diff --git a/CHANGELOG.md b/CHANGELOG.md
index af083b9..fa3a035 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,10 @@ The format follows *Keep a Changelog*. Versions use semantic versioning with pre
 
 ### Fixed
 - Fixed missing diagnostics reset workflow by adding a dedicated `Clear Diagnostics` action that also clears file-open timing snapshots.
+- Fixed macOS editor-window top-bar jumping when toggling the toolbar translucency control by keeping chrome flags stable.
+- Fixed CSV/TSV mode header transparency so the mode bar now uses a solid standard window background.
+- Fixed settings-window translucency consistency on macOS so title/tab and content regions render as one unified surface.
+- Fixed cross-platform updater diagnostics compilation by adding a non-macOS bundle-version reader fallback.
 
 ## [Unreleased]
 
diff --git a/Neon Vision Editor.xcodeproj/project.pbxproj b/Neon Vision Editor.xcodeproj/project.pbxproj
index f1e5594..11e910e 100644
--- a/Neon Vision Editor.xcodeproj/project.pbxproj	
+++ b/Neon Vision Editor.xcodeproj/project.pbxproj	
@@ -361,7 +361,7 @@
 				CODE_SIGNING_ALLOWED = YES;
 				CODE_SIGN_IDENTITY = "Apple Development";
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 451;
+				CURRENT_PROJECT_VERSION = 452;
 				DEAD_CODE_STRIPPING = YES;
 				DEVELOPMENT_TEAM = CS727NF72U;
 				ENABLE_APP_SANDBOX = YES;
@@ -444,7 +444,7 @@
 				CODE_SIGNING_ALLOWED = YES;
 				CODE_SIGN_IDENTITY = "Apple Development";
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 451;
+				CURRENT_PROJECT_VERSION = 452;
 				DEAD_CODE_STRIPPING = YES;
 				DEVELOPMENT_TEAM = CS727NF72U;
 				ENABLE_APP_SANDBOX = YES;
diff --git a/Neon Vision Editor/AI/AIClient.swift b/Neon Vision Editor/AI/AIClient.swift
index 569a075..176ba59 100644
--- a/Neon Vision Editor/AI/AIClient.swift	
+++ b/Neon Vision Editor/AI/AIClient.swift	
@@ -6,6 +6,7 @@ import FoundationModels
 
 #if false
 // This enum is defined in ContentView.swift; this is here to avoid redefinition errors.
+
 public enum AIModel {
     case appleIntelligence
     case grok
@@ -15,6 +16,8 @@ public enum AIModel {
 }
 #endif
 
+/// MARK: - Types
+
 public protocol AIClient {
     func streamSuggestions(prompt: String) -> AsyncStream<String>
 }
diff --git a/Neon Vision Editor/App/AppMenus.swift b/Neon Vision Editor/App/AppMenus.swift
index 5387e80..ab3cb83 100644
--- a/Neon Vision Editor/App/AppMenus.swift	
+++ b/Neon Vision Editor/App/AppMenus.swift	
@@ -4,6 +4,10 @@ import SwiftUI
 import FoundationModels
 #endif
 
+
+
+/// MARK: - Types
+
 struct NeonVisionMacAppCommands: Commands {
     let activeEditorViewModel: () -> EditorViewModel
     let hasActiveEditorWindow: () -> Bool
diff --git a/Neon Vision Editor/App/NeonVisionEditorApp.swift b/Neon Vision Editor/App/NeonVisionEditorApp.swift
index 9720de6..8a54a88 100644
--- a/Neon Vision Editor/App/NeonVisionEditorApp.swift	
+++ b/Neon Vision Editor/App/NeonVisionEditorApp.swift	
@@ -10,6 +10,10 @@ import UIKit
 #endif
 
 #if os(macOS)
+
+
+/// MARK: - Types
+
 final class AppDelegate: NSObject, NSApplicationDelegate {
     weak var viewModel: EditorViewModel? {
         didSet {
diff --git a/Neon Vision Editor/Core/AIActivityLog.swift b/Neon Vision Editor/Core/AIActivityLog.swift
index 08e98cc..df0e8be 100644
--- a/Neon Vision Editor/Core/AIActivityLog.swift	
+++ b/Neon Vision Editor/Core/AIActivityLog.swift	
@@ -3,6 +3,10 @@ import Observation
 
 @MainActor
 @Observable
+
+
+/// MARK: - Types
+
 final class AIActivityLog {
     enum Level: String, CaseIterable {
         case info = "INFO"
diff --git a/Neon Vision Editor/Core/AppUpdateManager.swift b/Neon Vision Editor/Core/AppUpdateManager.swift
index b0c9373..899c2a5 100644
--- a/Neon Vision Editor/Core/AppUpdateManager.swift	
+++ b/Neon Vision Editor/Core/AppUpdateManager.swift	
@@ -13,6 +13,10 @@ import AppKit
 import UIKit
 #endif
 
+
+
+/// MARK: - Types
+
 enum AppUpdateCheckInterval: String, CaseIterable, Identifiable {
     case hourly = "hourly"
     case daily = "daily"
@@ -1094,6 +1098,21 @@ final class AppUpdateManager: ObservableObject {
     }
 #endif
 
