body{margin:0;font-family:Segoe UI,Arial,sans-serif;background:#f4f5f7;color:#172b4d;}
.topbar{background:#0747a6;color:#fff;padding:10px 16px;display:flex;gap:10px;align-items:center;}
.layout{display:flex;height:calc(100vh - 48px);}
.sidebar{width:260px;background:#fff;border-right:1px solid #ddd;overflow:auto;padding:12px;}
.content{flex:1;padding:40px;overflow:auto;}
.page{background:#fff;padding:48px;min-height:80vh;}
.tree-item{cursor:pointer;padding:6px;border-radius:4px;}
.tree-item:hover{background:#e9f2ff;}
.children{margin-left:18px;}
button{padding:6px 10px;margin-right:6px;}
.toolbar{margin-bottom:12px;}
.toc{background:#f1f2f4;padding:12px;margin-bottom:16px;}