:1.55}.knowledge-qa-composer textarea:disabled{background:#f5f7f7;color:#9da7a8}.knowledge-qa-composer button{width:36px;height:36px;border-radius:4px;background:var(--teal);color:#fff;display:inline-flex;align-items:center;justify-content:center}.knowledge-qa-composer button:hover:not(:disabled){background:var(--teal-deep)}.knowledge-qa-composer button:disabled{cursor:not-allowed;background:#c7d2d0}.comments-heading{display:flex;align-items:end;justify-content:space-between;padding-bottom:16px;border-bottom:1px solid var(--line)}.comments-heading h2{margin:7px 0 0;display:flex;align-items:center;gap:7px;font-size:17px}.comments-heading>span{color:#8b999c;font-size:12px}.comment-form{padding:17px 0 20px;border-bottom:1px solid var(--line)}.comment-fields{display:grid;gap:9px}.comment-fields input,.comment-fields textarea{width:100%;border:1px solid #d6e2e0;background:#fbfdfd;padding:10px 11px;outline-color:var(--teal);color:var(--ink);font-size:13px}.comment-fields input{max-width:230px}.comment-fields textarea{min-height:90px;resize:vertical;line-height:1.7}.comment-submit{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-top:10px}.comment-submit small{color:#8e9b9d;font-size:11px}.comment-submit .button{min-height:36px}.comment-list{display:grid}.comment-item{display:flex;gap:11px;padding:17px 0;border-bottom:1px solid #eef2f1}.comment-item:last-child{border-bottom:0;padding-bottom:0}.comment-avatar{width:29px;height:29px;display:grid;place-items:center;flex:0 0 auto;border-radius:50%;background:var(--teal-soft);color:var(--teal-deep);font-size:12px;font-weight:600}.comment-item strong{font-size:12px}.comment-item time{margin-left:9px;color:#a0abad;font-size:10px}.comment-item p{margin:6px 0 0;color:#657479;font-size:13px;line-height:1.7;white-space:pre-wrap}.lesson-copy{padding:22px 24px;color:#637278;font-size:13px;line-height:1.7}.lesson-copy h2{margin:0 0 8px;color:var(--ink);font-size:16px}.lesson-copy ul{padding-left:20px}.attachment-row{display:flex;align-items:center;gap:10px;border-top:1px solid var(--line);padding-top:16px}.attachment-row small{margin-left:auto;color:#9aa4a6}.notes-input{width:100%;min-height:120px;border:1px solid var(--line);resize:vertical;padding:12px;color:var(--ink);outline-color:var(--teal)}.admin-shell{min-height:100vh;display:flex;background:#f2f6f5}.admin-sidebar{width:215px;flex:0 0 215px;background:var(--navy);color:#d7e5e6;padding:24px 0;display:flex;flex-direction:column}.admin-sidebar .brand{margin-bottom:50px}.admin-label{color:#81999c;font:600 10px DM Sans;letter-spacing:.14em;padding:0 25px 13px}.admin-sidebar>a{font-size:13px;padding:15px 25px}.admin-sidebar>a.disabled-link{opacity:.55}.admin-footer{margin:auto 25px 6px;border-top:1px solid rgba(255,255,255,.12);padding-top:17px;display:grid;gap:6px}.admin-footer span,.admin-footer small{color:#8ea5a7;font-size:11px}.admin-footer strong{color:#fff;font-size:12px}.admin-main{min-width:0;flex:1}.admin-topbar{min-height:124px;background:#fff;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;align-items:center;padding:25px 38px}.admin-topbar h1{margin:7px 0 0;font-size:27px}.admin-top-actions{display:flex;align-items:center;gap:20px}.admin-top-actions>a{display:inline-flex;align-items:center;gap:6px;color:#6c7d81;font-size:12px}.admin-body{padding:30px 38px 60px;max-width:1440px}.admin-metrics{display:grid;grid-template-columns:repeat(4,1fr);gap:15px;margin-bottom:22px}.admin-metrics>div{background:#fff;border:1px solid var(--line);padding:20px 21px}.admin-metrics