+#if !os(macOS)
+    private nonisolated static func readBundleShortVersionString(of appBundleURL: URL) -> String? {
+        let infoPlistURL = appBundleURL.appendingPathComponent("Info.plist")
+        guard
+            let data = try? Data(contentsOf: infoPlistURL),
+            let plist = try? PropertyListSerialization.propertyList(from: data, options: [], format: nil) as? [String: Any],
+            let version = plist["CFBundleShortVersionString"] as? String
+        else {
+            return nil
+        }
+        let trimmed = version.trimmingCharacters(in: .whitespacesAndNewlines)
+        return trimmed.isEmpty ? nil : trimmed
+    }
+#endif
+
     private func openURL(_ url: URL) {
 #if canImport(AppKit)
         NSWorkspace.shared.open(url)
diff --git a/Neon Vision Editor/Core/AppleFMHelper.swift b/Neon Vision Editor/Core/AppleFMHelper.swift
index 35a823d..2f9818f 100644
--- a/Neon Vision Editor/Core/AppleFMHelper.swift	
+++ b/Neon Vision Editor/Core/AppleFMHelper.swift	
@@ -3,6 +3,10 @@ import Foundation
 import FoundationModels
 
 @Generable(description: "Plain generated text")
+
+
+/// MARK: - Types
+
 public struct GeneratedText { public var text: String }
 
 public enum AppleFM {
diff --git a/Neon Vision Editor/Core/EditorPerformanceMonitor.swift b/Neon Vision Editor/Core/EditorPerformanceMonitor.swift
index d5a5abb..5acaee3 100644
--- a/Neon Vision Editor/Core/EditorPerformanceMonitor.swift	
+++ b/Neon Vision Editor/Core/EditorPerformanceMonitor.swift	
@@ -2,6 +2,10 @@ import Foundation
 import OSLog
 
 @MainActor
+
+
+/// MARK: - Types
+
 final class EditorPerformanceMonitor {
     struct FileOpenEvent: Codable, Identifiable {
         let id: UUID
diff --git a/Neon Vision Editor/Core/LanguageDetector.swift b/Neon Vision Editor/Core/LanguageDetector.swift
index 8cf1341..ad11432 100644
--- a/Neon Vision Editor/Core/LanguageDetector.swift	
+++ b/Neon Vision Editor/Core/LanguageDetector.swift	
@@ -1,5 +1,9 @@
 import Foundation
 
+
+
+/// MARK: - Types
+
 public struct LanguageDetector {
     public static let shared = LanguageDetector()
     private init() {}
diff --git a/Neon Vision Editor/Core/ReleaseRuntimePolicy.swift b/Neon Vision Editor/Core/ReleaseRuntimePolicy.swift
index 9f5d4fd..045db64 100644
--- a/Neon Vision Editor/Core/ReleaseRuntimePolicy.swift	
+++ b/Neon Vision Editor/Core/ReleaseRuntimePolicy.swift	
@@ -1,6 +1,10 @@
 import Foundation
 import SwiftUI
 
+
+
+/// MARK: - Types
+
 enum ReleaseRuntimePolicy {
     static var isUpdaterEnabledForCurrentDistribution: Bool {
 #if os(macOS)
diff --git a/Neon Vision Editor/Core/RuntimeReliabilityMonitor.swift b/Neon Vision Editor/Core/RuntimeReliabilityMonitor.swift
index a21efaa..bb447e6 100644
--- a/Neon Vision Editor/Core/RuntimeReliabilityMonitor.swift	
+++ b/Neon Vision Editor/Core/RuntimeReliabilityMonitor.swift	
@@ -2,6 +2,10 @@ import Foundation
 import OSLog
 
 @MainActor
+
+
+/// MARK: - Types
+
 final class RuntimeReliabilityMonitor {
     static let shared = RuntimeReliabilityMonitor()
 
diff --git a/Neon Vision Editor/Core/SyntaxHighlighting.swift b/Neon Vision Editor/Core/SyntaxHighlighting.swift
index 0efaf65..c75be97 100644
--- a/Neon Vision Editor/Core/SyntaxHighlighting.swift	
+++ b/Neon Vision Editor/Core/SyntaxHighlighting.swift	
@@ -1,6 +1,10 @@
 import SwiftUI
 import Foundation
 
+
+
+/// MARK: - Types
+
 private enum SyntaxRegexCache {
     static var storage: [String: NSRegularExpression] = [:]
     static let lock = NSLock()
diff --git a/Neon Vision Editor/Models/AIModel.swift b/Neon Vision Editor/Models/AIModel.swift
index 887aeb7..1d46dba 100644
--- a/Neon Vision Editor/Models/AIModel.swift	
+++ b/Neon Vision Editor/Models/AIModel.swift	
@@ -5,6 +5,10 @@
 
 import Foundation
 // Supported AI providers for suggestions. Extend as needed.
+
+
+/// MARK: - Types
+
 public enum AIModel: String, CaseIterable, Identifiable {
     case appleIntelligence
     case grok
diff --git a/Neon Vision Editor/UI/AIActivityLogView.swift b/Neon Vision Editor/UI/AIActivityLogView.swift
index b6fec09..34cbbd8 100644
--- a/Neon Vision Editor/UI/AIActivityLogView.swift	
+++ b/Neon Vision Editor/UI/AIActivityLogView.swift	
@@ -1,5 +1,9 @@
 import SwiftUI
 
+
+
+/// MARK: - Types
+
 struct AIActivityLogView: View {
     @State private var log = AIActivityLog.shared
 
diff --git a/Neon Vision Editor/UI/AppUpdaterDialog.swift b/Neon Vision Editor/UI/AppUpdaterDialog.swift
index a5a5ab8..7ee2ff6 100644
--- a/Neon Vision Editor/UI/AppUpdaterDialog.swift	
+++ b/Neon Vision Editor/UI/AppUpdaterDialog.swift	
@@ -1,5 +1,9 @@
 import SwiftUI
 
+
+
+/// MARK: - Types
+
 struct AppUpdaterDialog: View {
     @EnvironmentObject private var appUpdateManager: AppUpdateManager
     @Environment(\.accessibilityReduceTransparency) private var reduceTransparency
diff --git a/Neon Vision Editor/UI/ContentView+Actions.swift b/Neon Vision Editor/UI/ContentView+Actions.swift
index 810dc78..4d3ab45 100644
--- a/Neon Vision Editor/UI/ContentView+Actions.swift	
+++ b/Neon Vision Editor/UI/ContentView+Actions.swift	
@@ -6,6 +6,10 @@ import AppKit
 import UIKit
 #endif
 
