:root{--primary: #2563eb;--primary-dark: #1d4ed8;--bg: #f5f7fa;--card: #ffffff;--text: #1f2937;--muted: #6b7280;--border: #e5e7eb;--danger: #dc2626;--success: #16a34a;--shadow: 0 1px 3px rgba(0, 0, 0, .08), 0 1px 2px rgba(0, 0, 0, .04)}*{box-sizing:border-box}html,body{margin:0;padding:0;height:100%;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;background:var(--bg);color:var(--text)}#app{min-height:100%}button{font-family:inherit;cursor:pointer;border:none;border-radius:8px;padding:8px 14px;font-size:14px;background:var(--primary);color:#fff;transition:background .15s,opacity .15s}button:hover{background:var(--primary-dark)}button:disabled{opacity:.5;cursor:not-allowed}button.ghost{background:#fff;color:var(--text);border:1px solid var(--border)}button.ghost:hover{background:#f3f4f6}button.danger{background:var(--danger)}button.danger:hover{background:#b91c1c}input,select{font-family:inherit;font-size:14px;padding:8px 10px;border:1px solid var(--border);border-radius:8px;outline:none;background:#fff}input:focus,select:focus{border-color:var(--primary)}.topbar{display:flex;align-items:center;justify-content:space-between;padding:14px 24px;background:var(--card);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:10}.topbar h1{font-size:18px;margin:0;display:flex;align-items:center;gap:8px}.topbar .links{display:flex;gap:10px;align-items:center}.container{max-width:1040px;margin:0 auto;padding:24px}.muted{color:var(--muted);font-size:13px}.section-title{font-size:16px;font-weight:600;margin:24px 0 12px}.login-wrap{min-height:100vh;display:flex;align-items:center;justify-content:center;background:linear-gradient(135deg,#eef2ff,#f5f7fa)}.login-card{background:var(--card);padding:32px;border-radius:16px;box-shadow:var(--shadow);width:360px;text-align:center}.login-card h2{margin:0 0 6px}.login-card .hint{color:var(--muted);font-size:13px;margin-bottom:18px}.login-card input{width:100%;margin-bottom:12px;text-align:center}.login-error{color:var(--danger);font-size:13px;min-height:18px;margin-top:4px}.course-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:16px}.course-card{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:16px;box-shadow:var(--shadow)}.course-card .head{display:flex;align-items:center;justify-content:space-between}.course-card .head .name{font-weight:600;font-size:15px}.course-card .head .count{color:var(--muted);font-size:12px}.course-card .actions{display:flex;gap:8px;margin-top:12px;flex-wrap:wrap}.file-list{margin-top:12px;border-top:1px dashed var(--border);padding-top:10px;display:flex;flex-direction:column;gap:6px}.file-row{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:6px 8px;border-radius:8px;background:#f9fafb}.file-row .fname{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:13px}.file-row .meta{color:var(--muted);font-size:12px;margin-right:8px}.file-row .ops{display:flex;gap:6px}.file-row .ops button{padding:5px 10px;font-size:12px}.empty{color:var(--muted);text-align:center;padding:40px 0}.create-bar{display:flex;gap:8px;margin-bottom:8px}.create-bar input{flex:1}.progress-mask{position:fixed;inset:0;background:#00000059;display:flex;align-items:center;justify-content:center;z-index:50}.progress-box{background:#fff;padding:24px 28px;border-radius:14px;width:320px;text-align:center}.progress-box .bar{height:8px;background:#e5e7eb;border-radius:4px;overflow:hidden;margin-top:12px}.progress-box .bar>div{height:100%;background:var(--primary);width:0%;transition:width .2s}.teacher-list{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:16px}.teacher-course{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:16px;box-shadow:var(--shadow)}.teacher-course h3{margin:0 0 10px;font-size:15px}.teacher-file{display:flex;align-items:center;justify-content:space-between;padding:10px 12px;border-radius:10px;background:#f9fafb;margin-bottom:8px}.teacher-file .tname{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.teacher-file .play-btn{background:var(--success)}.teacher-file .play-btn:hover{background:#15803d}.player{position:fixed;inset:0;background:#000;z-index:100;display:flex;flex-direction:column;overflow:hidden}.player .topbar-player{position:absolute;top:0;left:0;right:0;z-index:5;display:flex;align-items:center;justify-content:space-between;padding:10px 16px;color:#fff;background:linear-gradient(to