:root{font-family:Inter,"Microsoft YaHei","PingFang SC",sans-serif;color:#1d302e;background:#f5f7f6;font-synthesis:none;--green:#12665b;--muted:#73837f;--border:#e4ebe7}*{box-sizing:border-box}body{margin:0}button,input,textarea,select{font:inherit}button,a,input,textarea,select{outline-offset:4px}button,a{touch-action:manipulation}button{cursor:pointer}button:disabled{opacity:.5;cursor:wait}a{color:inherit;text-decoration:none}input,textarea,select{border:1px solid #d8e2de;border-radius:8px;background:white;padding:11px 12px;color:#203832;width:100%}input:focus,textarea:focus,select:focus{outline:2px solid #9ec8be}textarea{resize:vertical;line-height:1.7}label{display:block;font-size:14px;font-weight:600;margin:19px 0 9px}h1,h2,h3,p{margin-top:0}h1{font-size:30px;font-weight:650;letter-spacing:-1px}h2{font-size:20px}h3{font-size:16px}p{line-height:1.8}small{font-size:12px;color:var(--muted)}.muted,.footnote{color:var(--muted);font-size:12px}.eyebrow{display:block;font-size:12px;letter-spacing:1.5px;font-weight:600;color:var(--green);margin-bottom:14px}.brand{display:flex;align-items:center;gap:12px;font-size:18px;letter-spacing:1px;font-weight:700}.brand small{display:block;font-size:11px;font-weight:400;letter-spacing:2px;margin-top:5px}.brand-icon{width:40px;height:40px;display:grid;place-items:center;background:var(--green);color:white;border-radius:12px 4px 12px 4px;font-size:23px;font-weight:500}.primary,.secondary,.upload-button{display:inline-flex;align-items:center;justify-content:center;gap:12px;border-radius:8px;padding:12px 18px;font-size:14px;font-weight:600;line-height:1.5;border:1px solid var(--border)}.primary{background:var(--green);border-color:var(--green);color:white}.primary:hover{background:#0c544a}.secondary,.upload-button{background:white;color:#244b41}.secondary:hover,.upload-button:hover{background:#f0f7f3}.text-button{border:0;background:none;color:var(--muted);padding:10px;font-size:13px}.danger{color:#aa443f}.welcome{min-height:100vh;display:grid;grid-template-columns:1.12fr 1fr}.welcome-story{background:#e8f0e9;padding:48px 8%;display:flex;flex-direction:column;position:relative;overflow:hidden}.welcome-story:after{content:'';position:absolute;width:440px;height:440px;border:70px solid #dde9df;border-radius:50%;bottom:-260px;right:-180px}.welcome-copy{margin:auto 0;padding:70px 0;z-index:1}.welcome-copy h1{font-size:clamp(30px,3.4vw,52px);line-height:1.55;margin:22px 0}.welcome-copy p{color:#59716a;font-size:15px}.welcome footer{color:#758c7f;font-size:12px}.flow{display:flex;align-items:center;gap:23px;margin-top:44px}.flow span{color:#729487;font-size:13px}.flow em{display:block;font-style:normal;font-size:13px;font-weight:600;color:#355f50;margin-top:8px}.flow i{font-style:normal;color:#95aa9f}.login-side{display:grid;place-items:center;background:#fcfdfb;padding:40px}.login-card{width:100%;max-width:360px}.login-card h2{font-size:25px}.login-card p{color:var(--muted);font-size:14px}.login-card button{margin-top:22px;width:100%;justify-content:space-between}.login-card>small{display:block;line-height:1.8;margin-top:34px}.form-error{color:#a43e38!important;min-height:1em}.workspace{display:flex;min-height:100vh}.sidebar{width:236px;flex-shrink:0;background:white;border-right:1px solid var(--border);padding:29px 19px;position:sticky;top:0;height:100vh;display:flex;flex-direction:column}.sidebar .brand{padding:0 8px 38px}.sidebar-label{font-size:11px;color:#90a199;letter-spacing:1.5px;padding:15px 15px 10px}.nav-item{width:100%;border:0;background:transparent;color:#657872;display:flex;align-items:center;text-align:left;gap:10px;padding:12px 14px;border-radius:8px;margin:3px 0;font-size:13px}.nav-item b{margin-left:auto;font-size:11px;font-weight:400}.nav-item.active{background:#eaf3ed;color:#12665b;font-weight:600}.sidebar-foot{margin-top:auto;padding:28px 12px 0;font-size:12px;color:#506b60}.sidebar-foot