*{box-sizing:border-box}
  .frame{width:min(96vw,1600px);height:min(92vh,1100px);min-width:600px;min-height:420px;border-radius:18px;overflow:hidden;box-shadow:0 20px 60px rgba(13,27,46,.22);position:relative}
  .wb-header{position:absolute;top:0;left:0;right:0;display:flex;align-items:center;padding:16px 22px;border-bottom:1px solid #EBEAE5;background:#FFFFFF;gap:12px;transition:opacity .25s,transform .25s;z-index:20}
  .wb-header.hidden{opacity:0;transform:translateY(-8px);pointer-events:none}
  .wb-header-title{font-family:'DM Serif Display',Georgia,serif;font-size:17px;color:#1A1A18}
  .wb-header-sub{font-size:11px;color:#8391A8}
  .coord-readout{font-size:9.5px;color:#B8BEC9;font-family:'Courier New',monospace;margin-left:auto}

  .chip-trail{display:flex;align-items:center;gap:5px;margin-left:auto}
  .page-chip{min-width:20px;height:20px;padding:0 6px;border-radius:10px;background:#F0EFE9;color:#8B8A84;font-size:10px;font-weight:700;display:flex;align-items:center;justify-content:center;cursor:pointer;transition:all .15s}
  .page-chip:hover{background:rgba(255,255,255,.18);color:#fff;transform:scale(1.08)}
  .page-chip.current{background:#2BA08A;color:#fff;min-width:24px;height:24px;font-size:11px}