+
+
+/// MARK: - Types
+
 extension ContentView {
     private struct ProjectEditorOverrides: Decodable {
         let indentWidth: Int?
@@ -629,9 +633,13 @@ extension ContentView {
     func applyWindowTranslucency(_ enabled: Bool) {
 #if os(macOS)
         for window in NSApp.windows {
+            // Apply only to editor windows registered by ContentView instances.
+            guard WindowViewModelRegistry.shared.viewModel(for: window.windowNumber) != nil else {
+                continue
+            }
             window.isOpaque = !enabled
             window.backgroundColor = enabled ? .clear : NSColor.windowBackgroundColor
-            // Keep window chrome layout stable across both modes to avoid frame/titlebar jumps.
+            // Keep chrome flags constant; toggling these causes visible top-bar jumps.
             window.titlebarAppearsTransparent = true
             window.toolbarStyle = .unified
             window.styleMask.insert(.fullSizeContentView)
@@ -760,7 +768,16 @@ extension ContentView {
             return []
         }
 
-        let sorted = urls.sorted { $0.lastPathComponent.localizedCaseInsensitiveCompare($1.lastPathComponent) == .orderedAscending }
+        let sorted = urls.sorted { lhs, rhs in
+            let lhsValues = try? lhs.resourceValues(forKeys: [.isDirectoryKey])
+            let rhsValues = try? rhs.resourceValues(forKeys: [.isDirectoryKey])
+            let lhsIsDirectory = lhsValues?.isDirectory == true
+            let rhsIsDirectory = rhsValues?.isDirectory == true
+            if lhsIsDirectory != rhsIsDirectory {
+                return lhsIsDirectory && !rhsIsDirectory
+            }
+            return lhs.lastPathComponent.localizedCaseInsensitiveCompare(rhs.lastPathComponent) == .orderedAscending
+        }
         var nodes: [ProjectTreeNode] = []
         for url in sorted {
             if Task.isCancelled { break }
diff --git a/Neon Vision Editor/UI/ContentView+Toolbar.swift b/Neon Vision Editor/UI/ContentView+Toolbar.swift
index 5b15b29..6384b69 100644
--- a/Neon Vision Editor/UI/ContentView+Toolbar.swift	
+++ b/Neon Vision Editor/UI/ContentView+Toolbar.swift	
@@ -5,6 +5,10 @@ import AppKit
 import UIKit
 #endif
 
+
+
+/// MARK: - Types
+
 extension ContentView {
     private var compactActiveProviderName: String {
         activeProviderName.components(separatedBy: " (").first ?? activeProviderName
diff --git a/Neon Vision Editor/UI/ContentView.swift b/Neon Vision Editor/UI/ContentView.swift
index 593de6b..02ccd9a 100644
--- a/Neon Vision Editor/UI/ContentView.swift	
+++ b/Neon Vision Editor/UI/ContentView.swift	
@@ -347,6 +347,9 @@ struct ContentView: View {
     @State private var recoverySnapshotIdentifier: String = UUID().uuidString
     @State private var lastCaretLocation: Int = 0
     @State private var sessionCaretByFileURL: [String: Int] = [:]
+#if os(macOS)
+    @State private var isProjectSidebarResizeHandleHovered: Bool = false
+#endif
     private let quickSwitcherRecentsDefaultsKey = "QuickSwitcherRecentItemsV1"
 
 #if USE_FOUNDATION_MODELS && canImport(FoundationModels)
@@ -3463,19 +3466,51 @@ struct ContentView: View {
             }
 
         return ZStack {
-            Color.clear
+            // Match the same surface as the editor area so the splitter doesn't look like a foreign strip.
             Rectangle()
-                .fill(Color.secondary.opacity(0.32))
+                .fill(projectSidebarHandleSurfaceStyle)
+            Rectangle()
+                .fill(Color.secondary.opacity(0.22))
                 .frame(width: 1)
         }
         .frame(width: 10)
         .contentShape(Rectangle())
         .gesture(drag)
+#if os(macOS)
+        .onHover { hovering in
+            guard hovering != isProjectSidebarResizeHandleHovered else { return }
+            isProjectSidebarResizeHandleHovered = hovering
+            if hovering {
+                NSCursor.resizeLeftRight.push()
+            } else {
+                NSCursor.pop()
+            }
+        }
+        .onDisappear {
+            if isProjectSidebarResizeHandleHovered {
+                isProjectSidebarResizeHandleHovered = false
+                NSCursor.pop()
+            }
+        }
+#endif
         .accessibilityElement()
         .accessibilityLabel("Resize Project Sidebar")
         .accessibilityHint("Drag left or right to adjust project sidebar width")
     }
 
+    private var projectSidebarHandleSurfaceStyle: AnyShapeStyle {
+        if enableTranslucentWindow {
+            return editorSurfaceBackgroundStyle
+        }
+#if os(iOS)
+        return useIOSUnifiedSolidSurfaces
+            ? AnyShapeStyle(iOSNonTranslucentSurfaceColor)
+            : AnyShapeStyle(Color.clear)
+#else
+        return AnyShapeStyle(Color.clear)
+#endif
+    }
+
     private var projectStructureSidebarBody: some View {
         ProjectStructureSidebarView(
             rootFolderURL: projectRootFolderURL,
@@ -3524,6 +3559,15 @@ struct ContentView: View {
         }
         .padding(.horizontal, 10)
         .padding(.vertical, 8)
+        .background(delimitedHeaderBackgroundColor)
+    }
+
+    private var delimitedHeaderBackgroundColor: Color {
+#if os(macOS)
+        Color(nsColor: .windowBackgroundColor)
+#else
+        Color(.systemBackground)
+#endif
     }
 
     private var delimitedTableView: some View {
diff --git a/Neon Vision Editor/UI/GlassSurface.swift b/Neon Vision Editor/UI/GlassSurface.swift
index 4ea8006..d81a38a 100644
--- a/Neon Vision Editor/UI/GlassSurface.swift	
+++ b/Neon Vision Editor/UI/GlassSurface.swift	
@@ -1,5 +1,9 @@
 import SwiftUI
 
