:root { --ink:#18212b; --muted:#6f7d8c; --line:#dfe5e9; --canvas:#f5f7f8; --panel:#fff; --nav:#17222d; --teal:#007f79; --teal-pale:#e1f3f0; --orange:#d96e13; --blue:#2369b1; --red:#c7473c; --shadow:0 10px 28px rgba(27,45,57,.08); }
*{box-sizing:border-box} body{margin:0;background:var(--canvas);font-family:"Noto Sans SC",Arial,sans-serif;color:var(--ink);font-size:14px;line-height:1.45} button,input,select,textarea{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.55} .shell{display:grid;grid-template-columns:216px 1fr;min-height:100vh}.side{background:var(--nav);color:#b7c2cc;padding:18px 12px;display:flex;flex-direction:column;gap:20px}.brand{color:white;padding:8px 12px 17px;border-bottom:1px solid rgba(255,255,255,.12)}.brand b{font-size:18px;display:block}.brand span{font:11px "DM Mono",monospace;color:#8ea1b0;letter-spacing:1px}.role-switch{padding:0 4px}.role-switch label{font-size:11px;color:#8091a0;padding:0 8px;display:block;margin-bottom:7px}.role-list{display:grid;gap:3px}.role{appearance:none;border:0;background:transparent;color:#b7c2cc;text-align:left;padding:8px;border-radius:4px;font-size:13px}.role.active,.role:hover{background:#29414e;color:#fff}.nav{display:grid;gap:3px}.nav button{background:transparent;border:0;color:#b7c2cc;text-align:left;padding:10px 12px;border-radius:4px}.nav button.active,.nav button:hover{background:rgba(255,255,255,.1);color:white}.nav svg,.tool svg{width:17px;height:17px;vertical-align:-3px;margin-right:8px}.side-foot{margin-top:auto;padding:12px;color:#8293a1;font-size:11px;border-top:1px solid rgba(255,255,255,.12)}.main{min-width:0}.topbar{height:64px;background:white;border-bottom:1px solid var(--line);display:flex;align-items:center;padding:0 26px;gap:16px}.crumb{font-size:13px;color:var(--muted)}.crumb b{color:var(--ink)}.spacer{flex:1}.status{font-size:12px;color:var(--teal);background:var(--teal-pale);padding:4px 8px;border-radius:3px}.avatar{width:30px;height:30px;background:#d8e6f0;color:#23536d;display:grid;place-items:center;border-radius:50%;font-weight:700}.page{padding:24px 26px 36px;max-width:1640px;margin:auto}.page-head{display:flex;align-items:flex-start;gap:16px;margin-bottom:18px}.page-head h1{margin:0;font-size:22px;letter-spacing:0}.page-head p{margin:4px 0 0;color:var(--muted);font-size:13px}.actions{margin-left:auto;display:flex;gap:8px;align-items:center}.btn{border:1px solid var(--line);background:#fff;color:var(--ink);padding:8px 11px;border-radius:4px;font-size:13px}.btn:hover{border-color:#96a7b1;background:#fbfcfc}.btn.primary{background:var(--teal);border-color:var(--teal);color:white}.btn.primary:hover{background:#006e69}.btn.danger{color:var(--red)}.workspace{display:grid;grid-template-columns:240px minmax(280px, .84fr) minmax(420px,1.35fr);border:1px solid var(--line);background:var(--panel);min-height:650px}.pane{min-width:0;border-right:1px solid var(--line)}.pane:last-child{border:0}.pane-head{padding:14px 16px;border-bottom:1px solid var(--line);display:flex;align-items:center;gap:8px}.pane-head b{font-size:14px}.pane-head span{font-size:12px;color:var(--muted)}.tiny-btn{border:1px solid var(--line);background:#fff;border-radius:3px;width:27px;height:27px;font-size:17px;line-height:1}.tiny-btn:hover{border-color:var(--teal);color:var(--teal)}.tree{padding:8px}.tree-course{border:0;background:transparent;width:100%;display:block;text-align:left;padding:9px 8px;border-radius:4px;color:#354657}.tree-course.active{background:var(--teal-pale);color:#006c67;font-weight:600}.tree-course small{display:block;color:var(--muted);font-weight:400;margin-top:2px}.tree-empty{padding:15px 