  .newpage-toast{position:absolute;top:60px;left:50%;transform:translateX(-50%) translateY(-8px);background:#0D1B2E;color:#fff;font-size:11.5px;font-weight:600;padding:8px 8px 8px 14px;border-radius:20px;opacity:0;transition:all .25s cubic-bezier(.34,1.4,.64,1);z-index:25;display:flex;align-items:center;gap:8px;pointer-events:none}
  .comment-marker{position:absolute;width:24px;height:24px;border-radius:50%;background:#2BA08A;color:#fff;display:flex;align-items:center;justify-content:center;font-size:13px;cursor:pointer;pointer-events:auto;box-shadow:0 2px 6px rgba(13,27,46,.3);border:2px solid #fff;transition:transform .12s}
  .comment-marker:hover{transform:scale(1.15)}
  .comment-popover{display:none;position:absolute;z-index:22;background:rgba(255,255,255,.94);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-radius:12px;padding:10px;box-shadow:0 16px 40px rgba(13,27,46,.25);border:1px solid rgba(13,27,46,.06);width:220px}
  .comment-popover.show{display:block}
  .comment-popover textarea{width:100%;border:1px solid #E5E7EB;border-radius:8px;padding:8px;font-size:12.5px;font-family:inherit;resize:none;box-sizing:border-box}
  .comment-popover-actions{display:flex;justify-content:space-between;align-items:center;margin-top:8px}
  .comment-save-btn{background:#2BA08A;color:#fff;border:none;border-radius:7px;padding:6px 14px;font-size:12px;font-weight:600;cursor:pointer}
  .comment-delete-btn{background:none;border:none;color:#DC2626;cursor:pointer;width:28px;height:28px;border-radius:7px;display:flex;align-items:center;justify-content:center}
  .comment-delete-btn:hover{background:#FEF2F2}
  .shortcuts-backdrop{position:absolute;inset:0;background:rgba(13,27,46,.45);z-index:40;display:flex;align-items:center;justify-content:center;opacity:0;pointer-events:none;transition:opacity .18s ease}
  .shortcuts-backdrop.show{opacity:1;pointer-events:auto}
  .shortcuts-card{background:#0D1B2E;border-radius:18px;padding:22px 24px;width:340px;max-height:80%;overflow-y:auto;box-shadow:0 24px 60px rgba(0,0,0,.4);transform:scale(.94) translateY(8px);transition:transform .18s ease}
  .shortcuts-backdrop.show .shortcuts-card{transform:scale(1) translateY(0)}
  .shortcuts-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px}
  .shortcuts-title{font-family:'DM Serif Display',Georgia,serif;font-size:18px;color:#fff}
  .shortcuts-section-label{font-size:10.5px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:#5C7089;margin:16px 0 8px}
  .shortcuts-section-label:first-of-type{margin-top:0}
  .shortcuts-row{display:flex;align-items:center;justify-content:space-between;padding:7px 0;font-size:13px;color:#D5DCE8}
  .key-cap{background:rgba(255,255,255,.1);border:1px solid rgba(255,255,255,.14);border-radius:6px;padding:3px 9px;font-size:11px;font-weight:600;color:#fff;font-family:inherit;white-space:nowrap}
  .newpage-toast.show{opacity:1;transform:translateX(-50%) translateY(0);pointer-events:auto}
  .viewprev-btn{background:rgba(255,255,255,.15);border:none;color:#fff;font-size:11px;font-weight:600;padding:5px 10px;border-radius:14px;cursor:pointer;white-space:nowrap;transition:background .15s}
  .viewprev-btn:hover{background:rgba(255,255,255,.24)}
  .icon-btn{width:36px;height:36px;border-radius:10px;border:none;background:#F5F4EF;color:#6B6A64;display:flex;align-items:center;justify-content:center;cursor:pointer;transition:background .15s,transform .1s}
  .icon-btn:hover{background:rgba(255,255,255,.14)}
  .icon-btn:active,.icon-btn.pressed{transform:scale(.94)}
  .wb-header-more-menu{display:none;position:absolute;top:44px;right:0;background:#fff;border-radius:12px;padding:6px;box-shadow:0 16px 40px rgba(13,27,46,.18);border:1px solid #EBEAE5;z-index:22;min-width:190px;flex-direction:column;gap:1px}
  .wb-header-more-menu.show{display:flex}
  .wb-header-more-item{display:flex;align-items:center;gap:10px;background:none;border:none;color:#3A3934;padding:9px 10px;border-radius:8px;font-size:12.5px;cursor:pointer;text-align:left;white-space:nowrap}
  .wb-header-more-item:hover{background:#F5F4EF}
  .notes-count-badge{margin-left:auto;background:#2BA08A;color:#fff;font-size:10px;font-weight:700;border-radius:9px;padding:1px 6px;min-width:16px;text-align:center}
  .notes-panel-backdrop{display:none;position:absolute;inset:0;background:rgba(13,27,46,.3);z-index:30;align-items:center;justify-content:center}
  .notes-panel-backdrop.show{display:flex}
  .notes-panel{background:#fff;border-radius:16px;width:380px;max-height:70%;display:flex;flex-direction:column;box-shadow:0 24px 60px rgba(13,27,46,.3)}
  .notes-panel-hdr{display:flex;align-items:center;justify-content:space-between;padding:16px 18px;border-bottom:1px solid #EBEAE5;font-family:'DM Serif Display',Georgia,serif;font-size:16px;color:#1A1A18}
  .notes-panel-close{width:26px;height:26px;border-radius:50%;border:none;background:#F5F4EF;color:#6B6A64;cursor:pointer;display:flex;align-items:center;justify-content:center}
  .notes-panel-empty{padding:32px 18px;text-align:center;color:#B8B7B0;font-size:12.5px}
  .notes-panel-list{overflow-y:auto;padding:10px}
  .notes-row{display:flex;gap:10px;align-items:flex-start;padding:9px 8px;border-radius:10px;cursor:pointer}
  .notes-row:hover{background:#F5F4EF}
  .notes-row-thumb{width:52px;height:34px;border-radius:5px;object-fit:cover;border:1px solid rgba(0,0,0,.1);flex-shrink:0;background:#FDFBF7;margin-top:1px}
  .notes-row-text{font-size:12.5px;color:#3A3934;line-height:1.4;margin-bottom:3px}
  .notes-row-meta{font-size:10.5px;color:#B8B7B0}
  .icon-btn.focus-on{background:#0D1B2E;color:#fff}