+
+
+/// MARK: - Types
+
 enum GlassShapeKind {
     case capsule
     case circle
diff --git a/Neon Vision Editor/UI/IPadKeyboardShortcutBridge.swift b/Neon Vision Editor/UI/IPadKeyboardShortcutBridge.swift
index 56d24aa..9894dc1 100644
--- a/Neon Vision Editor/UI/IPadKeyboardShortcutBridge.swift	
+++ b/Neon Vision Editor/UI/IPadKeyboardShortcutBridge.swift	
@@ -2,6 +2,10 @@ import SwiftUI
 #if canImport(UIKit)
 import UIKit
 
+
+
+/// MARK: - Types
+
 struct IPadKeyboardShortcutBridge: UIViewRepresentable {
     let onNewTab: () -> Void
     let onOpenFile: () -> Void
diff --git a/Neon Vision Editor/UI/LineNumberRulerView.swift b/Neon Vision Editor/UI/LineNumberRulerView.swift
index 78cd4b3..a1e3fa7 100644
--- a/Neon Vision Editor/UI/LineNumberRulerView.swift	
+++ b/Neon Vision Editor/UI/LineNumberRulerView.swift	
@@ -1,6 +1,10 @@
 #if os(macOS)
 import AppKit
 
+
+
+/// MARK: - Types
+
 private struct RulerObserverToken: @unchecked Sendable {
     let raw: NSObjectProtocol
 }
diff --git a/Neon Vision Editor/UI/MarkdownPreviewWebView.swift b/Neon Vision Editor/UI/MarkdownPreviewWebView.swift
index 7a3caa0..d29ff7d 100644
--- a/Neon Vision Editor/UI/MarkdownPreviewWebView.swift	
+++ b/Neon Vision Editor/UI/MarkdownPreviewWebView.swift	
@@ -2,6 +2,10 @@ import SwiftUI
 import WebKit
 
 #if os(macOS)
+
+
+/// MARK: - Types
+
 struct MarkdownPreviewWebView: NSViewRepresentable {
     let html: String
 
diff --git a/Neon Vision Editor/UI/NeonSettingsView.swift b/Neon Vision Editor/UI/NeonSettingsView.swift
index 61e9d9f..acd5f24 100644
--- a/Neon Vision Editor/UI/NeonSettingsView.swift	
+++ b/Neon Vision Editor/UI/NeonSettingsView.swift	
@@ -9,6 +9,10 @@ import CoreText
 import UIKit
 #endif
 
+
+
+/// MARK: - Types
+
 struct NeonSettingsView: View {
     private static var cachedEditorFonts: [String] = []
     let supportsOpenInTabs: Bool
@@ -254,6 +258,7 @@ struct NeonSettingsView: View {
     var body: some View {
         settingsTabs
 #if os(macOS)
+        .background(settingsWindowBackground)
         .frame(
             minWidth: macSettingsWindowSize.min.width,
             idealWidth: macSettingsWindowSize.ideal.width,
@@ -264,14 +269,19 @@ struct NeonSettingsView: View {
             SettingsWindowConfigurator(
                 minSize: macSettingsWindowSize.min,
                 idealSize: macSettingsWindowSize.ideal,
-                translucentEnabled: supportsTranslucency && translucentWindow
+                translucentEnabled: supportsTranslucency && translucentWindow,
+                translucencyModeRaw: macTranslucencyModeRaw
             )
         )
 #endif
         .preferredColorScheme(preferredColorSchemeOverride)
         .onAppear {
-            settingsActiveTab = "general"
-            moreSectionTab = "support"
+            if settingsActiveTab.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
+                settingsActiveTab = "general"
+            }
+            if moreSectionTab.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
+                moreSectionTab = "support"
+            }
             selectedTheme = canonicalThemeName(selectedTheme)
             migrateLegacyPinkSettingsIfNeeded()
             loadAvailableEditorFontsIfNeeded()
@@ -2039,16 +2049,23 @@ struct NeonSettingsView: View {
     @ViewBuilder
     private var settingsContainerBackground: some View {
 #if os(macOS)
-        if supportsTranslucency && translucentWindow {
-            Color.clear.background(.ultraThinMaterial)
-        } else {
-            Color(nsColor: .windowBackgroundColor)
-        }
+        Color.clear
 #else
         Color.clear.background(.ultraThinMaterial)
 #endif
     }
 