span{display:block;color:#849194;font-size:11px;margin-bottom:9px}.admin-metrics strong{font:700 27px DM Sans}.admin-metrics small{color:#8c989a;font-size:11px;margin-left:5px}.admin-content-grid{display:grid;grid-template-columns:300px minmax(0,1fr);gap:18px;align-items:start}.permissions-body{max-width:900px}.permissions-panel{background:#fff;border:1px solid var(--line);padding:24px}.permission-form{display:flex;align-items:flex-end;gap:12px;padding:22px 0;border-bottom:1px solid var(--line)}.permission-form label{display:grid;gap:8px;flex:1;color:#617174;font-size:12px}.permission-form input{width:100%;height:42px;border:1px solid var(--line);padding:0 12px;font:inherit}.permission-list{display:grid}.permission-row{min-height:68px;display:grid;grid-template-columns:38px 1fr 36px;align-items:center;gap:12px;border-bottom:1px solid var(--line)}.permission-avatar{width:36px;height:36px;display:grid;place-items:center;background:#e7f1ef;color:#1f665d;font-weight:700}.permission-row div{display:grid;gap:4px}.permission-row small{color:#879497}.icon-danger-button{width:34px;height:34px;display:grid;place-items:center;border:0;background:transparent;color:#a44b4b;cursor:pointer}.admin-course-list,.admin-tree-panel{background:#fff;border:1px solid var(--line)}.panel-heading{padding:20px 21px;border-bottom:1px solid var(--line);min-height:77px}.panel-heading h2{font-size:17px}.course-select-row{width:100%;display:grid;grid-template-columns:52px minmax(0,1fr) 17px;gap:11px;align-items:center;text-align:left;padding:14px 17px;border-bottom:1px solid #edf1f0}.course-select-row:hover,.course-select-row.active{background:#eff9f7}.course-select-row.active{border-left:3px solid var(--teal);padding-left:14px}.course-select-row img{width:52px;height:52px;border-radius:3px;object-fit:cover}.course-select-row strong,.course-select-row small{display:block}.course-select-row strong{font-size:12px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.course-select-row small{color:#8a999b;font-size:10px;margin-top:5px}.tree-actions{display:flex;gap:7px}.course-status-button{border:1px solid #b7d9d4;background:#eaf8f5;color:#137c73}.course-status-button.published{border-color:#e1c9a8;background:#fff8ed;color:#9b6824}.tree-actions .button{padding:0 10px;font-size:11px}.tree-table-head,.tree-row{display:grid;grid-template-columns:minmax(0,1fr) 54px 60px 132px;gap:10px;align-items:center}.tree-table-head{color:#9aa5a7;font-size:10px;padding:12px 20px;background:#fafcfc}.tree-row{min-height:60px;border-top:1px solid #edf1f0;padding-top:8px;padding-right:20px;padding-bottom:8px;font-size:12px}.tree-name{display:flex;align-items:center;gap:8px;min-width:0}.tree-name svg{flex:0 0 auto;color:#7f9293}.tree-name-copy{min-width:0;display:grid;gap:4px}.tree-name-copy span,.tree-name-copy small{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.tree-name-copy small{color:#93a0a2;font-size:10px;font-weight:400}.tree-type{color:#8b999b;font-size:11px}.status-toggle{justify-self:start;color:#8b999b;font-size:10px;padding:4px 5px;border-radius:3px}.status-toggle.published{color:#168b81;background:#eaf8f5}.status-toggle.draft{color:#bb822b;background:#fff7e8}.tree-row-actions{display:flex;gap:5px;justify-content:flex-end}.tree-row-actions button,.node-upload-action{color:#8a9899;padding:4px;display:inline-flex;align-items:center;justify-content:center;cursor:pointer}.node-upload-action.is-disabled{cursor:not-allowed;opacity:.55;pointer-events:none}.node-upload-action.is-uploading{gap:5px;padding-inline:7px;color:var(--teal-deep);background:var(--teal-soft);font-size:11px;white-space:nowrap;opacity:1}.upload-spinner{animation:upload-spin .8s linear infinite}@keyframes upload-spin{to{transform:rotate(360deg)}}.tree-row-actions button:hover,.node-upload-action:hover,.tree-row-actions .has-content,.node-upload-action.has-content{color:var(--teal-deep);background:var(--teal-soft)}.tree-row-actions button[title=删除]:hover{color:#c45d54;background:#fff3f1}.inline-folder-form{display:grid;grid-template-columns:minmax(180px,.8fr) minmax(260px,1.2fr) auto;align-items:start;gap:8px;padding:12px 20px;border-bottom:1px solid var(--line);background:#fbfdfc}.inline-folder-form input,.inline-folder-form textarea{width:100%;border:1px solid #cadad8;padding:8px 10px;font-size:12px;outline-color:var(--teal)}.inline-folder-form textarea{min-height:68px;resize:vertical;line-height:1.6}.inline-folder-actions{display:flex;gap:8px}.inline-folder-form button{display:inline-flex;align-items:center;gap:4px;color:var(--teal-deep);font-size:12px}.inline-folder-form button:disabled{opacity:.45;cursor:not-allowed}.admin-empty{padding:35px 20px;text-align:center;color:#98a3a5;font-size:12px}.toast{position:fixed;right:25px;bottom:25px;color:#fff;background:#173334;padding:12px 17px;font-size:12px;border-radius:4px;box-shadow:0 7px 20px #112b2b2e}.modal-backdrop{position:fixed;top:0;right:0;bottom:0;left:0;background:#0e1c206e;display:grid;place-items:center;padding:20px;z-index:10}.modal{width:min(460px,100%);background:#fff;padding:28px;position:relative}.modal-close{position:absolute;right:17px;top:17px;color:#8d999c}.modal h2{margin:8px 0 5px;font-size:21px}.modal>p{margin:0 0 21px;color:#819094;font-size:12px}.course-source-field{display:grid;gap:7px;margin-top:15px;color:#5f7074;font-size:12px}.course-source-options{display:grid;grid-template-columns:1fr 1fr;gap:0;padding:3px;border:1px solid #d7e2e0;background:#f6f9f8}.course-source-options button{min-height:34px;color:#778689;font-size:12px;font-weight:600}.course-source-options button.active.official{background:#e5f5f2;color:#137c73}.course-source-options button.active.shared{background:#fff0df;color:#955818}.modal label{display:grid;gap:7px;color:#5f7074;font-size:12px;margin-top:15px}.modal input,.modal textarea{width:100%;border:1px solid #d7e2e0;padding:10px 11px;outline-color:var(--teal);font-size:13px}.modal textarea{min-height:84px;resize:vertical}.summary-modal{width:min(820px,100%);max-height:calc(100vh - 40px);overflow:auto}.summary-editor-field{display:grid;gap:7px;margin-top:15px;color:#5f7074;font-size:12px}.rich-text-editor,.rich-text-loading{border:1px solid #d7e2e0;background:#fff}.rich-text-loading{min-height:280px;padding:18px;color:#8a9899}.rich-text-toolbar{min-height:45px;padding:5px 7px;display:flex;align-items:center;gap:3px;flex-wrap:wrap;border-bottom:1px solid #e3e9e8;background:#f8fafa}.rich-text-toolbar button{width:34px;height:34px;display:inline-flex;align-items:center;justify-content:center;color:#66777a;border:1px solid transparent}.rich-text-toolbar button:hover:not(:disabled),.rich-text-toolbar button.active{color:var(--teal-deep);border-color:#b9dcd7;background:#eaf8f5}.rich-text-toolbar button:disabled{color:#bdc6c7;cursor:not-allowed}.rich-text-toolbar-divider{width:1px;height:24px;margin:0 4px;background:#dce4e3}.rich-text-upload-status{max-width:120px;overflow:hidden;color:#718285;font-size:11px;text-overflow:ellipsis;white-space:nowrap}.rich-text-content{min-height:290px;max-height:52vh;padding:18px 20px;overflow:auto;outline:none;color:#314148;font-size:14px;line-height:1.75}.rich-text-content