:root{color-scheme:light;--bg:#f5f7f8;--surface:#fff;--surface-soft:#f8fafb;--line:#dce3e6;--text:#20282d;--muted:#68757b;--accent:#156d66;--accent-soft:#e5f3f0;--orange:#bf672b;--danger:#a33333;--shadow:0 1px 2px #1d2b3310;--radius:6px;font:14px/1.45 -apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);min-width:320px}.lesson-app{min-height:100vh;display:flex;flex-direction:column}.topbar{height:68px;padding:0 20px;background:var(--surface);border-bottom:1px solid var(--line);display:flex;align-items:center;gap:24px}.brand{display:flex;align-items:center;gap:11px;min-width:210px}.brand-mark{width:34px;height:34px;display:grid;place-items:center;border-radius:7px;background:var(--accent);color:#fff;font-weight:700;font-size:12px}.brand h1{margin:0;font-size:16px;font-weight:650}.brand p{margin:1px 0 0;color:var(--muted);font-size:12px}.search-box{height:36px;max-width:440px;flex:1;display:flex;align-items:center;gap:8px;padding:0 10px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface-soft);color:var(--muted)}.search-box span{font-size:20px}.search-box input{width:100%;border:0;outline:0;background:transparent;color:var(--text);font:inherit;font-size:13px}.top-actions{margin-left:auto;display:flex;align-items:center;gap:8px}.local-state{display:flex;align-items:center;gap:7px;padding:0 8px;color:var(--muted);font-size:12px;white-space:nowrap}.local-state i{width:7px;height:7px;border-radius:50%;background:#28865e}.tool-button,.primary-button,.icon-button,.small-icon{height:34px;padding:0 10px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);color:var(--text);font:inherit;cursor:pointer}.icon-button{min-width:36px;padding:0 8px}.primary-button{border-color:var(--accent);background:var(--accent);color:#fff;font-weight:600}.tool-button:hover,.icon-button:hover,.small-icon:hover{background:var(--surface-soft)}.primary-button:hover{filter:brightness(.94)}button:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible{outline:2px solid #3c958a;outline-offset:2px}.workspace{min-height:0;flex:1;display:grid;grid-template-columns:230px minmax(270px,330px) minmax(350px,1fr)}.tree-pane,.list-pane,.detail-pane{min-width:0;background:var(--surface)}.tree-pane{border-right:1px solid var(--line);display:flex;flex-direction:column}.list-pane{border-right:1px solid var(--line);display:flex;flex-direction:column}.pane-heading{min-height:58px;padding:12px 14px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between}.pane-heading h2{margin:0;font-size:13px;font-weight:650}.pane-heading p{margin:3px 0 0;color:var(--muted);font-size:11px}.pane-heading>div:last-child{display:flex;gap:5px}.small-icon{height:28px;width:28px;padding:0;font-size:16px;color:var(--muted)}.page-tree{overflow:auto;padding:10px 8px;flex:1}.tree-space{margin-bottom:10px}.tree-space-title,.tree-page{width:100%;min-height:32px;border:0;border-radius:4px;background:transparent;color:var(--text);font:inherit;text-align:left;cursor:pointer}.tree-space-title{padding:5px 8px;font-weight:650}.tree-space-title::before{content:"▾";display:inline-block;width:18px;color:var(--muted)}.tree-page{padding:5px 8px 5px 27px;color:var(--muted);font-size:13px;overflow-wrap:anywhere}.tree-page::before{content:"▤";display:inline-block;width:17px;color:#849096}.tree-page.active{background:var(--accent-soft);color:var(--accent);font-weight:600}.tree-page:hover,.tree-space-title:hover{background:var(--surface-soft)}.tree-footer{padding:11px 14px;border-top:1px solid var(--line);color:var(--muted);font-size:11px}.list-heading{min-height:58px}.lesson-list{padding:8px;overflow:auto}.lesson-row{width:100%;padding:11px 10px;border:0;border-bottom:1px solid var(--line);border-radius:4px;background:transparent;color:var(--text);text-align:left;cursor:pointer}.lesson-row:hover{background:var(--surface-soft)}.lesson-row.active{background:var(--accent-soft);box-shadow:inset 2px 0 var(--accent)}.lesson-row strong{display:block;font-size:13px;font-weight:600;overflow-wrap:anywhere}.lesson-row small{display:block;margin-top:5px;color:var(--muted);font-size:11px}.status-dot{display:inline-block;width:7px;height:7px;margin-right:5px;border-radius:50%;background:var(--orange)}.status-dot.resolved{background:#25865b}.status-dot.in-progress{background:#507eb0}.empty-list{padding:28px 12px;color:var(--muted);text-align:center;font-size:12px}.detail-pane{padding:26px clamp(18px,4vw,52px);overflow:auto}.detail-empty{height:100%;min-height:240px;display:grid;place-content:center;text-align:center;color:var(--muted)}.detail-empty strong{color:var(--text);font-size:15px;font-weight:600}.detail-empty p{max-width:290px;margin:7px auto 0;font-size:12px}.detail-header{padding-bottom:17px;border-bottom:1px solid var(--line);display:flex;align-items:flex-start;gap:16px}.detail-header h2{margin:0;font-size:21px;line-height:1.3;overflow-wrap:anywhere}.detail-header p{margin:8px 0 0;color:var(--muted);font-size:12px}.detail-actions{margin-left:auto;flex:none}.status-label{display:inline-flex;align-items:center;gap:6px;padding:4px 8px;border:1px solid var(--line);border-radius:4px;color:var(--muted);font-size:11px}.detail-body{max-width:850px}.content-block{padding:16px 