  .canvas-wrap{position:absolute;inset:0;overflow:hidden;background-color:#FDFBF7;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='200' height='200'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.12'/%3E%3C/svg%3E");touch-action:none;-webkit-user-select:none;user-select:none;-webkit-touch-callout:none}
  #wb{width:100%;height:100%;display:block;touch-action:none;position:relative;z-index:1}
  #wb.draw-mode{cursor:crosshair}
  #wb.pan-mode{cursor:grab}
  #wb.pan-mode.grabbing{cursor:grabbing}
  #bgLayer{position:absolute;inset:0;pointer-events:none;z-index:0}
  .empty-page-hint{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);pointer-events:none;z-index:0;font-size:14px;color:#B8BEC9;font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;opacity:1;transition:opacity .3s ease;white-space:nowrap}
  .empty-page-hint.hidden{opacity:0}

  .tray{position:absolute;top:50%;right:20px;transform:translateY(-50%);background:#FFFFFF;backdrop-filter:blur(10px);border-radius:22px;padding:14px 10px;box-shadow:0 4px 16px rgba(20,20,18,.14);display:flex;flex-direction:column;align-items:center;gap:8px;border:1px solid #DEDCD3;z-index:15;transition:opacity .25s,transform .25s}
  .tray.hidden{opacity:0;transform:translateY(calc(-50% + 12px));pointer-events:none}
  .tray-icon{width:36px;height:36px;border-radius:50%;border:none;background:none;color:#6B6A64;display:flex;align-items:center;justify-content:center;cursor:pointer;font-size:16px;transition:background .15s,transform .1s,color .15s}
  @keyframes syncSpin{from{transform:rotate(0deg)}to{transform:rotate(360deg)}}
  #syncIcon.spinning{animation:syncSpin 0.9s linear infinite}
  #studentDrawToggle.on{background:#2BA08A;color:#fff}
  .tray-icon:hover{background:rgba(255,255,255,.08)}
  .tray-icon:active,.tray-icon.pressed{transform:scale(.92)}
  .tray-icon.active{background:#0D1B2E;color:#fff}
  .tray-icon:disabled{opacity:.3;cursor:default;pointer-events:none}
  .tray-color-dot{width:22px;height:22px;border-radius:50%;box-shadow:0 0 0 2px rgba(255,255,255,.55)}
  .tray-div{width:22px;height:1px;background:rgba(255,255,255,.14)}
  .wb-header-div{width:1px;height:20px;background:rgba(255,255,255,.14);margin:0 2px}

  .insert-menu{display:block;opacity:0;pointer-events:none;transform:scale(.96) translateY(-4px);transition:opacity .16s ease,transform .16s ease;position:absolute;top:44px;left:0;z-index:20;background:rgba(255,255,255,.72);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-radius:12px;padding:6px;box-shadow:0 16px 40px rgba(13,27,46,.22);border:1px solid rgba(13,27,46,.06);width:140px}
  .insert-menu.show{opacity:1;pointer-events:auto;transform:scale(1) translateY(0)}
  .insert-opt{display:flex;align-items:center;gap:9px;padding:8px 10px;border-radius:8px;cursor:pointer;font-size:12px;color:#0D1B2E;transition:background .15s}
  .insert-opt:hover{background:#F8F9FC}
  .insert-opt:active{transform:scale(.97)}
  .insert-opt i{font-size:15px;color:#6B7280}

  .shape-picker{display:flex;flex-wrap:wrap;max-width:180px;opacity:0;pointer-events:none;transform:translateY(-50%) scale(.96);transition:opacity .16s ease,transform .16s ease;position:absolute;background:rgba(255,255,255,.72);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-radius:14px;padding:8px;box-shadow:0 16px 40px rgba(13,27,46,.22);border:1px solid rgba(13,27,46,.06);gap:4px;z-index:16}

  .size-hdr{font-size:9.5px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:#9CA3AF;margin-bottom:8px}
  .size-row{display:flex;align-items:flex-end;justify-content:space-between;gap:4px}

