:root{--base-color:#0D5182;--base-color-hover:#0a416a;--base-color-light:#e8f1f8;--text-primary:#1f2937;--text-secondary:#6b7280;--text-muted:#9ca3af;--border-color:#e5e7eb;--bg-app:#f5f7fa;--bg-surface:#ffffff;--bg-hover:#f3f4f6;--bg-active:var(--base-color-light);--shadow-sm:0 1px 2px rgba(0,0,0,0.04);--shadow-md:0 4px 12px rgba(0,0,0,0.08);--shadow-lg:0 8px 24px rgba(0,0,0,0.12);--radius-sm:4px;--radius-md:6px;--radius-lg:10px;--topbar-height:56px;--sidebar-width:260px;--tabbar-height:40px;--transition:all 0.2s ease}*{box-sizing:border-box}body,html{height:100%;margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;color:var(--text-primary);background:var(--bg-app);font-size:14px;-webkit-font-smoothing:antialiased}button{font-family:inherit;cursor:pointer;border:none;background:0 0}a{color:inherit;text-decoration:none}ul{list-style:none;margin:0;padding:0}.app{display:grid;grid-template-columns:var(--sidebar-width) 1fr;grid-template-rows:var(--topbar-height) 1fr;grid-template-areas:"topbar topbar" "sidebar content";height:100vh;overflow:hidden}.topbar{grid-area:topbar;display:flex;align-items:center;gap:12px;padding:0 20px;background:var(--bg-surface);border-bottom:1px solid var(--border-color);box-shadow:var(--shadow-sm);z-index:10}.menu-toggle{display:none;width:36px;height:36px;border-radius:var(--radius-md);color:var(--text-primary);transition:var(--transition)}.menu-toggle:hover{background:var(--bg-hover)}.brand{display:flex;align-items:baseline;gap:12px;min-width:0}.brand-title{font-size:18px;font-weight:600;color:var(--base-color);white-space:nowrap}.brand-slogan{font-size:12px;color:var(--text-muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.topbar-spacer{flex:1}.topbar-links{display:flex;gap:4px}.topbar-links a{padding:6px 12px;border-radius:var(--radius-md);color:var(--text-secondary);font-size:14px;transition:var(--transition)}.topbar-links a:hover{color:var(--base-color);background:var(--base-color-light)}.topbar-btn{display:inline-flex;align-items:center;gap:6px;padding:7px 14px;border-radius:var(--radius-md);font-size:14px;font-weight:500;transition:var(--transition);white-space:nowrap}.topbar-btn.ghost{color:var(--base-color);background:var(--base-color-light)}.topbar-btn.ghost:hover{background:#d6e6f2}.topbar-btn.primary{color:#fff;background:var(--base-color)}.topbar-btn.primary:hover{background:var(--base-color-hover)}.sidebar{grid-area:sidebar;display:flex;flex-direction:column;background:var(--bg-surface);border-right:1px solid var(--border-color);overflow:hidden;transition:transform .25s ease}.sidebar-header{display:flex;align-items:center;gap:8px;padding:14px 18px;font-size:13px;font-weight:600;color:var(--text-secondary);border-bottom:1px solid var(--border-color)}.tree-wrapper{flex:1;overflow-y:auto;padding:8px 6px}.tree-status{padding:16px;font-size:13px;color:var(--text-muted);text-align:center}.tree-status button{margin-top:8px;padding:4px 12px;color:var(--base-color);border:1px solid var(--base-color);border-radius:var(--radius-sm)}.tree-node{user-select:none}.tree-row{display:flex;align-items:center;gap:6px;padding:6px 8px;margin:1px 0;border-radius:var(--radius-md);cursor:pointer;color:var(--text-primary);font-size:13px;transition:var(--transition);position:relative}.tree-row:hover{background:var(--bg-hover)}.tree-row.active{background:var(--bg-active);color:var(--base-color);font-weight:500}.tree-row.active::before{content:"";position:absolute;left:0;top:6px;bottom:6px;width:3px;background:var(--base-color);border-radius:0 2px 2px 0}.tree-toggle{width:16px;height:16px;display:inline-flex;align-items:center;justify-content:center;color:var(--text-muted);flex-shrink:0;transition:transform .2s ease}.tree-toggle.collapsed{transform:rotate(-90deg)}.tree-toggle.empty{visibility:hidden}.tree-icon{width:16px;text-align:center;color:var(--text-secondary);flex-shrink:0}.tree-row.active .tree-icon{color:var(--base-color)}.tree-label{flex:1;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.tree-children{overflow:hidden;transition:max-height .25s ease}.tree-children.collapsed{display:none}.tree-children .tree-row{padding-left:22px}.tree-children .tree-children .tree-row{padding-left:38px}.content{grid-area:content;display:flex;flex-direction:column;overflow:hidden;background:var(--bg-app)}.tabbar{display:flex;align-items:stretch;height:var(--tabbar-height);background:var(--bg-surface);border-bottom:1px solid var(--border-color);flex-shrink:0}.tabs-scroll{flex:1;overflow-x:auto;overflow-y:hidden;scrollbar-width:none}.tabs-scroll::-webkit-scrollbar{display:none}.tabs{display:flex;align-items:stretch;height:100%;padding:4px 0 0 4px}.tab{display:inline-flex;align-items:center;gap:6px;padding:0 10px 0 12px;height:calc(var(--tabbar-height) - 4px);background:0 0;color:var(--text-secondary);border-radius:var(--radius-md) var(--radius-md) 0 0;border:1px solid transparent;border-bottom:none;font-size:13px;cursor:pointer;user-select:none;transition:var(--transition);flex-shrink:0;max-width:220px;position:relative}.tab:hover{background:var(--bg-hover);color:var(--text-primary)}.tab.active{background:var(--bg-app);color:var(--base-color);border-color:var(--border-color);font-weight:500;margin-bottom:-1px;z-index:1}.tab-icon{width:14px;text-align:center;flex-shrink:0;font-size:12px}.tab-title{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.tab-close{width:18px;height:18px;display:inline-flex;align-items:center;justify-content:center;border-radius:50%;color:var(--text-muted);font-size:11px;flex-shrink:0;transition:var(--transition)}.tab-close:hover{background:rgba(0,0,0,.1);color:var(--text-primary)}.tab.dragging{opacity:.5}.tab.drag-over::after{content:"";position:absolute;left:-1px;top:4px;bottom:0;width:2px;background:var(--base-color)}.tab-overflow{width:36px;color:var(--text-secondary);border-left:1px solid var(--border-color);transition:var(--transition)}.tab-overflow:hover{background:var(--bg-hover);color:var(--base-color)}.frames{flex:1;position:relative;overflow:hidden;background:var(--bg-surface)}.frame{position:absolute;inset:0;width:100%;height:100%;border:0;background:#fff;display:none}.frame.active{display:block}.ctx-menu,.overflow-menu{position:fixed;min-width:160px;background:var(--bg-surface);border:1px solid var(--border-color);border-radius:var(--radius-md);box-shadow:var(--shadow-lg);padding:4px;z-index:1000;font-size:13px}.ctx-menu-item,.overflow-menu-item{display:flex;align-items:center;gap:8px;padding:7px 12px;border-radius:var(--radius-sm);cursor:pointer;color:var(--text-primary);transition:var(--transition);white-space:nowrap}.ctx-menu-item:hover,.overflow-menu-item:hover{background:var(--base-color-light);color:var(--base-color)}.ctx-menu-item.disabled{color:var(--text-muted);cursor:not-allowed}.ctx-menu-item.disabled:hover{background:0 0;color:var(--text-muted)}.ctx-menu-divider{height:1px;background:var(--border-color);margin:4px 0}.overflow-menu{max-height:60vh;overflow-y:auto}.overflow-menu-item.active{background:var(--base-color-light);color:var(--base-color);font-weight:500}.sidebar-mask{position:fixed;inset:0;background:rgba(0,0,0,.4);z-index:50}@media (max-width:900px){.app{grid-template-columns:1fr;grid-template-areas:"topbar" "content"}.menu-toggle{display:inline-flex}.topbar-links{display:none}.brand-slogan{display:none}.sidebar{position:fixed;top:var(--topbar-height);left:0;bottom:0;width:var(--sidebar-width);z-index:60;transform:translateX(-100%);box-shadow:var(--shadow-lg)}.sidebar.open{transform:translateX(0)}}.overflow-menu::-webkit-scrollbar,.tree-wrapper::-webkit-scrollbar{width:6px}.overflow-menu::-webkit-scrollbar-thumb,.tree-wrapper::-webkit-scrollbar-thumb{background:#d1d5db;border-radius:3px}.overflow-menu::-webkit-scrollbar-thumb:hover,.tree-wrapper::-webkit-scrollbar-thumb:hover{background:#9ca3af}