:root{--bg-color:#0f172a;--bg-gradient:linear-gradient(135deg, #0f172a 0%, #1e293b 100%);--sidebar-bg:#1e293b99;--glass-border:#ffffff14;--text-main:#f8fafc;--text-muted:#94a3b8;--accent:#3b82f6;--accent-hover:#60a5fa;--hover-bg:#ffffff0d;--active-bg:#3b82f626;--active-border:#3b82f666}*{box-sizing:border-box;margin:0;padding:0}body{background:var(--bg-gradient);color:var(--text-main);-webkit-font-smoothing:antialiased;height:100vh;font-family:Inter,system-ui,-apple-system,sans-serif;overflow:hidden}.app-container{width:100vw;height:100vh;display:flex}.sidebar{background:var(--sidebar-bg);-webkit-backdrop-filter:blur(16px);border-right:1px solid var(--glass-border);z-index:10;flex-direction:column;width:350px;min-width:350px;transition:transform .3s cubic-bezier(.4,0,.2,1);display:flex;overflow-y:auto;box-shadow:4px 0 24px #0003}.sidebar::-webkit-scrollbar{width:6px}.sidebar::-webkit-scrollbar-thumb{background:#ffffff1a;border-radius:3px}.sidebar-header{border-bottom:1px solid var(--glass-border);align-items:center;gap:12px;padding:24px 20px;display:flex}.sidebar-header h1{background:linear-gradient(90deg,#60a5fa,#a78bfa);-webkit-text-fill-color:transparent;letter-spacing:-.02em;-webkit-background-clip:text;font-size:1.25rem;font-weight:600}.tree-node{flex-direction:column;display:flex}.tree-item{cursor:pointer;color:var(--text-muted);-webkit-user-select:none;user-select:none;border:1px solid #0000;border-radius:8px;align-items:center;margin:2px 12px;padding:8px 12px;font-size:.9rem;transition:all .2s;display:flex}.tree-item:hover{background:var(--hover-bg);color:var(--text-main)}.tree-item.active{background:var(--active-bg);color:var(--accent-hover);border:1px solid var(--active-border)}.tree-item-icon{opacity:.8;justify-content:center;align-items:center;margin-right:10px;display:flex}.tree-item.active .tree-item-icon{opacity:1;color:var(--accent-hover)}.tree-children{border-left:1px dashed #ffffff1a;margin-left:20px;padding-left:4px}.main-content{background:var(--bg-color);flex-direction:column;flex:1;display:flex;position:relative}.top-bar{-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border-bottom:1px solid var(--glass-border);height:60px;color:var(--text-muted);background:#0f172acc;align-items:center;padding:0 24px;font-size:.9rem;display:flex}.breadcrumb,.breadcrumb-item{align-items:center;gap:8px;display:flex}.breadcrumb-separator{opacity:.4}.viewer-container{background:#2a2a2a;flex:1;position:relative}.pdf-iframe{background:#fff;border:none;width:100%;height:100%}.empty-state{color:var(--text-muted);opacity:.7;flex-direction:column;align-items:center;gap:16px;display:flex;position:absolute;top:50%;left:50%;transform:translate(-50%,-50%)}.empty-state-icon{width:64px;height:64px;color:var(--glass-border)}.resizer{cursor:col-resize;z-index:20;background:0 0;width:5px;transition:background .2s;position:relative}.resizer:hover,.resizer:active{background:var(--accent)}.sidebar-toggle{color:var(--text-muted);cursor:pointer;background:0 0;border:none;border-radius:6px;justify-content:center;align-items:center;margin-right:16px;padding:6px;transition:all .2s;display:flex}.sidebar-toggle:hover{background:var(--hover-bg);color:var(--text-main)}