  .pentype-row{display:flex;gap:6px}
  .pentype-opt{flex:1;display:flex;flex-direction:column;align-items:center;gap:5px;padding:7px 2px;border-radius:9px;cursor:pointer;border:1.5px solid #E5E7EB;transition:border-color .15s,background .15s,transform .1s}
  .pentype-opt:hover{background:#F8F9FC}
  .pentype-opt:active{transform:scale(.95)}
  .pentype-opt.sel{border-color:#2BA08A;background:#F0F9F6}
  .pentype-opt i{font-size:15px;color:#6B7280}
  .pentype-opt.sel i{color:#2BA08A}
  .pentype-opt-label{font-size:8.5px;color:#9CA3AF}
  .pentype-opt.sel .pentype-opt-label{color:#0D1B2E;font-weight:600}
  .size-opt{display:flex;flex-direction:column;align-items:center;gap:6px;cursor:pointer;flex:1;padding:2px 0;border-radius:8px;transition:background .15s}
  .size-opt:hover{background:#F8F9FC}
  .size-opt:active{transform:scale(.95)}
  .size-dot-wrap{width:30px;height:30px;display:flex;align-items:center;justify-content:center;border-radius:50%;transition:background .15s}
  .size-opt.sel .size-dot-wrap{background:#EEF1F6;box-shadow:0 0 0 1.5px #0D1B2E}
  .size-dot{border-radius:50%;background:#0D1B2E}
  .size-opt-label{font-size:8.5px;color:#9CA3AF}
  .size-opt.sel .size-opt-label{color:#0D1B2E;font-weight:600}

  .size-sheet{display:block;opacity:0;pointer-events:none;transform:translateY(-50%) scale(.96);transition:opacity .16s ease,transform .16s ease;position:absolute;z-index:16;background:rgba(255,255,255,.72);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-radius:16px;padding:14px;width:230px;box-shadow:0 16px 40px rgba(13,27,46,.22);border:1px solid rgba(13,27,46,.06)}
  .size-sheet.show{opacity:1;pointer-events:auto;transform:translateY(-50%) scale(1)}
  .shape-picker.show{opacity:1;pointer-events:auto;transform:translateY(-50%) scale(1)}
  .shape-opt{width:38px;height:38px;border-radius:8px;border:none;background:none;color:#6B7280;display:flex;align-items:center;justify-content:center;cursor:pointer;font-size:17px;transition:background .15s,transform .1s}
  .shape-opt:hover{background:#F1F3F7}
  .shape-opt:active{transform:scale(.92)}
  .shape-opt.active{background:#EEF1F6;color:#2BA08A}

  #wb-color-sheet{display:block;opacity:0;pointer-events:none;transform:translateY(-50%) scale(.96);transition:opacity .16s ease,transform .16s ease;position:absolute;z-index:16;background:rgba(255,255,255,.72);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-radius:16px;padding:14px;width:290px;box-shadow:0 16px 40px rgba(13,27,46,.22);border:1px solid rgba(13,27,46,.06)}
  #wb-color-sheet.show{opacity:1;pointer-events:auto;transform:translateY(-50%) scale(1)}
  .wb-dock-swatch{width:14px;height:14px;border-radius:50%;cursor:pointer;border:none;padding:0;transition:transform .15s cubic-bezier(.34,1.56,.64,1)}
  .wb-dock-swatch:hover{transform:scale(1.3)}
  .wb-dock-swatch.sel{transform:scale(1.3);box-shadow:0 0 0 2px #fff,0 0 0 3px var(--swatch-c)}

  .bg-picker{display:block;opacity:0;pointer-events:none;transform:scale(.96) translateY(-4px);transition:opacity .16s ease,transform .16s ease;position:absolute;top:52px;right:16px;z-index:20;background:rgba(255,255,255,.72);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-radius:14px;padding:12px;box-shadow:0 16px 40px rgba(13,27,46,.22);border:1px solid rgba(13,27,46,.06);width:280px}

