Refine settings/about titlebar styling and controls alignment

Sources/WindowDecorationsController.swift

@@ -3,6 +3,7 @@ import AppKit
 final class WindowDecorationsController {
     private var observers: [NSObjectProtocol] = []
     private var didStart = false
+    private var trafficLightBaseFrames: [ObjectIdentifier: [NSWindow.ButtonType: NSRect]] = [:]
 
     func start() {
         guard !didStart else { return }
@@ -14,6 +15,7 @@ final class WindowDecorationsController {
     func apply(to window: NSWindow) {
         let shouldHideButtons = shouldHideTrafficLights(for: window)
         hideStandardButtons(on: window, hidden: shouldHideButtons)
+        applyTrafficLightOffset(on: window, hidden: shouldHideButtons)
     }
 
     private func installObservers() {
@@ -38,6 +40,40 @@ final class WindowDecorationsController {
         window.standardWindowButton(.zoomButton)?.isHidden = hidden
     }
 
+    private func applyTrafficLightOffset(on window: NSWindow, hidden: Bool) {
+        DispatchQueue.main.async { [weak self, weak window] in
+            guard let self, let window else { return }
+            let offset = hidden ? NSPoint.zero : self.trafficLightOffset(for: window)
+            self.applyTrafficLightOffsetNow(on: window, offset: offset)
+        }
+    }
+
+    private func applyTrafficLightOffsetNow(on window: NSWindow, offset: NSPoint) {
+        let key = ObjectIdentifier(window)
+        let buttonTypes: [NSWindow.ButtonType] = [.closeButton, .miniaturizeButton, .zoomButton]
+        var baseFrames = trafficLightBaseFrames[key] ?? [:]
+
+        for type in buttonTypes {
+            guard let button = window.standardWindowButton(type) else { continue }
+            if baseFrames[type] == nil || (baseFrames[type]?.isEmpty ?? true) {
+                baseFrames[type] = button.frame
+            }
+        }
+
+        trafficLightBaseFrames[key] = baseFrames
+
+        for type in buttonTypes {
+            guard let button = window.standardWindowButton(type), let base = baseFrames[type] else { continue }
+            button.setFrameOrigin(NSPoint(x: base.origin.x + offset.x, y: base.origin.y + offset.y))
+        }
+    }
+
+    private func trafficLightOffset(for window: NSWindow) -> NSPoint {
+        guard window.identifier?.rawValue == "cmux.settings" else { return .zero }
+        // Nudge controls slightly right/down to align with the custom Settings title row.
+        return NSPoint(x: 7, y: -4)
+    }
+
     private func shouldHideTrafficLights(for window: NSWindow) -> Bool {
         if window.isSheet {
             return true