+#if os(macOS)
+    @ViewBuilder
+    private var settingsWindowBackground: some View {
+        if supportsTranslucency && translucentWindow {
+            Color.clear
+        } else {
+            Color(nsColor: .windowBackgroundColor)
+        }
+    }
+#endif
+
     private func settingsEffectiveMaxWidth(base: CGFloat) -> CGFloat {
 #if os(iOS)
         if useTwoColumnSettingsLayout { return max(base, 780) }
@@ -2186,24 +2203,8 @@ struct NeonSettingsView: View {
     }
 
     private var macSettingsWindowSize: (min: NSSize, ideal: NSSize) {
-        switch settingsActiveTab {
-        case "themes":
-            return (NSSize(width: 740, height: 900), NSSize(width: 840, height: 980))
-        case "editor":
-            return (NSSize(width: 640, height: 820), NSSize(width: 720, height: 900))
-        case "templates":
-            return (NSSize(width: 600, height: 760), NSSize(width: 680, height: 840))
-        case "general":
-            return (NSSize(width: 600, height: 760), NSSize(width: 680, height: 840))
-        case "ai":
-            return (NSSize(width: 640, height: 780), NSSize(width: 720, height: 860))
-        case "updates":
-            return (NSSize(width: 580, height: 720), NSSize(width: 660, height: 780))
-        case "support":
-            return (NSSize(width: 580, height: 720), NSSize(width: 660, height: 780))
-        default:
-            return (NSSize(width: 600, height: 760), NSSize(width: 680, height: 840))
-        }
+        // Keep a stable window envelope across tabs to avoid toolbar-tab jump/overflow relayout.
+        (NSSize(width: 740, height: 900), NSSize(width: 840, height: 980))
     }
 #endif
 
@@ -2323,13 +2324,13 @@ struct SettingsWindowConfigurator: NSViewRepresentable {
     let minSize: NSSize
     let idealSize: NSSize
     let translucentEnabled: Bool
+    let translucencyModeRaw: String
 
     final class Coordinator {
         var didInitialApply = false
         var pendingApply: DispatchWorkItem?
-        var lastMinSize: NSSize?
-        var lastIdealSize: NSSize?
         var lastTranslucentEnabled: Bool?
+        var lastTranslucencyModeRaw: String?
         var didConfigureWindowChrome = false
     }
 
@@ -2350,13 +2351,11 @@ struct SettingsWindowConfigurator: NSViewRepresentable {
     }
 
     private func scheduleApply(to window: NSWindow?, coordinator: Coordinator) {
-        if coordinator.didInitialApply,
-           coordinator.lastMinSize == minSize,
-           coordinator.lastIdealSize == idealSize,
-           coordinator.lastTranslucentEnabled == translucentEnabled {
+        coordinator.pendingApply?.cancel()
+        if !coordinator.didInitialApply, let window {
+            apply(to: window, coordinator: coordinator)
             return
         }
-        coordinator.pendingApply?.cancel()
         let work = DispatchWorkItem {
             apply(to: window, coordinator: coordinator)
         }
@@ -2367,59 +2366,90 @@ struct SettingsWindowConfigurator: NSViewRepresentable {
     private func apply(to window: NSWindow?, coordinator: Coordinator) {
         guard let window else { return }
         let isFirstApply = !coordinator.didInitialApply
-        let translucencyChanged = coordinator.lastTranslucentEnabled != translucentEnabled
-        coordinator.lastMinSize = minSize
-        coordinator.lastIdealSize = idealSize
         coordinator.lastTranslucentEnabled = translucentEnabled
+        coordinator.lastTranslucencyModeRaw = translucencyModeRaw
         window.minSize = minSize
 
+        // Always enforce native macOS Settings toolbar chrome; other window updaters may have changed it.
+        window.toolbarStyle = .preference
+        window.titleVisibility = .hidden
+        window.title = ""
+        if isFirstApply {
+            let targetWidth = max(minSize.width, idealSize.width)
+            let targetHeight = max(minSize.height, idealSize.height)
+            if abs(targetWidth - window.frame.size.width) > 1 || abs(targetHeight - window.frame.size.height) > 1 {
+                // Apply initial geometry once; avoid frame churn during tab/content updates.
+                var frame = window.frame
+                let oldHeight = frame.size.height
+                frame.size = NSSize(width: targetWidth, height: targetHeight)
+                frame.origin.y += oldHeight - targetHeight
+                window.setFrame(frame, display: true, animate: false)
+            }
+            centerSettingsWindow(window)
+        }
+
         if !coordinator.didConfigureWindowChrome {
-            // Match native macOS Settings layout: centered preference tabs and hidden title text.
-            window.toolbarStyle = .preference
-            window.titleVisibility = .hidden
-            window.title = ""
+            // Keep settings chrome stable for the lifetime of this window.
+            window.isOpaque = false
+            window.titlebarAppearsTransparent = true
+            window.styleMask.insert(.fullSizeContentView)
+            if #available(macOS 13.0, *) {
+                window.titlebarSeparatorStyle = .none
+            }
             coordinator.didConfigureWindowChrome = true
         }
-
-        let targetWidth: CGFloat
-        let targetHeight: CGFloat
-        if coordinator.didInitialApply {
-            // Respect manual window size changes while enforcing per-tab minimums.
-            targetWidth = max(minSize.width, window.frame.size.width)
-            targetHeight = max(minSize.height, window.frame.size.height)
-        } else {
-            targetWidth = max(minSize.width, idealSize.width)
-            targetHeight = max(minSize.height, idealSize.height)
-        }
-        if abs(targetWidth - window.frame.size.width) > 1 || abs(targetHeight - window.frame.size.height) > 1 {
-            // Keep the top edge visually stable while adapting size per tab.
-            var frame = window.frame
-            let oldHeight = frame.size.height
-            frame.size = NSSize(width: targetWidth, height: targetHeight)
-            frame.origin.y += oldHeight - targetHeight
-            window.setFrame(frame, display: true, animate: false)
-        }
-
-        // Keep settings-window translucency in sync without relying on editor view events.
-        if translucencyChanged || isFirstApply {
-            window.isOpaque = !translucentEnabled
-            window.backgroundColor = translucentEnabled ? .clear : NSColor.windowBackgroundColor
-            window.titlebarAppearsTransparent = translucentEnabled
-            if translucentEnabled {
-                window.styleMask.insert(.fullSizeContentView)
-            } else {
-                window.styleMask.remove(.fullSizeContentView)
-            }
-            if #available(macOS 13.0, *) {
-                window.titlebarSeparatorStyle = translucentEnabled ? .none : .automatic
-            }
-        }
+        // Keep a non-clear background to avoid fully transparent titlebar artifacts.
+        window.backgroundColor = translucencyEnabledColor(enabled: translucentEnabled, window: window)
         // Some macOS states restore the title from the selected settings tab.
         // Force an empty, hidden title for native Settings appearance.
         window.title = ""
         window.titleVisibility = .hidden
+        window.representedURL = nil
         coordinator.didInitialApply = true
     }
+
+    private func translucencyEnabledColor(enabled: Bool, window: NSWindow) -> NSColor {
+        guard enabled else { return NSColor.windowBackgroundColor }
+        let isDark = window.effectiveAppearance.bestMatch(from: [.darkAqua, .aqua]) == .darkAqua
+        let whiteLevel: CGFloat
+        switch translucencyModeRaw {
+        case "subtle":
+            whiteLevel = isDark ? 0.18 : 0.90
+        case "vibrant":
+            whiteLevel = isDark ? 0.12 : 0.82
+        default:
+            whiteLevel = isDark ? 0.15 : 0.86
+        }
+        // Keep settings tint almost opaque to avoid "more transparent" appearance.
+        return NSColor(calibratedWhite: whiteLevel, alpha: 0.98)
+    }
+
+    private func centerSettingsWindow(_ settingsWindow: NSWindow) {
+        let referenceWindow = preferredReferenceWindow(excluding: settingsWindow)
+        let size = settingsWindow.frame.size
+        let referenceFrame = referenceWindow?.frame ?? settingsWindow.frame
+        var origin = NSPoint(
+            x: round(referenceFrame.midX - size.width / 2),
+            y: round(referenceFrame.midY - size.height / 2)
+        )
+        if let visibleFrame = referenceWindow?.screen?.visibleFrame ?? settingsWindow.screen?.visibleFrame {
+            origin.x = min(max(origin.x, visibleFrame.minX), visibleFrame.maxX - size.width)
+            origin.y = min(max(origin.y, visibleFrame.minY), visibleFrame.maxY - size.height)
+        }
+        settingsWindow.setFrameOrigin(origin)
+    }
+
+    private func preferredReferenceWindow(excluding settingsWindow: NSWindow) -> NSWindow? {
+        if let key = NSApp.keyWindow, key !== settingsWindow, key.isVisible {
+            return key
+        }
+        if let main = NSApp.mainWindow, main !== settingsWindow, main.isVisible {
+            return main
+        }
+        return NSApp.windows.first(where: { window in
+            window !== settingsWindow && window.isVisible && window.level == .normal
+        })
+    }
 }
 #endif
 