  .templates-panel{display:block;opacity:0;pointer-events:none;transform:scale(.96) translateY(-4px);transition:opacity .16s ease,transform .16s ease;position:absolute;top:52px;right:0;z-index:20;background:rgba(255,255,255,.72);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-radius:14px;padding:12px;box-shadow:0 16px 40px rgba(13,27,46,.22);border:1px solid rgba(13,27,46,.06);width:300px;max-height:400px;overflow-y:auto}
  .templates-panel.show{opacity:1;pointer-events:auto;transform:scale(1) translateY(0)}
  .tpl-save-btn{width:100%;display:flex;align-items:center;justify-content:center;gap:7px;background:#2BA08A;color:#fff;border:none;border-radius:9px;padding:10px;font-size:12px;font-weight:600;cursor:pointer;transition:background .15s,transform .1s;margin-top:2px}
  .tpl-save-btn:hover{background:#259485}
  .tpl-save-btn:active{transform:scale(.98)}
  .tpl-divider{height:1px;background:#F1F3F7;margin:12px 0}
  .tpl-empty{font-size:11.5px;color:#9CA3AF;text-align:center;padding:16px 4px}
  .tpl-row{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:9px 8px;border-radius:9px;cursor:pointer;transition:background .15s}
  .tpl-row:hover{background:#F8F9FC}
  .tpl-row:active{transform:scale(.98)}
  .tpl-info{min-width:0}
  .tpl-name{font-size:12px;font-weight:600;color:#0D1B2E;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
  .tpl-meta{font-size:10px;color:#9CA3AF;margin-top:1px}
  .tpl-delete-btn{width:26px;height:26px;flex-shrink:0;border-radius:7px;border:none;background:none;color:#B8BEC9;display:flex;align-items:center;justify-content:center;cursor:pointer;transition:background .15s,color .15s}
  .tpl-delete-btn:hover{background:#FEF2F2;color:#DC2626}

  .graph-sheet{display:block;opacity:0;pointer-events:none;transform:translateX(-50%) scale(.96) translateY(-4px);transition:opacity .16s ease,transform .16s ease;position:absolute;top:52px;left:50%;z-index:20;background:rgba(255,255,255,.72);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-radius:14px;padding:14px;box-shadow:0 16px 40px rgba(13,27,46,.22);border:1px solid rgba(13,27,46,.06);width:260px}
  .graph-sheet.show{opacity:1;pointer-events:auto;transform:translateX(-50%) scale(1) translateY(0)}
  .graph-input-row{display:flex;align-items:center;gap:8px;background:#F8F9FC;border:1.5px solid #E5E7EB;border-radius:9px;padding:8px 10px;transition:border-color .15s}
  .graph-input-row:focus-within{border-color:#2BA08A}
  .graph-yeq{font-size:13px;color:#6B7280;font-weight:600;font-family:'Courier New',monospace}
  .graph-input-row input{border:none;outline:none;flex:1;font-size:13px;font-family:'Courier New',monospace;color:#0D1B2E;background:none}
  .graph-math-preview{min-height:28px;padding:6px 2px 0;font-family:'DM Serif Display',Georgia,serif;font-size:16px;color:#0D1B2E;letter-spacing:.02em;line-height:1.3}
  .graph-math-preview sup{font-size:.65em;vertical-align:baseline;position:relative;top:-0.5em}
  .graph-math-preview .frac{display:inline-flex;flex-direction:column;align-items:center;vertical-align:middle;font-size:.82em;margin:0 3px;line-height:1.15}
  .graph-math-preview .fnum{padding:0 3px 2px;border-bottom:1.4px solid currentColor}
  .graph-math-preview .fden{padding:2px 3px 0}
  .graph-error{font-size:10.5px;color:#DC2626;margin-top:6px;min-height:14px}
  .graph-plot-btn{width:100%;margin-top:8px;background:#2BA08A;color:#fff;border:none;border-radius:9px;padding:9px;font-size:12px;font-weight:600;cursor:pointer;transition:background .15s,transform .1s}
  .graph-plot-btn:hover{background:#259485}
  .graph-plot-btn:active{transform:scale(.98)}
  .graph-slider-row{display:flex;align-items:center;gap:8px;margin-top:8px}
  .graph-slider-label{font-size:12px;font-weight:700;color:#0D1B2E;font-family:'Courier New',monospace;width:14px}
  .graph-slider-row input[type=range]{flex:1;accent-color:#2BA08A}
  .graph-slider-val{font-size:10.5px;color:#6B7280;font-family:'Courier New',monospace;width:32px;text-align:right}
  .bg-picker.show{opacity:1;pointer-events:auto;transform:scale(1) translateY(0)}
  .bg-hdr{font-size:11px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:#9CA3AF;margin-bottom:10px}
  .bg-grid-opts{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}
  .bg-opt{border-radius:9px;border:1.5px solid #E5E7EB;cursor:pointer;overflow:hidden;transition:border-color .15s,transform .1s}
  .bg-opt:hover{border-color:#B8BEC9}
  .bg-opt:active{transform:scale(.96)}
  .bg-opt.sel{border-color:#2BA08A;box-shadow:0 0 0 2px rgba(43,160,138,.15)}
  .bg-opt-preview{height:40px;background:#FDFBF7}
  .bg-opt-label{font-size:9.5px;color:#6B7280;text-align:center;padding:4px 2px;background:#fff}