small{display:block;margin-top:12px;font-size:10px}.online-dot{display:inline-block;width:6px;height:6px;background:#58a88a;border-radius:50%;margin-right:7px}.main{flex:1;min-width:0}.topbar{height:72px;border-bottom:1px solid var(--border);display:flex;justify-content:space-between;align-items:center;padding:0 42px;background:#ffffff99;font-size:12px;color:#819189}.main-inner{max-width:1370px;margin:auto;padding:37px 42px}.page-title{display:flex;justify-content:space-between;align-items:center;gap:20px;margin-bottom:28px}.page-title h1{margin-bottom:10px}.page-title p{font-size:13px;color:var(--muted);margin:0}.page-title .eyebrow{font-size:10px;margin-bottom:10px}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-bottom:24px}.stats>div{background:white;border:1px solid var(--border);padding:21px 24px;border-radius:12px}.stats span{color:var(--muted);font-size:12px}.stats strong{display:block;font-size:32px;font-weight:550;margin-top:13px}.stats small{font-size:11px;font-weight:400;margin-left:9px}.notice{padding:14px 18px;background:#f2f0e5;border:1px solid #e9e5d2;border-radius:8px;font-size:12px;line-height:1.8;color:#827141;margin-bottom:24px;display:flex;gap:16px}.notice b{white-space:nowrap;font-weight:500}.library{background:white;border:1px solid var(--border);border-radius:12px;overflow:hidden}.toolbar{display:flex;align-items:center;justify-content:space-between;padding:21px 24px;gap:15px}.toolbar h2{font-size:15px;margin:0}.filters{display:flex;gap:10px}.filters input{font-size:12px;width:210px}.filters select{font-size:12px;width:126px}.table-wrap{overflow-x:auto}table{width:100%;border-collapse:collapse;text-align:left;font-size:12px;white-space:nowrap}th{background:#f8faf8;font-size:11px;letter-spacing:.4px;color:#82938a;font-weight:400;padding:14px 24px;border-block:1px solid var(--border)}td{padding:17px 24px;border-bottom:1px solid #edf1ee;color:#6d7e76}td:first-child{color:#233f34;white-space:normal;min-width:220px}td>small{display:block;font-size:10px;margin-top:5px}tbody tr:hover{background:#fcfdfb}.part-name{display:flex;align-items:center;gap:13px}.part-name b{font-size:12px;font-weight:500}.part-name small{display:block;font-size:10px;letter-spacing:1px;margin-top:6px}.part-icon{display:grid;place-items:center;flex-shrink:0;width:34px;height:34px;border:1px solid #e0e9e4;border-radius:8px;background:#f6f9f6;color:#57816c;font-size:22px}.badge{display:inline-block;font-size:10px;border-radius:20px;padding:5px 10px;white-space:nowrap}.badge.gray{background:#f0f3f1;color:#8a9a92}.badge.green{background:#e6f2e9;color:#387758}.badge.amber{background:#fcf2df;color:#a47a25}.manage{background:transparent;border:0;color:#346952;font-size:12px;padding:8px 0}.manage span{margin-left:12px}.table-foot{padding:17px 24px;font-size:10px;color:#8a9a91}.footnote{font-size:10px;margin-top:18px}.empty{text-align:center;padding:35px;white-space:normal}.empty-page{max-width:480px;margin:120px auto;padding:30px}.loading{padding:100px 25px;text-align:center;color:var(--muted)}dialog{width:min(1000px,95vw);max-height:92vh;border:1px solid var(--border);padding:0;border-radius:15px;color:inherit;box-shadow:0 24px 90px #10282033}dialog::backdrop{background:#102e2266;backdrop-filter:blur(3px)}.editor-header{display:flex;align-items:center;justify-content:space-between;padding:24px 30px;border-bottom:1px solid var(--border);background:white;position:sticky;top:0;z-index:1}.editor-header h2{margin:0;font-size:22px}.editor-header .eyebrow{font-size:10px;margin-bottom:8px}.close{width:35px;height:35px;border:0;background:#f2f5f2;border-radius:50%;font-size:25px;color:#647f6c}.editor-body{display:grid;grid-template-columns:1fr 270px}.editor-main{padding:6px 30px 30px}.editor-main label{font-size:12px}.editor-main input,.editor-main textarea{font-size:13px}.editor-main .secondary{margin-top:14px}#save-state{margin-left:12px}.publish-panel{padding:28px 24px;background:#f7f9f6;border-left:1px solid var(--border)}.publish-panel h3{font-size:15px}.publish-panel p{font-size:12px;color:var(--muted)}.publish-panel .primary{width:100%;margin-top:20px}.page-link{color:var(--green);font-size:12px;font-weight:600}.divider{height:1px;background:var(--border);margin:25px 0}.review-check{display:flex;align-items:flex-start;font-size:12px;line-height:1.9;font-weight:400;gap:8px}.review-check input{width:16px;height:16px;flex-shrink:0;margin-top:3px;accent-color:var(--green)}.small-notice{padding:12px;background:#ebeede;border-radius:7px;font-size:11px;line-height:1.8;color:#818b63}.part-url{display:block;font-size:10px;overflow-wrap:anywhere;color:#8b9a90;margin-top:15px}.video-section{margin-top:28px;border-top:1px solid var(--border);padding-top:22px}.section-title{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px}.section-title h3{margin:0}.video-empty{background:#f3f6f3;min-height:190px;border:1px dashed #cddcd1;border-radius:10px;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:20px;text-align:center}.video-empty>span{font-size:34px;color:#6b9482;margin-bottom:14px}.video-empty b{font-size:13px;font-weight:500}.video-empty p{font-size:11px;color:var(--muted);margin:9px 0 0}video{width:100%;background:#101e19;border-radius:8px;display:block;aspect-ratio:16/9}.media-info{font-size:11px;color:var(--muted);margin:10px 0}.upload-button{cursor:pointer;display:inline-flex}.file-input{position:absolute;width:1px;height:1px;opacity:0}.file-input:focus-visible+.muted{outline:2px solid var(--green)}#upload-progress{font-size:12px;color:var(--green)}#toast{position:fixed;bottom:25px;left:50%;transform:translateX(-50%) translateY(100px);padding:14px 23px;background:#153e31;color:white;border-radius:10px;font-size:13px;box-shadow:0 8px 30px #173b2722;z-index:100;opacity:0;transition:all .18s;max-width:90vw;pointer-events:none}#toast.show{transform:translateX(-50%);opacity:1}#toast.error{background:#98463e}.student{max-width:760px;margin:auto;padding:0 28px;background:#fcfdfb;min-height:100vh}.student>header{display:flex;align-items:center;justify-content:space-between;padding:25px 0;border-bottom:1px solid var(--border)}.student .brand{font-size:16px}.student .brand small{font-size:10px;letter-spacing:1px}.student-tag{font-size:10px;background:#edf3eb;color:#718772;padding:6px 9px;border-radius:5px}.lesson-title{padding:35px 0 12px}.lesson-title .eyebrow{font-size:10px}.lesson-title h1{font-size:30px;line-height:1.5;margin-bottom:10px}.lesson-title p{font-size:12px;color:var(--muted)}.player-wrap{background:#142b22;border-radius:12px;overflow:hidden}.player-caption{display:flex;justify-content:space-between;color:#85968a;font-size:10px;margin-top:12px}.lesson-section{display:flex;gap:18px;border-bottom:1px solid var(--border);padding:30px 0}.lesson-number{width:31px;height:31px;display:grid;place-items:center;border-radius:8px;background:#e7f0e7;color:#46795e;flex-shrink:0;font-size:12px}.lesson-number.amber{background:#f2edde;color:#9b813d}.lesson-section h2{font-size:17px;margin:4px 0 15px}.lesson-section p{font-size:14px;color:#5a7064;white-space:pre-line;margin-bottom:0;overflow-wrap:anywhere}.lesson-note{background:#f1f4ed;border-radius:9px;padding:18px 20px;font-size:12px;margin-top:25px}.lesson-note p{color:#71836e;white-space:pre-line;margin:8px 0 0}.student footer{padding:35px 0;text-align:center;font-size:10px;color:#9aaa9c;letter-spacing:1px}.student-empty{text-align:center;min-height:65vh;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:40px 15px}.empty-symbol{font-size:44px;width:90px;height:90px;border-radius:50%;background:#eef3e9;color:#819778;display:grid;place-items:center;margin-bottom:30px}.student-empty h1{font-size:25px}.student-empty p{font-size:13px;color:var(--muted)}.student-empty small{margin-top:30px;font-size:11px}#play-error{padding:12px;background:#fcf1df;border-radius:8px;margin-top:15px;font-size:12px}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