diff --git a/Neon Vision Editor/UI/PanelsAndHelpers.swift b/Neon Vision Editor/UI/PanelsAndHelpers.swift
index 1d9a1bb..a4ee632 100644
--- a/Neon Vision Editor/UI/PanelsAndHelpers.swift	
+++ b/Neon Vision Editor/UI/PanelsAndHelpers.swift	
@@ -5,6 +5,10 @@ import UniformTypeIdentifiers
 import AppKit
 #endif
 
+
+
+/// MARK: - Types
+
 enum NeonUIStyle {
     static let accentBlue = Color(red: 0.17, green: 0.49, blue: 0.98)
     static let accentBlueSoft = Color(red: 0.44, green: 0.72, blue: 0.99)
diff --git a/Neon Vision Editor/UI/ProjectFolderPicker.swift b/Neon Vision Editor/UI/ProjectFolderPicker.swift
index bd31461..ce772e4 100644
--- a/Neon Vision Editor/UI/ProjectFolderPicker.swift	
+++ b/Neon Vision Editor/UI/ProjectFolderPicker.swift	
@@ -3,6 +3,10 @@ import SwiftUI
 import UniformTypeIdentifiers
 import UIKit
 
+
+
+/// MARK: - Types
+
 struct ProjectFolderPicker: UIViewControllerRepresentable {
     let onPick: (URL) -> Void
     let onCancel: () -> Void
diff --git a/Neon Vision Editor/UI/SidebarViews.swift b/Neon Vision Editor/UI/SidebarViews.swift
index 81fa98c..319d24e 100644
--- a/Neon Vision Editor/UI/SidebarViews.swift	
+++ b/Neon Vision Editor/UI/SidebarViews.swift	
@@ -2,6 +2,10 @@ import SwiftUI
 import Foundation
 
 #if os(macOS)
+
+
+/// MARK: - Types
+
 private enum MacTranslucencyMode: String {
     case subtle
     case balanced
@@ -355,6 +359,18 @@ struct SidebarView: View {
     }
 }
 struct ProjectStructureSidebarView: View {
+    private enum SidebarDensity: String, CaseIterable, Identifiable {
+        case compact
+        case comfortable
+
+        var id: String { rawValue }
+    }
+
+    private struct FileIconStyle {
+        let symbol: String
+        let color: Color
+    }
+
     let rootFolderURL: URL?
     let nodes: [ProjectTreeNode]
     let selectedFileURL: URL?
@@ -370,6 +386,8 @@ struct ProjectStructureSidebarView: View {
 #if os(macOS)
     @AppStorage("SettingsMacTranslucencyMode") private var macTranslucencyModeRaw: String = "balanced"
 #endif
+    @AppStorage("SettingsProjectSidebarDensity") private var sidebarDensityRaw: String = SidebarDensity.compact.rawValue
+    @AppStorage("SettingsProjectSidebarAutoCollapseDeep") private var autoCollapseDeepFolders: Bool = true
 