  .zoom-ctrl{position:absolute;bottom:16px;left:16px;background:#FFFFFF;backdrop-filter:blur(10px);border-radius:20px;padding:6px 8px;box-shadow:0 4px 16px rgba(20,20,18,.14);display:flex;align-items:center;gap:2px;border:1px solid #DEDCD3;z-index:15;transition:opacity .25s}
  .zoom-ctrl.hidden{opacity:0;pointer-events:none}
  .zoom-btn{width:26px;height:26px;border-radius:50%;border:none;background:none;color:#6B6A64;display:flex;align-items:center;justify-content:center;cursor:pointer;font-size:13px}
  .zoom-btn:hover{background:rgba(255,255,255,.1)}
  .zoom-pct{font-size:11px;color:#3A3934;font-weight:600;width:42px;text-align:center;cursor:pointer}

  .recenter-btn{position:absolute;bottom:16px;right:16px;background:#0D1B2E;color:#fff;border:none;border-radius:20px;padding:9px 15px;font-size:11.5px;font-weight:600;cursor:pointer;display:flex;align-items:center;gap:6px;box-shadow:0 6px 16px rgba(13,27,46,.25);z-index:15;opacity:0;pointer-events:none;transition:opacity .2s}
  .recenter-btn.show{opacity:1;pointer-events:auto}

  .hold-ring{display:none;position:absolute;width:44px;height:44px;border-radius:50%;pointer-events:none;z-index:12}

  .selection-bar{display:none;position:absolute;transform:translate(-50%,-100%);background:#0D1B2E;border-radius:12px;padding:5px;box-shadow:0 10px 24px rgba(13,27,46,.28);z-index:14;align-items:center;gap:3px}
  .selection-bar.show{display:flex}
  .sel-delete-btn{width:30px;height:30px;border-radius:8px;border:none;background:none;color:#fff;display:flex;align-items:center;justify-content:center;cursor:pointer;transition:background .15s,transform .1s}
  .sel-delete-btn:hover{background:rgba(255,255,255,.15)}
  .sel-delete-btn:active{transform:scale(.9)}
  .sel-icon-badge-wrap{position:relative;display:inline-flex}
  .sel-icon-badge{position:absolute;right:-5px;bottom:-5px;font-size:9px;background:#2BA08A;color:#fff;border-radius:50%;width:12px;height:12px;display:flex;align-items:center;justify-content:center;border:1.5px solid #0D1B2E}
  .hold-ring svg{width:100%;height:100%;transform:rotate(-90deg)}
  .hold-ring circle{fill:none;stroke-width:3}
  .hold-ring .bg{stroke:rgba(13,27,46,.1)}
  .hold-ring .fg{stroke:#2BA08A;stroke-dasharray:113;stroke-dashoffset:113;transition:stroke-dashoffset linear}
  .snap-toast{position:absolute;top:60px;left:50%;transform:translateX(-50%) translateY(-8px);background:#0D1B2E;color:#fff;font-size:11.5px;font-weight:600;padding:7px 8px 7px 14px;border-radius:20px;opacity:0;transition:all .25s cubic-bezier(.34,1.4,.64,1);z-index:25;display:flex;align-items:center;gap:10px;pointer-events:none}
  .snap-toast.show{opacity:1;transform:translateX(-50%) translateY(0);pointer-events:auto}
  .undo-btn{background:rgba(255,255,255,.15);border:none;color:#fff;font-size:11px;font-weight:600;padding:5px 10px;border-radius:8px;cursor:pointer;transition:background .15s,transform .1s}
  .undo-btn:active{transform:scale(.94)}