bottom,#0009,#0000);opacity:0;pointer-events:none;transition:opacity .25s}.player.topbar-on .topbar-player{opacity:1;pointer-events:auto}.player .topbar-player .title{font-size:14px;opacity:.9}.player .topbar-player .ctrls{display:flex;gap:8px}.player .topbar-player .ctrls button{padding:6px 10px;font-size:13px;background:#ffffff26}.player .topbar-player .ctrls button:hover{background:#ffffff4d}.player .topbar-player .ctrls button.active{background:var(--primary)}.player .stage{flex:1;display:flex;align-items:center;justify-content:center;position:relative;cursor:none;-webkit-user-select:none;user-select:none}.player.drawing .stage{cursor:crosshair}.player .stage img{display:block;pointer-events:none;-webkit-user-drag:none}.player .arrow{position:absolute;top:50%;transform:translateY(-50%);background:#2d2d2da6;color:#fff;border:none;width:64px;height:64px;border-radius:50%;font-size:30px;z-index:4;opacity:0;pointer-events:none;transition:opacity .25s,background .15s}.player.arrows-on .arrow{opacity:1;pointer-events:auto}.player .arrow:hover{background:#ffffff4d}.player .arrow.prev{left:16px}.player .arrow.next{right:16px}.player .page-indicator{position:absolute;bottom:14px;left:50%;transform:translate(-50%);color:#fff;background:#00000080;padding:4px 14px;border-radius:20px;font-size:13px;z-index:5}.player .thumbs{position:absolute;left:0;right:0;bottom:0;z-index:6;display:flex;gap:8px;padding:10px;overflow-x:auto;background:#000000a6;transform:translateY(100%);transition:transform .25s}.player .thumbs.show{transform:translateY(0)}.player .thumbs{cursor:grab}.player .thumbs.dragging{cursor:grabbing}.player .thumbs.dragging img{pointer-events:none}.player .thumbs img{display:block;height:84px;width:120px;object-fit:contain;background:#1c1c1c;border-radius:6px;flex:none;-webkit-user-select:none;user-select:none;-webkit-user-drag:none}.player .thumbs .thumb-wrap{position:relative;flex:none;line-height:0;border:2px solid transparent;border-radius:6px;overflow:hidden;cursor:pointer;opacity:.6;transition:opacity .15s}.player .thumbs .thumb-wrap.active{opacity:1;border-color:var(--primary)}.player .thumbs.dragging .thumb-wrap{pointer-events:none}.player .thumbs .thumb-num{position:absolute;left:4px;bottom:4px;background:#0000009e;color:#fff;font-size:11px;padding:1px 6px;border-radius:8px;line-height:1.4;pointer-events:none}.player .laser{position:absolute;width:16px;height:16px;border-radius:50%;background:radial-gradient(circle,#ff3b3b,red 40%,#f000 70%);pointer-events:none;transform:translate(-50%,-50%);opacity:0;z-index:7;box-shadow:0 0 12px 4px #ff0000b3}.player .laser.active{opacity:1}.player.hide-ui .page-indicator{opacity:0;pointer-events:none}.player.hide-ui:hover .page-indicator{opacity:1;pointer-events:auto}.player.black{background:#000}.player.black .stage,.player.black .thumbs{display:none}.speed-select{background:#ffffff26;color:#fff;border:none}.speed-select option{color:#000}.player #anno{position:absolute;left:0;top:0;width:100%;height:100%;z-index:3;pointer-events:none;touch-action:none}.player.drawing #anno{pointer-events:auto;cursor:crosshair}.player .annotate{position:absolute;left:12px;top:70px;z-index:8;display:flex;flex-direction:column;gap:6px;background:#141414d9;padding:6px;border-radius:12px;box-shadow:0 4px 18px #00000073;-webkit-user-select:none;user-select:none;width:min-content}.player .annotate .anno-header{display:flex;align-items:center;justify-content:space-between;gap:4px;cursor:grab;padding:0 0 4px;border-bottom:1px solid rgba(255,255,255,.15)}.player .annotate .anno-header:active{cursor:grabbing}.player .annotate .anno-title{font-size:14px;line-height:1;color:#ffffffe6}.player .annotate .anno-header #anno-collapse{width:22px;height:22px;font-size:11px;background:transparent;color:#fff;padding:0;border-radius:6px}.player .annotate .anno-header #anno-collapse:hover{background:#ffffff2e}.player .annotate.collapsed{gap:0;padding-bottom:6px}.player .annotate.collapsed .anno-body{display:none}.player .annotate.collapsed .anno-header{border-bottom:none;padding-bottom:0}.player .annotate .anno-body{display:flex;flex-direction:column;gap:6px}.player .anno-row{display:flex;flex-direction:column;gap:5px;align-items:center}.player .anno-row+.anno-row{border-top:1px solid rgba(255,255,255,.15);padding-top:7px}.player .anno-row