h2{margin:22px 0 8px;font-size:20px}.rich-text-content p{margin:8px 0}.rich-text-content blockquote{margin:14px 0;padding:8px 14px;border-left:3px solid var(--teal);background:#f3faf8;color:#627779}.rich-text-content img,.markdown-viewer img{display:block;max-width:100%;height:auto;margin:18px auto}.rich-text-content a,.markdown-viewer a{color:var(--teal-deep);text-decoration:underline}.modal-actions{display:flex;justify-content:end;gap:8px;margin-top:24px}.shared-course-modal{width:min(640px,100%);max-height:calc(100vh - 40px);overflow:auto}.share-chapter-field{display:grid;gap:7px;margin-top:15px;color:#5f7074;font-size:12px}.share-mode-options{display:grid;grid-template-columns:1fr 1fr;gap:0;padding:3px;border:1px solid #d7e2e0;background:#f6f9f8}.share-mode-options button{min-height:35px;display:inline-flex;align-items:center;justify-content:center;gap:6px;color:#778689;font-size:12px;font-weight:600}.share-mode-options button.active{color:var(--teal-deep);background:#e5f5f2}.share-mode-options button:disabled{cursor:not-allowed;opacity:.5}.share-chapter-field select,.share-chapter-field input{width:100%;min-height:41px;border:1px solid #d7e2e0;padding:9px 11px;outline-color:var(--teal);background:#fff;color:#314148;font-size:13px}.share-file-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:15px}.modal .share-file-field{min-width:0;margin:0;padding:12px;border:1px solid #d7e2e0;background:#fafcfc}.share-file-field>span{display:inline-flex;align-items:center;gap:7px;color:#40575a;font-weight:600}.modal .share-file-field input[type=file]{padding:7px;background:#fff;font-size:11px}.share-file-field small,.share-file-requirement{color:#8a9799;font-size:11px;line-height:1.5}.shared-course-modal .share-file-requirement{margin:8px 0 0}.form-error{margin-top:13px;padding:9px 11px;border-left:3px solid #c65f55;background:#fff3f1;color:#a54841;font-size:12px}.share-notice{color:#35736e!important;text-align:center}.loading-rows{display:grid;gap:12px;padding:25px 0}.loading-rows span{display:block;height:35px;background:linear-gradient(90deg,#eff3f2 25%,#f8fbfa,#eff3f2 75%);background-size:200% 100%;animation:load 1.4s infinite}@keyframes load{to{background-position:-200% 0}}@media(max-width:1120px){.topbar{padding:0 20px;gap:22px}.top-nav{gap:19px}.search{display:none}.course-layout{grid-template-columns:minmax(0,1fr) 220px;gap:22px}.admin-content-grid{grid-template-columns:260px minmax(0,1fr)}.lesson-workspace{grid-template-columns:minmax(0,1fr) 310px;gap:14px}}@media(max-width:980px){.lesson-workspace{display:block}.knowledge-qa-fab{position:fixed;right:16px;bottom:calc(18px + env(safe-area-inset-bottom));z-index:90;width:54px;height:54px;border:1px solid rgba(255,255,255,.5);border-radius:50%;background:var(--teal);color:#fff;box-shadow:0 7px 22px #0c707047;display:inline-flex;align-items:center;justify-content:center}.knowledge-qa-fab:after{content:"";position:absolute;top:5px;right:5px;width:8px;height:8px;border:2px solid var(--teal);border-radius:50%;background:#d3ad61}.knowledge-qa-fab.ready:after{background:#6ee2bb}.knowledge-qa-modal{display:none}.knowledge-qa-modal.open{position:fixed;top:0;right:0;bottom:0;left:0;z-index:100;padding:18px 8px calc(8px + env(safe-area-inset-bottom));display:flex;align-items:flex-end;justify-content:center;background:#1322267a}.knowledge-qa{position:relative;top:auto;width:min(100%,480px);height:min(680px,82dvh);min-height:0;margin:0;border-radius:8px;overflow:hidden;box-shadow:0 16px 45px #10222538}.knowledge-qa-close{width:32px;height:32px;display:inline-flex;align-items:center;justify-content:center;color:#7a898c}.knowledge-qa-composer{padding-bottom:calc(11px + env(safe-area-inset-bottom))}}@media(max-width:820px){.admin-sidebar{display:none}.topbar>.brand{font-size:20px}.topbar>.brand .brand-mark{transform:scale(.76);transform-origin:left center;width:22px;margin-right:-4px}.topbar{height:65px;padding:0 16px;gap:20px}.top-nav{margin-left:auto;gap:15px}.top-nav a{font-size:12px}.admin-entry{font-size:0}.admin-entry svg{width:19px}.auth-user-chip{gap:4px;padding-right:5px}.auth-user-chip strong{display:none}.auth-user-chip button{font-size:0}.auth-user-chip button:after{content:"退";font-size:12px}.page-content{padding:24px 18px 60px}.course-hero{grid-template-columns:78px 1fr;gap:16px;padding:18px}.course-hero>img{width:78px;height:78px}.course-hero-copy h1{font-size:21px}.course-hero-copy p:not(.eyebrow){font-size:12px}.continue-card{grid-column:1 / -1;width:100%;flex-direction:row;flex-wrap:wrap}.continue-card .button{flex:1 1 160px}.continue-card .share-notice{flex-basis:100%}.course-layout{display:block}.progress-rail{border:0;border-top:1px solid var(--line);padding:28px 0 0;margin-top:25px}.donut{margin-left:0}.lesson-row{grid-template-columns:minmax(0,1fr) 67px}.lesson-details{align-items:flex-start;flex-direction:column;gap:2px}.lesson-contributor{flex:auto}.lesson-state{display:none}.page-title-row{display:block}.catalog-filter{margin-top:18px;display:inline-flex}.course-grid{grid-template-columns:1fr}.lesson-page{padding:18px 12px 40px}.lesson-workspace{display:block}.lesson-header{padding:19px}.lesson-header h1{font-size:21px}.lesson-title-row{display:block}.lesson-title-row h1{margin-bottom:0}.lesson-nav-desktop{display:none}.lesson-nav-mobile{width:100%;display:flex;margin-top:16px}.lesson-header-actions .button{flex:1 1 0}.ppt-slide{min-height:380px;padding:28px 24px 22px}.ppt-points{grid-template-columns:1fr;gap:12px;padding-top:28px}.ppt-points>div{grid-template-columns:28px 1fr;align-items:baseline}.comments-panel{padding:18px 16px 21px}.comment-submit{align-items:flex-end;flex-direction:column}.comment-submit .button{align-self:flex-end}.document-viewer{padding:23px 18px}.pdf-reader-toolbar{padding-left:12px}.pdf-page-stage{padding:12px}.admin-topbar,.admin-body{padding-left:18px;padding-right:18px}.admin-topbar{align-items:flex-start;flex-direction:column;gap:14px}.admin-top-actions{width:100%;justify-content:space-between}.admin-metrics{grid-template-columns:repeat(2,1fr)}.admin-content-grid{grid-template-columns:1fr}.tree-actions{flex-wrap:wrap}.tree-table-head,.tree-row{grid-template-columns:minmax(0,1fr) 48px 132px}.tree-row-actions{grid-column:3;grid-row:1;justify-self:end}.tree-table-head span:last-child{display:none}.tree-type{font-size:10px}.status-toggle{display:none}.history-head,.history-row{grid-template-columns:1fr 90px 15px;gap:9px;padding:14px}.history-progress .progress-track{display:none}}@media(max-width:600px){.shared-course-modal{padding:22px 18px}.share-file-grid{grid-template-columns:1fr}}@media(max-width:460px){.top-nav a:nth-child(3){display:none}.topbar{gap:11px}.top-nav{gap:12px}.course-tabs{gap:17px;overflow:auto}.course-tabs button{white-space:nowrap}.lesson-breadcrumb{overflow:auto;white-space:nowrap}.admin-metrics{gap:8px}.admin-metrics>div{padding:14px}.tree-actions .button{font-size:10px}.panel-heading{padding:16px}.tree-table-head{padding:10px 14px}.tree-row{padding-right:14px}.catalog-card{grid-template-columns:78px 1fr;padding:13px}.catalog-card img{width:78px;height:78px}}