  .hover-zone-top{position:absolute;top:0;left:0;right:0;height:60px;z-index:9;pointer-events:none}
  .hover-zone-top.focus-hover-active{pointer-events:auto}

  .chapter-sidebar{position:absolute;top:59px;left:0;bottom:0;width:220px;background:#FFFFFF;border-right:1px solid #EBEAE5;z-index:12;padding:16px 12px;overflow-y:auto}
  .chapter-sidebar.collapsed{transform:translateX(-220px)}
  .chapter-sidebar-label{font-size:10px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:#B8B7B0;padding:0 8px;margin-bottom:8px}
  .chapter-session-item{display:flex;align-items:center;gap:8px;padding:9px 10px;border-radius:8px;font-size:12.5px;color:#4A4944;cursor:pointer;margin-bottom:2px}
  .chapter-session-item:hover{background:#F5F4EF}
  .chapter-session-item.active{background:#0D1B2E;color:#fff}
  .chapter-session-item .sess-dot{width:6px;height:6px;border-radius:50%;background:currentColor;opacity:.5;flex-shrink:0}
  .session-group-header{display:flex;align-items:center;gap:8px;padding:9px 10px;border-radius:8px;font-size:12.5px;font-weight:600;color:#4A4944;cursor:pointer;margin-bottom:2px}
  .session-group-header:hover{background:#F5F4EF}
  .session-group-header.active{background:#0D1B2E;color:#fff}
  .session-group-header .sess-dot{width:6px;height:6px;border-radius:50%;background:currentColor;opacity:.5;flex-shrink:0}
  .session-page-subitem{display:flex;align-items:center;gap:8px;padding:6px 10px 6px 26px;border-radius:8px;font-size:11.5px;color:#8B8A84;cursor:pointer}
  .page-delete-btn{background:none;border:none;color:#C0C7D6;cursor:pointer;padding:3px;border-radius:5px;display:flex;align-items:center;justify-content:center;opacity:0;transition:opacity .15s,color .15s,background .15s;flex-shrink:0}
  .session-page-subitem:hover .page-delete-btn{opacity:1}
  .page-delete-btn:hover{color:#DC2626;background:#FEF2F2}
  .sidebar-thumb{width:30px;height:19px;border-radius:4px;object-fit:cover;border:1px solid rgba(0,0,0,.1);flex-shrink:0;background:#FDFBF7}
  .sidebar-thumb-empty{display:inline-block;border-style:dashed;border-color:rgba(0,0,0,.12)}
  .session-group-header.active .sidebar-thumb{border-color:rgba(255,255,255,.25)}
  .session-page-subitem:hover{background:#F5F4EF}
  .session-page-subitem.active{background:#E8F5F2;color:#1D8A74;font-weight:600}
  .session-page-count{font-size:10px;color:#B8B7B0;margin-left:auto;font-weight:400}
  .canvas-wrap.with-sidebar{left:220px}
  .canvas-wrap.with-sidebar.sidebar-collapsed{left:0}

  .chapter-sidebar.auto-collapsed{transform:translateX(-220px)}
  .hover-zone-left{position:absolute;top:59px;left:0;bottom:0;width:14px;z-index:13}
  .sidebar-handle{position:absolute;top:50%;left:0;transform:translateY(-50%);width:5px;height:44px;background:#DEDCD3;border-radius:0 4px 4px 0;z-index:13;transition:background .15s,width .15s,opacity .2s;cursor:pointer}
  .sidebar-handle:hover{background:#0D1B2E;width:7px}
  .sidebar-handle.handle-hidden{opacity:0;pointer-events:none}