sidebar improvements

src/components/EstimateBuilder.tsx

@@ -219,6 +219,7 @@ const EstimateBuilder: Component<EstimateBuilderProps> = (props) => {
                 >
                     <BuilderSidebar
                         isCollapsed={isSidebarCollapsed()}
+                        onToggleSidebar={() => setIsSidebarCollapsed(!isSidebarCollapsed())}
                         unassignedItems={unassignedItems()}
                         grandTotals={grandTotals()}
                         hoveredScopeId={hoveredScopeId()}

src/components/estimate-builder/BuilderHeader.tsx

@@ -1,6 +1,6 @@
 import { createSignal, onCleanup, Show } from 'solid-js';
 import type { Component } from 'solid-js';
-import { PanelLeftOpen, PanelLeftClose, Calculator, Plus, Upload, Table, Download, History, Save, ChevronDown, MoreHorizontal } from 'lucide-solid';
+import { Calculator, Plus, Upload, Table, Download, History, Save, ChevronDown, MoreHorizontal } from 'lucide-solid';
 import { appStore } from '../../store/appStore';
 
 interface BuilderHeaderProps {
@@ -34,13 +34,6 @@ export const BuilderHeader: Component<BuilderHeaderProps> = (props) => {
     return (
         <div class="min-h-[4rem] py-3 px-6 border-b border-border bg-background/50 flex flex-wrap gap-y-4 items-center justify-between sticky top-0 z-50 backdrop-blur-md">
             <div class="flex items-center gap-4">
-                <button
-                    onClick={props.onToggleSidebar}
-                    class="p-2 hover:bg-accent rounded-xl transition-colors text-muted-foreground shrink-0"
-                    title={props.isSidebarCollapsed ? "Expand Sidebar" : "Collapse Sidebar"}
-                >
-                    {props.isSidebarCollapsed ? <PanelLeftOpen class="w-5 h-5" /> : <PanelLeftClose class="w-5 h-5" />}
-                </button>
                 <div class="flex items-center gap-3">
                     <div class="p-2 bg-primary rounded-xl text-primary-foreground shadow-md shadow-primary/20 shrink-0">
                         <Calculator class="w-5 h-5" />

src/components/estimate-builder/BuilderSidebar.tsx

@@ -1,11 +1,12 @@
 import type { Component } from 'solid-js';
 import { For } from 'solid-js';
-import { Plus, ListTree, ChevronRight } from 'lucide-solid';
+import { Plus, ListTree, ChevronRight, PanelLeftOpen, PanelLeftClose } from 'lucide-solid';
 import { appStore } from '../../store/appStore';
 import type { EstimateItem } from '../../types';
 
 interface BuilderSidebarProps {
     isCollapsed: boolean;
+    onToggleSidebar: () => void;
     unassignedItems: EstimateItem[];
     grandTotals: { grandTotal: number };
     hoveredScopeId: string | null;
@@ -24,15 +25,40 @@ export const BuilderSidebar: Component<BuilderSidebarProps> = (props) => {
     return (
         /*
          * The sidebar sits inside a CSS grid column (in EstimateBuilder.tsx).
-         * It fills its column completely. When the column width transitions to 0,
-         * the sidebar content is clipped by overflow-hidden on this element.
-         * This means the main content genuinely reclaims the space.
+         * We use overflow-visible on the aside so the toggle button can remain 
+         * visible and clickable even when the grid column width is 0px.
          */
         <aside
-            class="h-[calc(100vh-var(--spacing-header))] sticky top-[var(--spacing-header)] bg-background border-r border-border flex flex-col overflow-hidden"
+            class="h-[calc(100vh-var(--spacing-header))] sticky top-[var(--spacing-header)] bg-background border-r border-border flex flex-col overflow-visible z-40 transition-colors"
             style={{ "min-width": 0 }}
         >
-            <div class="flex-1 overflow-y-auto overflow-x-hidden px-4 py-8 w-72">
+            {/* 
+             * Sticky Toggle Button 
+             * Anchored to the right edge (100% width) of the sidebar column.
+             * As the column width animates, the button follows perfectly.
+             * We use translateX to adjust horizontal offset from the edge.
+             */}
+            <button
+                onClick={props.onToggleSidebar}
+                class="absolute top-4 z-50 w-10 h-10 bg-background hover:bg-accent rounded-xl transition-all duration-500 ease-in-out shadow-premium border border-border text-muted-foreground hover:text-primary active:scale-95 flex items-center justify-center cursor-pointer"
+                style={{
+                    left: '100%',
+                    transform: props.isCollapsed 
+                        ? 'translateX(1.25rem)'  // When closed (0px width), sit 20px off the left edge
+                        : 'translateX(-0.5rem)'  // When open, hang 80% out to the right (overlap only 8px)
+                }}
+                title={props.isCollapsed ? "Expand Sidebar" : "Collapse Sidebar"}
+            >
+                {props.isCollapsed ? <PanelLeftOpen class="w-5 h-5" /> : <PanelLeftClose class="w-5 h-5" />}
+            </button>
+
+            {/* 
+             * Sidebar Content Wrapper 
+             * We apply the overflow-hidden here so the content doesn't leak out 
+             * when the grid column is 0px.
+             */}
+            <div class={`flex-1 overflow-y-auto overflow-x-hidden transition-all duration-500 flex flex-col ${props.isCollapsed ? 'w-0 opacity-0 pointer-events-none' : 'w-72 opacity-100'}`}>
+                <div class="flex-1 px-4 py-8">
                     <div class="mb-4">
                         <div class="flex items-center justify-between mb-4 px-2">
                             <span class="text-[10px] font-black text-muted-foreground uppercase tracking-[0.2em] whitespace-nowrap">Estimate Navigator</span>
@@ -144,6 +170,7 @@ export const BuilderSidebar: Component<BuilderSidebarProps> = (props) => {
                         </div>
                     </div>
                 </div>
+            </div>
         </aside>
     );
 };