@media(min-width:1400px){.main-inner{padding-top:46px}.stats{gap:22px}.toolbar{padding:25px 28px}td{padding-top:20px;padding-bottom:20px}}@media(max-width:1050px){.sidebar{width:200px;padding:24px 12px}.sidebar .brand{font-size:15px}.main-inner{padding:28px 22px}.topbar{padding:0 22px}.stats>div{padding:18px}.page-title h1{font-size:26px}td,th{padding-left:17px;padding-right:17px}.editor-body{grid-template-columns:1fr 240px}.editor-main{padding-inline:22px}}@media(max-width:760px){.welcome{display:block}.welcome-story{padding:30px}.welcome-copy{padding:35px 0 20px}.welcome-copy h1{font-size:29px}.welcome-copy p,.flow,.welcome-story footer{display:none}.login-side{padding:36px 25px;min-height:50vh}.sidebar{display:none}.topbar{height:55px}.main-inner{padding:25px 16px}.page-title{align-items:flex-start}.page-title h1{font-size:23px}.page-title p{font-size:11px}.page-title .secondary{font-size:11px;padding:8px;white-space:nowrap}.stats{gap:10px;grid-template-columns:repeat(2,1fr)}.stats>div{padding:17px}.stats strong{font-size:27px;margin-top:8px}.notice{display:block;font-size:11px}.notice span{display:block;margin-top:5px}.toolbar{display:block;padding:17px}.filters{margin-top:16px}.filters input{width:100%;flex:1;min-width:80px}.filters select{width:115px}.editor-body{display:block}.editor-header{padding:19px}.editor-header h2{font-size:18px}.editor-main{padding:4px 19px 25px}.publish-panel{border-left:0;border-top:1px solid var(--border);padding:25px 19px}.student{padding:0 20px}.student>header{padding:20px 0}.lesson-title{padding-top:29px}.lesson-title h1{font-size:27px}.lesson-section{gap:12px}.lesson-section h2{font-size:16px}.lesson-section p{font-size:13px}.lesson-number{width:27px;height:27px;font-size:10px}}

@media(max-width:760px){.library th:nth-child(2),.library td:nth-child(2),.library th:nth-child(3),.library td:nth-child(3){display:none}.library th,.library td{padding:14px 10px}.library td:first-child{min-width:155px;width:55%}.library .part-name{gap:8px}.library .part-icon{width:27px;height:27px;font-size:18px}.library .manage span{margin-left:4px}.library .badge{padding:5px 7px}}

/* Student pages: quiet blue accents, a real video poster and touch-sized controls. */
.brand-logo{display:block;width:166px;height:auto;max-height:48px;object-fit:contain}.brand-subtitle{display:block;font-size:11px;font-weight:500;color:#6d7d91;border-left:1px solid #dce3eb;padding-left:12px;letter-spacing:1px;white-space:nowrap}.sidebar .brand{flex-wrap:wrap;gap:8px}.sidebar .brand-logo{width:154px}.sidebar .brand-subtitle{border:0;padding:0}.student{max-width:900px;padding:0 34px;background:#fff;color:#203044}.student>header{padding:23px 0;border-color:#e9eef3;min-height:82px}.student .brand{gap:12px}.student-back{font-size:12px;color:#52708c;padding:12px 0 12px 12px;white-space:nowrap}.lesson-title{padding:35px 0 14px}.lesson-kicker{display:flex;align-items:center;gap:14px;color:#446881;font-size:11px;letter-spacing:1px;margin-bottom:12px}.lesson-kicker>span{font-size:10px;letter-spacing:1.5px;color:#8a9bac;border-left:1px solid #dce4ed;padding-left:14px}.lesson-title h1{font-size:34px;letter-spacing:-.5px;line-height:1.4;margin-bottom:10px}.lesson-title p{font-size:13px;color:#8a98a6;margin-bottom:14px}.player-wrap{position:relative;background:#14212d;border-radius:14px;box-shadow:0 10px 30px #14212d10}.player-wrap video{background:#14212d;border-radius:0}.video-wait{position:absolute;top:16px;left:16px;background:#132335df;padding:8px 12px;color:white;font-size:12px;border-radius:6px;pointer-events:none}.video-wait[hidden]{display:none}.player-caption{font-size:11px;gap:12px;color:#8090a0;margin-top:13px;min-height:18px}.lesson-actions{display:flex;align-items:center;justify-content:space-between;padding:14px 0 22px;gap:12px}.lesson-action{font-size:12px;color:#365b78;border:1px solid #e1e8ef;background:#f8fafc;padding:11px 15px;border-radius:8px;min-height:44px}.speed-control{display:flex;align-items:center;gap:10px;color:#8090a0;font-size:11px;font-weight:400;margin:0}.speed-control select{font-size:12px;width:90px;padding:10px 