     var body: some View {
         VStack(alignment: .leading, spacing: 0) {
@@ -405,6 +423,12 @@ struct ProjectStructureSidebarView: View {
                         )
                     }
                     Divider()
+                    Picker("Density", selection: $sidebarDensityRaw) {
+                        Text("Compact").tag(SidebarDensity.compact.rawValue)
+                        Text("Comfortable").tag(SidebarDensity.comfortable.rawValue)
+                    }
+                    Toggle("Auto-collapse Deep Folders", isOn: $autoCollapseDeepFolders)
+                    Divider()
                     Button("Expand All") {
                         expandAllDirectories()
                     }
@@ -419,20 +443,20 @@ struct ProjectStructureSidebarView: View {
                 .accessibilityLabel("Expand or collapse all folders")
                 .accessibilityHint("Expands or collapses all folders in the project tree")
             }
-            .padding(.horizontal, 10)
-            .padding(.top, 10)
-            .padding(.bottom, 8)
+            .padding(.horizontal, headerHorizontalPadding)
+            .padding(.top, headerTopPadding)
+            .padding(.bottom, headerBottomPadding)
 #if os(macOS)
             .background(sidebarHeaderFill)
 #endif
 
             if let rootFolderURL {
                 Text(rootFolderURL.path)
-                    .font(.caption2)
+                    .font(.system(size: isCompactDensity ? 11 : 12))
                     .foregroundStyle(.secondary)
-                    .lineLimit(2)
+                    .lineLimit(isCompactDensity ? 1 : 2)
                     .textSelection(.enabled)
-                    .padding(.horizontal, 10)
+                    .padding(.horizontal, headerHorizontalPadding)
             }
 
             List {
@@ -560,18 +584,21 @@ struct ProjectStructureSidebarView: View {
     }
 
     private func expandAllDirectories() {
-        expandedDirectories = allDirectoryNodeIDs(in: nodes)
+        expandedDirectories = allDirectoryNodeIDs(in: nodes, level: 0)
     }
 
     private func collapseAllDirectories() {
         expandedDirectories.removeAll()
     }
 
-    private func allDirectoryNodeIDs(in treeNodes: [ProjectTreeNode]) -> Set<String> {
+    private func allDirectoryNodeIDs(in treeNodes: [ProjectTreeNode], level: Int) -> Set<String> {
         var result: Set<String> = []
         for node in treeNodes where node.isDirectory {
-            result.insert(node.id)
-            result.formUnion(allDirectoryNodeIDs(in: node.children))
+            let shouldInclude = !autoCollapseDeepFolders || level < 2
+            if shouldInclude {
+                result.insert(node.id)
+            }
+            result.formUnion(allDirectoryNodeIDs(in: node.children, level: level + 1))
         }
         return result
     }
@@ -593,21 +620,30 @@ struct ProjectStructureSidebarView: View {
                         projectNodeView(child, level: level + 1)
                     }
                 } label: {
-                    Label(node.url.lastPathComponent, systemImage: "folder")
-                        .lineLimit(1)
+                    HStack(spacing: 8) {
+                        Image(systemName: "folder")
+                            .foregroundStyle(.blue)
+                            .symbolRenderingMode(.hierarchical)
+                        Text(node.url.lastPathComponent)
+                            .lineLimit(1)
+                    }
+                    .padding(.vertical, rowVerticalPadding)
                 }
-                .padding(.leading, CGFloat(level) * 10)
+                .padding(.leading, CGFloat(level) * levelIndent)
+                .listRowInsets(rowInsets)
                 .listRowBackground(Color.clear)
                 .listRowSeparator(.hidden)
             )
         } else {
+            let style = fileIconStyle(for: node.url)
             return AnyView(
                 Button {
                     onOpenProjectFile(node.url)
                 } label: {
                     HStack(spacing: 8) {
-                        Image(systemName: "doc.text")
-                            .foregroundColor(.secondary)
+                        Image(systemName: style.symbol)
+                            .foregroundStyle(style.color)
+                            .symbolRenderingMode(.hierarchical)
                         Text(node.url.lastPathComponent)
                             .lineLimit(1)
                         Spacer()
@@ -616,14 +652,100 @@ struct ProjectStructureSidebarView: View {
                                 .foregroundColor(.accentColor)
                         }
                     }
+                    .padding(.vertical, rowVerticalPadding)
                 }
                 .buttonStyle(.plain)
-                .padding(.leading, CGFloat(level) * 10)
+                .padding(.leading, CGFloat(level) * levelIndent)
+                .listRowInsets(rowInsets)
                 .listRowBackground(Color.clear)
                 .listRowSeparator(.hidden)
             )
         }
     }
+
+    private var sidebarDensity: SidebarDensity {
+        SidebarDensity(rawValue: sidebarDensityRaw) ?? .compact
+    }
+
+    private var isCompactDensity: Bool { sidebarDensity == .compact }
+
+    private var levelIndent: CGFloat {
+        isCompactDensity ? 8 : 12
+    }
+
+    private var rowVerticalPadding: CGFloat {
+        isCompactDensity ? 1 : 4
+    }
+
+    private var headerHorizontalPadding: CGFloat {
+        isCompactDensity ? 8 : 10
+    }
+
+    private var headerTopPadding: CGFloat {
+        isCompactDensity ? 8 : 10
+    }
+
+    private var headerBottomPadding: CGFloat {
+        isCompactDensity ? 6 : 8
+    }
+
+    private var rowInsets: EdgeInsets {
+        EdgeInsets(top: 0, leading: isCompactDensity ? 4 : 6, bottom: 0, trailing: 4)
+    }
+
+    private func fileIconStyle(for url: URL) -> FileIconStyle {
+        let ext = url.pathExtension.lowercased()
+        let name = url.lastPathComponent.lowercased()
+
+        switch ext {
+        case "swift":
+            return .init(symbol: "swift", color: .orange)
+        case "js", "mjs", "cjs":
+            return .init(symbol: "curlybraces.square", color: .yellow)
+        case "ts", "tsx":
+            return .init(symbol: "chevron.left.forwardslash.chevron.right", color: .blue)
+        case "json", "jsonc", "json5":
+            return .init(symbol: "curlybraces", color: .green)
+        case "md", "markdown":
+            return .init(symbol: "text.alignleft", color: .teal)
+        case "yml", "yaml", "toml", "ini", "env":
+            return .init(symbol: "slider.horizontal.3", color: .mint)
+        case "html", "htm":
+            return .init(symbol: "chevron.left.slash.chevron.right", color: .orange)
+        case "css":
+            return .init(symbol: "paintbrush.pointed", color: .cyan)
+        case "xml", "svg":
+            return .init(symbol: "diamond", color: .pink)
+        case "sh", "bash", "zsh", "ps1":
+            return .init(symbol: "terminal", color: .indigo)
+        case "py":
+            return .init(symbol: "chevron.left.forwardslash.chevron.right", color: .yellow)
+        case "rb":
+            return .init(symbol: "diamond.fill", color: .red)
+        case "go":
+            return .init(symbol: "g.circle", color: .cyan)
+        case "rs":
+            return .init(symbol: "gearshape.2", color: .orange)
+        case "sql":
+            return .init(symbol: "cylinder", color: .purple)
+        case "csv", "tsv":
+            return .init(symbol: "tablecells", color: .green)
+        case "txt", "log":
+            return .init(symbol: "doc.plaintext", color: .secondary)
+        case "png", "jpg", "jpeg", "gif", "webp", "heic":
+            return .init(symbol: "photo", color: .purple)
+        case "pdf":
+            return .init(symbol: "doc.richtext", color: .red)
+        default:
+            if name.hasPrefix(".git") {
+                return .init(symbol: "arrow.triangle.branch", color: .orange)
+            }
+            if name.hasPrefix(".env") {
+                return .init(symbol: "lock.doc", color: .mint)
+            }
+            return .init(symbol: "doc.text", color: .secondary)
+        }
+    }
 }
 