button{width:34px;height:34px;border-radius:8px;font-size:15px;background:transparent;color:#fff;padding:0;display:flex;align-items:center;justify-content:center}.player .anno-row button:hover{background:#ffffff2e}.player .anno-row button.active{background:var(--primary)}.player .anno-row button i{border-radius:50%;background:#fff;display:block}.player .swatch{width:22px!important;height:22px!important;border-radius:50%!important;border:2px solid rgba(255,255,255,.6)}.player .swatch.active{outline:2px solid #fff;outline-offset:1px}.player .custom-swatch{position:relative;width:22px;height:22px;font-size:13px;cursor:pointer;display:flex;align-items:center;justify-content:center;border-radius:50%;background:#ffffff26}.player .custom-swatch input{position:absolute;inset:0;opacity:0;cursor:pointer}.player.black #anno,.player.black .annotate{display:none}.player .annotate.docked{opacity:0;transition:left .22s ease,opacity .25s ease}.player .annotate.docked.peek{opacity:1}.player .anno-text-input{position:absolute;z-index:9;background:#ffffff1f;border:1px dashed rgba(255,255,255,.75);border-radius:4px;padding:2px 6px;outline:none;min-width:140px;font-family:inherit;line-height:1.25}.player .anno-text-input::placeholder{color:#ffffff73}.player.hide-ui .annotate{opacity:1;pointer-events:auto}.upload-queue{position:fixed;right:18px;bottom:18px;z-index:60;width:340px;background:#fff;border-radius:14px;box-shadow:0 8px 30px #00000040;overflow:hidden;font-size:13px}.upload-queue .uq-head{display:flex;align-items:center;justify-content:space-between;padding:10px 14px;background:var(--primary);color:#fff;font-weight:600}.upload-queue .uq-close{background:transparent;color:#fff;padding:2px 8px;font-size:13px}.upload-queue .uq-close:hover{background:#fff3}.upload-queue .uq-list{max-height:320px;overflow-y:auto;padding:8px;display:flex;flex-direction:column;gap:8px}.upload-queue .uq-item{padding:8px 10px;border-radius:8px;background:#f9fafb}.upload-queue .uq-item.active{background:#eef2ff}.upload-queue .uq-item.done .uq-status{color:var(--success)}.upload-queue .uq-item.error .uq-status{color:var(--danger)}.upload-queue .uq-name{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-weight:500}.upload-queue .uq-status{display:block;color:var(--muted);margin:4px 0;font-size:12px}.upload-queue .uq-bar{height:6px;background:#e5e7eb;border-radius:3px;overflow:hidden}.upload-queue .uq-bar>div{height:100%;width:0%;background:var(--primary);transition:width .2s}.upload-queue.done{cursor:pointer}.tabs{display:flex;gap:8px;padding:16px 24px 0;flex-wrap:wrap}.tab{background:transparent;color:var(--muted);border:1px solid var(--border);padding:8px 18px;font-size:14px}.tab:hover{background:#fff;color:var(--text)}.tab.active{background:var(--primary);color:#fff;border-color:var(--primary)}.tab-body{padding:18px 24px 40px}.role-badge{display:inline-block;padding:4px 12px;border-radius:999px;background:#eef2ff;color:var(--primary);font-size:13px;font-weight:600;margin-right:8px}.grant-bar{display:flex;align-items:center;gap:10px;margin:14px 0}.grant-bar select{padding:8px 12px;border-radius:8px;border:1px solid var(--border);font-size:14px;min-width:220px}.grant-box{margin-top:8px}.grant-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:10px;margin-top:12px}.grant-item{display:flex;align-items:center;gap:8px;padding:10px 14px;border:1px solid var(--border);border-radius:10px;background:#fff;cursor:pointer;font-size:14px}.grant-item:hover{border-color:var(--primary)}.grant-item input{width:16px;height:16px}.account-form{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin-bottom:18px}.account-form input,.account-form select{padding:8px 12px;border-radius:8px;border:1px solid var(--border);font-size:14px}.account-form input{min-width:160px}.acc-tbl{width:100%;border-collapse:collapse;background:#fff;border-radius:10px;overflow:hidden;box-shadow:var(--shadow)}.acc-tbl th,.acc-tbl td{text-align:left;padding:12px 14px;border-bottom:1px solid var(--border);font-size:14px}.acc-tbl th{background:#f9fafb;color:var(--muted);font-weight:600}.acc-tbl tr:last-child td{border-bottom:none}.acc-ops{display:flex;gap:8px}.role-sel{padding:6px 8px;border-radius:8px;border:1px solid var(--border);font-size:13px}.tag-on{color:var(--success);font-weight:600}.tag-off{color:var(--danger);font-weight:600}