0 13px;border-bottom:1px solid var(--line)}.content-block h3{margin:0 0 7px;color:var(--muted);font-size:11px;font-weight:650;text-transform:uppercase}.content-block p{margin:0;white-space:pre-wrap;overflow-wrap:anywhere;line-height:1.65}.relation-list,.tag-list{display:flex;flex-wrap:wrap;gap:6px}.relation-chip,.tag-chip{padding:4px 8px;border:1px solid var(--line);border-radius:4px;background:var(--surface-soft);font-size:11px;overflow-wrap:anywhere}.tag-chip{border-color:#d2e8e2;background:var(--accent-soft);color:var(--accent)}.lesson-form{max-width:780px}.form-top{padding-bottom:15px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:10px}.form-top h2{margin:0;font-size:18px}.form-actions{display:flex;gap:7px}.field-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px 18px;padding-top:16px}.field{display:flex;flex-direction:column;gap:5px;min-width:0}.field.full{grid-column:1/-1}.field label{color:var(--muted);font-size:11px;font-weight:600}.field input,.field textarea,.field select,.name-dialog input,.name-dialog select{width:100%;min-height:36px;padding:8px 9px;border:1px solid var(--line);border-radius:4px;background:var(--surface);color:var(--text);font:inherit}.field textarea{min-height:88px;resize:vertical}.field input::placeholder,.field textarea::placeholder{color:#929da2}.form-note{margin:13px 0 0;color:var(--muted);font-size:11px}.name-dialog{width:min(420px,calc(100vw - 30px));padding:20px;border:1px solid var(--line);border-radius:7px;background:var(--surface);color:var(--text);box-shadow:0 20px 60px #0003}.name-dialog::backdrop{background:#17212666}.name-dialog h2{margin:0 0 17px;font-size:16px}.name-dialog label{display:flex;flex-direction:column;gap:6px;margin-bottom:12px;color:var(--muted);font-size:12px}.dialog-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:18px}.toast{position:fixed;right:18px;bottom:18px;max-width:min(420px,calc(100vw - 36px));padding:10px 14px;border:1px solid var(--line);border-radius:5px;background:var(--surface);box-shadow:var(--shadow);opacity:0;transform:translateY(6px);transition:opacity .16s,transform .16s;pointer-events:none}.toast.visible{opacity:1;transform:translateY(0)}.toast.error{border-color:#dfb9b9;color:var(--danger)}
:root[data-theme="dark"]{color-scheme:dark;--bg:#161c1f;--surface:#20282c;--surface-soft:#252e32;--line:#39454a;--text:#e7edef;--muted:#a3afb3;--accent:#57b5a5;--accent-soft:#233d3a;--orange:#e6a06f;--danger:#e69b9b;--shadow:0 1px 3px #0004} :root[data-theme="dark"] .tag-chip{border-color:#345852}:root[data-theme="dark"] .status-dot.resolved{background:#66bd8b}@media(max-width:850px){.topbar{height:auto;min-height:68px;flex-wrap:wrap;padding:10px 14px;gap:10px}.brand{min-width:0;flex:1}.search-box{order:3;max-width:none;flex-basis:100%}.top-actions{gap:5px}.local-state{display:none}.workspace{grid-template-columns:190px minmax(230px,1fr)}.detail-pane{grid-column:1/-1;min-height:45vh;border-top:1px solid var(--line)}.list-pane{border-right:0}}@media(max-width:560px){.workspace{grid-template-columns:1fr}.tree-pane{max-height:210px;border-right:0;border-bottom:1px solid var(--line)}.list-pane{max-height:310px;border-bottom:1px solid var(--line)}.detail-pane{grid-column:auto;padding:20px 16px}.top-actions .tool-button{display:none}.top-actions{margin-left:0}.brand{flex:1}.field-grid{grid-template-columns:1fr}.field.full{grid-column:auto}.detail-header h2{font-size:18px}}
:root{--tab-line:#dce3e6}
.list-actions{display:flex;gap:5px}
.view-tabs{display:flex;gap:2px;padding:7px 10px 0;border-bottom:1px solid var(--line);background:var(--surface)}
.view-tab{flex:1;height:30px;border:0;border-bottom:2px solid transparent;background:transparent;color:var(--muted);font:inherit;font-size:12px;cursor:pointer}
.view-tab:hover{background:var(--surface-soft);color:var(--text)}
.view-tab.active{border-bottom-color:var(--accent);color:var(--accent);font-weight:650}
.activity-row{display:flex;gap:9px;padding:12px 10px;border-bottom:1px solid var(--line)}
.activity-row strong{display:block;font-size:12px;overflow-wrap:anywhere}
.activity-row small{display:block;margin-top:4px;color:var(--muted);font-size:11px}
.activity-mark{color:var(--accent);font-size:18px;line-height:1}
.history-block{margin-top:6px}
.history-row{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:10px 0;border-top:1px solid var(--line)}
.history-row strong{display:block;font-size:12px;font-weight:600;overflow-wrap:anywhere}
.history-row small{display:block;margin-top:3px;color:var(--muted);font-size:11px}
.history-row .tool-button{height:28px;padding:0 8px;font-size:11px;white-space:nowrap}
.detail-actions{display:flex;align-items:center;gap:7px;flex-wrap:wrap;justify-content:flex-end}
.detail-actions .tool-button{white-space:nowrap}
.detail-header>.tool-button{margin-left:auto}
.content-block pre,.content-block p{max-width:100%}
@media(max-width:720px){.detail-header{flex-wrap:wrap}.detail-header>.tool-button{margin-left:0}.detail-actions{width:100%;justify-content:flex-start}.history-row{align-items:flex-start;flex-direction:column}.history-row .tool-button{align-self:flex-start}}