 struct ProjectTreeNode: Identifiable {
diff --git a/Neon Vision EditorTests/AppUpdateManagerTests.swift b/Neon Vision EditorTests/AppUpdateManagerTests.swift
index d8db6b9..674d1b6 100644
--- a/Neon Vision EditorTests/AppUpdateManagerTests.swift	
+++ b/Neon Vision EditorTests/AppUpdateManagerTests.swift	
@@ -1,6 +1,10 @@
 import XCTest
 @testable import Neon_Vision_Editor
 
+
+
+/// MARK: - Tests
+
 final class AppUpdateManagerTests: XCTestCase {
     func testHostAllowlistBehavior() {
         XCTAssertTrue(AppUpdateManager.isTrustedGitHubHost("github.com"))
diff --git a/Neon Vision EditorTests/LanguageDetectorTests.swift b/Neon Vision EditorTests/LanguageDetectorTests.swift
index 0763336..9117c82 100644
--- a/Neon Vision EditorTests/LanguageDetectorTests.swift	
+++ b/Neon Vision EditorTests/LanguageDetectorTests.swift	
@@ -1,5 +1,9 @@
 import XCTest
 
+
+
+/// MARK: - Tests
+
 final class LanguageDetectorTests: XCTestCase {
     func testPreferredLanguageForExtensions() {
         let cases: [(String, String)] = [
diff --git a/Neon Vision EditorTests/MarkdownSyntaxHighlightingTests.swift b/Neon Vision EditorTests/MarkdownSyntaxHighlightingTests.swift
index 1ef76f0..1dd5961 100644
--- a/Neon Vision EditorTests/MarkdownSyntaxHighlightingTests.swift	
+++ b/Neon Vision EditorTests/MarkdownSyntaxHighlightingTests.swift	
@@ -2,6 +2,10 @@ import XCTest
 import SwiftUI
 @testable import Neon_Vision_Editor
 
+
+
+/// MARK: - Tests
+
 final class MarkdownSyntaxHighlightingTests: XCTestCase {
     private func markdownPatterns() -> [String: Color] {
         getSyntaxPatterns(
diff --git a/Neon Vision EditorTests/ReleaseRuntimePolicyTests.swift b/Neon Vision EditorTests/ReleaseRuntimePolicyTests.swift
index 0f74add..a4e4d43 100644
--- a/Neon Vision EditorTests/ReleaseRuntimePolicyTests.swift	
+++ b/Neon Vision EditorTests/ReleaseRuntimePolicyTests.swift	
@@ -2,6 +2,10 @@ import XCTest
 import SwiftUI
 @testable import Neon_Vision_Editor
 
+
+
+/// MARK: - Tests
+
 final class ReleaseRuntimePolicyTests: XCTestCase {
     func testSettingsTabFallsBackToGeneral() {
         XCTAssertEqual(ReleaseRuntimePolicy.settingsTab(from: nil), "general")
diff --git a/Neon Vision EditorTests/WindowTranslucencyTests.swift b/Neon Vision EditorTests/WindowTranslucencyTests.swift
index f9846be..0380a30 100644
--- a/Neon Vision EditorTests/WindowTranslucencyTests.swift	
+++ b/Neon Vision EditorTests/WindowTranslucencyTests.swift	
@@ -5,6 +5,10 @@ import XCTest
 import AppKit
 
 @MainActor
+
+
+/// MARK: - Tests
+
 final class WindowTranslucencyTests: XCTestCase {
     // Verifies that the translucency toggle updates AppKit window flags used by the toolbar/titlebar.
     func testApplyWindowTranslucencyUpdatesMacWindowFlags() {