Added preview device. Added layout margins padding.

Sources/SwiftUIExtension/Extensions/PreviewDevice.swift

@@ -0,0 +1,8 @@
+import SwiftUI
+
+extension PreviewDevice {
+
+    public static var visionPro: PreviewDevice {
+        PreviewDevice(rawValue: "Apple Vision Pro")
+    }
+}

Sources/SwiftUIExtension/Extensions/ViewExtension+LayoutMargins.swift

@@ -0,0 +1,46 @@
+import SwiftUI
+
+extension View {
+
+    public func horizontalSystemPadding() -> some View {
+        modifier(HorizontalSystemPadding())
+    }
+}
+
+struct HorizontalSystemPadding: ViewModifier {
+
+    var value: CGFloat {
+        switch horizontalSizeClass {
+        case .compact:
+            return 16
+        case .regular:
+            #if os(visionOS)
+            return 24
+            #else
+            return 20
+            #endif
+        default:
+            return 16
+        }
+    }
+
+    //var withCompensation: Bool = false
+
+    @Environment(\.horizontalSizeClass) var horizontalSizeClass
+
+    public func body(content: Content) -> some View {
+        /*let compensation: CGFloat = {
+            #if os(visionOS)
+            return -14
+            #else
+            return .zero
+            #endif
+        }()*/
+        if #available(iOS 17.0, macOS 14.0, *) {
+            content
+                .contentMargins(.horizontal, value, for: .scrollContent)
+        } else {
+            content
+        }
+    }
+}