9px;color:var(--muted);font-size:12px}.lesson-list{padding:7px}.lesson{border:0;background:transparent;width:100%;display:flex;gap:10px;text-align:left;padding:10px 9px;border-radius:4px;color:var(--ink)}.lesson:hover{background:#f2f6f6}.lesson.active{background:#edf6f5}.lesson-no{font:12px "DM Mono",monospace;color:var(--muted);padding-top:1px;width:20px}.lesson-main{min-width:0;flex:1}.lesson-title{white-space:nowrap;overflow:hidden;text-overflow:ellipsis;font-size:13px}.lesson-meta{display:flex;gap:7px;margin-top:3px;font-size:11px;color:var(--muted)}.dot{width:6px;height:6px;border-radius:50%;background:#d3dce1;margin-top:6px}.dot.done{background:#48a28d}.editor{display:flex;flex-direction:column}.editor-top{padding:16px 18px 0;border-bottom:1px solid var(--line)}.editor-title-row{display:flex;gap:10px;align-items:center}.editor-title{border:0;border-bottom:1px solid transparent;font-size:17px;font-weight:600;padding:3px 0;flex:1;min-width:0}.editor-title:focus{outline:none;border-color:var(--teal)}.label-status{font-size:11px;border:1px solid #b8d7cf;color:#00746d;background:#f1faf8;padding:3px 6px;border-radius:3px;white-space:nowrap}.tabs{display:flex;gap:18px;margin-top:15px;overflow:auto}.tabs button{background:transparent;border:0;color:var(--muted);padding:10px 0 9px;border-bottom:2px solid transparent;white-space:nowrap;font-size:13px}.tabs button.active{color:var(--teal);border-color:var(--teal);font-weight:600}.editor-body{padding:18px;overflow:auto}.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:13px}.field{display:grid;gap:6px}.field.full{grid-column:1 / -1}.field label{font-size:12px;color:#52616e}.field input,.field textarea,.field select{border:1px solid var(--line);border-radius:3px;padding:8px 9px;color:var(--ink);background:white}.field textarea{resize:vertical;min-height:86px}.field input:focus,.field textarea:focus,.field select:focus{outline:2px solid #c9e7e3;border-color:var(--teal)}.form-foot{display:flex;justify-content:flex-end;gap:8px;margin-top:14px}.upload-zone{border:1px dashed #9db3bb;background:#f8fbfb;padding:18px;text-align:center;color:#536976;margin-bottom:14px}.upload-zone b{display:block;color:var(--ink);font-size:13px;margin-bottom:3px}.type-row{display:flex;gap:7px;flex-wrap:wrap;margin-top:11px;justify-content:center}.type-btn{border:1px solid var(--line);background:white;border-radius:3px;padding:5px 8px;color:#53616d;font-size:12px}.type-btn.active{border-color:var(--teal);background:var(--teal-pale);color:#006d66}.resource-table{width:100%;border-collapse:collapse;font-size:13px}.resource-table th{color:#748290;text-align:left;font-size:11px;font-weight:500;padding:8px;border-bottom:1px solid var(--line)}.resource-table td{padding:10px 8px;border-bottom:1px solid #edf0f2}.resource-name{font-weight:500}.resource-note{color:var(--muted);font-size:11px;margin-top:2px}.badge{font-size:11px;border-radius:3px;padding:3px 6px;background:#edf2f5;color:#536473}.badge.video{background:#e9f0fb;color:#2860a1}.badge.ppt{background:#fff0e3;color:#a95411}.badge.pdf{background:#fceceb;color:#a1433b}.badge.animation{background:#f4edfb;color:#7252a4}.icon-btn{background:transparent;border:0;color:#526170;padding:5px}.icon-btn:hover{color:var(--teal)}.empty{padding:25px 4px;color:var(--muted);font-size:13px;text-align:center}.modal-backdrop{position:fixed;inset:0;background:rgba(18,31,40,.55);z-index:20;display:grid;place-items:center;padding:24px}.modal{width:min(980px,100%);height:min(720px,100%);background:white;display:flex;flex-direction:column;box-shadow:var(--shadow)}.modal-head{height:54px;border-bottom:1px