9px;border-color:#e1e8ef;min-height:44px}.lesson-tabs{display:flex;border-bottom:1px solid #e6edf3;gap:28px;margin-top:6px}.lesson-tabs a{padding:13px 0;font-size:13px;color:#426b8d;min-height:44px}.lesson-tabs a:first-child{border-bottom:2px solid #2676b9}.student .lesson-section{padding:29px 0;scroll-margin-top:20px;border-color:#e9eef3}.student .lesson-number{background:#edf4fa;color:#3476aa}.student .lesson-number.amber{background:#f7f1e5;color:#a78546}.student .lesson-section h2{font-size:17px;color:#263d50;margin-bottom:12px}.student .lesson-section p{color:#667c8e;font-size:14px;line-height:1.95}.student .lesson-note{background:#f4f7fa;color:#516b81;border:1px solid #e9eef3}.student .lesson-note p{color:#788a9b;line-height:1.9}.more-lessons{display:flex;align-items:center;justify-content:space-between;padding:22px 0;font-size:14px;color:#2f648e;border-bottom:1px solid #e9eef3;margin-top:14px}.more-lessons small{display:block;color:#95a2af;font-size:11px;font-weight:400;margin-top:7px}.student footer{color:#a0adba;font-size:10px}.library-intro{padding:47px 0 25px}.library-intro h1{font-size:31px;line-height:1.55;letter-spacing:-.5px;margin:12px 0}.library-intro p{font-size:13px;color:#8293a3}.lesson-search{display:flex;gap:12px}.lesson-search input{flex:1;min-width:0;border-color:#e0e8ef;font-size:13px;padding:13px}.lesson-search select{width:154px;border-color:#e0e8ef;font-size:12px}.lesson-count{font-size:11px;color:#8b9aaa;margin:20px 0 14px}.lesson-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.lesson-card{border:1px solid #e3eaf0;border-radius:12px;background:#fff;padding:20px;transition:border-color .15s,box-shadow .15s}.lesson-card:hover{border-color:#95b5ce;box-shadow:0 7px 22px #2445600b}.card-id{display:flex;justify-content:space-between;font-size:10px;letter-spacing:1px;color:#9aa9b7}.card-id>span{letter-spacing:0}.lesson-card h2{font-size:16px;line-height:1.6;margin:19px 0 8px;font-weight:600}.lesson-card p{font-size:10px;color:#8a9dab;margin:0 0 23px}.card-go{display:flex;justify-content:space-between;color:#4681ab;font-size:11px}.lesson-grid>.empty{grid-column:1/-1}.student-tag{background:#f1f6fa;color:#7093ac}
@media(max-width:600px){.student{padding:0 18px}.student>header{padding:17px 0;min-height:72px}.student .brand-logo{width:132px}.student .brand-subtitle{font-size:10px;padding-left:9px}.student .brand{gap:9px}.student-back{font-size:11px}.lesson-title{padding-top:27px}.lesson-title h1{font-size:29px}.lesson-title p{font-size:12px}.player-wrap{border-radius:10px}.player-caption{font-size:10px;gap:8px}.lesson-actions{padding-bottom:12px}.student .lesson-section p{font-size:13px}.student .lesson-section h2{font-size:16px}.library-intro{padding-top:33px}.library-intro h1{font-size:27px}.lesson-search select{width:116px}.lesson-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:11px}.lesson-card{padding:16px}.lesson-card h2{font-size:14px;margin-top:16px}.library-page .student-tag{display:none}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}

.page-actions{display:flex;gap:10px;flex-wrap:wrap}

/* Student QR pages deliberately contain only a component name and its video. */
body.student-view{background:#fff;color:#18222d}
.simple-lesson,.simple-library{width:min(100%,1104px);margin:0 auto;padding:32px 24px}
.simple-lesson h1{font-size:26px;line-height:1.4;font-weight:600;letter-spacing:0;margin:0 0 20px}
.simple-lesson video{width:100%;height:auto;aspect-ratio:16/9;object-fit:contain;background:#0d1520;border-radius:0}
.simple-video-error{margin-top:16px;font-size:14px;color:#475569}
.simple-video-error[hidden]{display:none}
.simple-video-error p{margin:0 0 10px}
.simple-video-error button{border:1px solid #cbd5e1;background:#fff;padding:10px 16px;border-radius:6px}
.simple-library a{display:block;padding:20px 0;font-size:20px;border-bottom:1px solid #e2e8f0}
@media(max-width:600px){.simple-lesson,.simple-library{padding:22px 14px}.simple-lesson h1{font-size:22px;margin-bottom:16px}}