solid var(--line);padding:0 16px;display:flex;align-items:center;gap:12px}.modal-head b{font-size:14px}.modal-head span{font-size:12px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.modal-head .icon-btn{margin-left:auto;font-size:20px}.modal-body{min-height:0;flex:1;background:#eef1f3;display:grid;place-items:center}.modal-body iframe,.modal-body video{border:0;width:100%;height:100%;background:#101820}.preview-unavailable{text-align:center;color:#52616e;padding:30px}.preview-unavailable .btn{display:inline-block;margin-top:12px;text-decoration:none}.toast{position:fixed;right:24px;bottom:24px;background:#1d2b34;color:white;padding:10px 14px;border-radius:4px;box-shadow:var(--shadow);z-index:30;font-size:13px}.loading{display:grid;place-items:center;min-height:100vh;color:var(--muted)}.setup{max-width:500px;padding:20px}.setup h2{margin-top:0}.teacher-grid{display:grid;grid-template-columns:minmax(0,1.45fr) minmax(280px,.75fr);gap:18px}.teaching-stage{background:#101c27;color:white;min-height:510px;border:1px solid #243747;display:flex;flex-direction:column}.stage-head{padding:12px 15px;border-bottom:1px solid #2d4657;display:flex;align-items:center;gap:9px}.stage-body{flex:1;display:grid;place-items:center;color:#9fafbb;padding:20px;text-align:center}.stage-body .btn{color:white;background:#203748;border-color:#416072;margin-top:10px}.stage-controls{padding:11px 15px;border-top:1px solid #2d4657;display:flex;gap:8px;align-items:center}.stage-controls .btn{font-size:12px;background:#203748;border-color:#416072;color:white}.info-panel{background:white;border:1px solid var(--line)}.info-block{padding:15px;border-bottom:1px solid var(--line)}.info-block:last-child{border:0}.info-block h3{font-size:13px;margin:0 0 8px}.info-block p{color:#556674;font-size:13px;margin:0;white-space:pre-line}.resource-call{display:flex;width:100%;gap:9px;text-align:left;padding:8px 0;background:transparent;border:0;border-bottom:1px solid #edf0f2}.resource-call:last-child{border-bottom:0}.resource-call:hover{color:var(--teal)}.role-message{background:#fff;border:1px solid var(--line);padding:24px;min-height:300px}.role-message h2{margin:0 0 8px;font-size:18px}.role-message p{color:var(--muted);margin:0 0 18px}.kpis{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;background:var(--line);border:1px solid var(--line)}.kpi{background:white;padding:17px}.kpi b{display:block;font:24px "DM Mono",monospace;color:var(--ink)}.kpi span{font-size:12px;color:var(--muted)}.create-dialog{position:fixed;z-index:25;inset:0;display:grid;place-items:center;background:rgba(18,31,40,.42);padding:20px}.dialog{background:white;width:min(460px,100%);padding:20px;box-shadow:var(--shadow)}.dialog h2{font-size:17px;margin:0 0 4px}.dialog p{font-size:13px;color:var(--muted);margin:0 0 18px}.dialog .field{margin-bottom:12px}.dialog-foot{display:flex;justify-content:flex-end;gap:8px;margin-top:18px}@media(max-width:1060px){.workspace{grid-template-columns:215px minmax(270px,.9fr) minmax(360px,1.2fr)}.page{padding:18px}.topbar{padding:0 18px}}@media(max-width:820px){.shell{grid-template-columns:1fr}.side{display:none}.topbar{height:54px}.page{padding:14px}.workspace{display:block}.pane{border-right:0;border-bottom:1px solid var(--line)}.pane:first-child{max-height:170px;overflow:auto}.pane:nth-child(2){max-height:260px;overflow:auto}.page-head{flex-wrap:wrap}.actions{margin-left:0;width:100%}.teacher-grid{grid-template-columns:1fr}.teaching-stage{min-height:400px}.form-grid{grid-template-columns:1fr}.modal-backdrop{padding:0}.modal{width:100%;height:100%}}