diff --git a/Sources/OpenSwiftUICore/Data/Environment/AppearsActive.swift b/Sources/OpenSwiftUICore/Data/Environment/AppearsActive.swift
new file mode 100644
index 000000000..bdfa62243
--- /dev/null
+++ b/Sources/OpenSwiftUICore/Data/Environment/AppearsActive.swift
@@ -0,0 +1,67 @@
+//
+//  AppearsActive.swift
+//  OpenSwiftUICore
+//
+//  Audited for 6.5.4
+//  Status: Complete
+
+// MARK: - AppearsActiveKey
+
+/// Whether views and styles in this environment should prefer an active
+/// appearance over an inactive appearance.
+@available(OpenSwiftUI_v6_0, *)
+@usableFromInline
+package struct AppearsActiveKey: EnvironmentKey {
+    @usableFromInline
+    package static var defaultValue: Bool { true }
+}
+
+@available(*, unavailable)
+extension AppearsActiveKey: Sendable {}
+
+@available(OpenSwiftUI_v6_0, *)
+extension EnvironmentValues {
+
+    /// Whether views and styles in this environment should prefer an active
+    /// appearance over an inactive appearance.
+    ///
+    /// On macOS, views in the focused window (also referred to as the "key"
+    /// window) should appear active. Some contexts also appear active in other
+    /// circumstances, such as the contents of a window toolbar appearing active
+    /// when the window is not focused but is the main window.
+    ///
+    /// Typical adjustments made when a view does not appear active include:
+    /// - Uses of `Color.accentColor` should generally be removed or replaced
+    ///   with a desaturated style.
+    /// - Text and image content in sidebars should appear dimmer.
+    /// - Buttons with destructive actions should appear disabled.
+    /// - `ShapeStyle.selection` and selection in list and tables will
+    ///   automatically become a grey color
+    ///
+    /// Custom views, styles, and shape styles can use this to adjust their
+    /// own appearance:
+    ///
+    ///     struct ProminentPillButtonStyle: ButtonStyle {
+    ///         @Environment(\.appearsActive) private var appearsActive
+    ///
+    ///         func makeBody(configuration: Configuration) -> some View {
+    ///             configuration.label
+    ///                 .lineLimit(1)
+    ///                 .padding(.horizontal, 8)
+    ///                 .padding(.vertical, 2)
+    ///                 .frame(minHeight: 20)
+    ///                 .overlay(Capsule().strokeBorder(.tertiary))
+    ///                 .background(appearsActive ? Color.accentColor : .clear, in: .capsule)
+    ///                 .contentShape(.capsule)
+    ///         }
+    ///     }
+    ///
+    /// On all other platforms, this value is always `true`.
+    ///
+    /// This is bridged with `UITraitCollection.activeAppearance` for UIKit
+    /// hosted content.
+    public var appearsActive: Bool {
+        get { self[AppearsActiveKey.self] }
+        set { self[AppearsActiveKey.self] = newValue }
+    }
+}
diff --git a/Sources/OpenSwiftUICore/Data/Environment/EnvironmentAdditions.swift b/Sources/OpenSwiftUICore/Data/Environment/EnvironmentAdditions.swift
index 0267613bf..a9ec24110 100644
--- a/Sources/OpenSwiftUICore/Data/Environment/EnvironmentAdditions.swift
+++ b/Sources/OpenSwiftUICore/Data/Environment/EnvironmentAdditions.swift
@@ -3,7 +3,7 @@
 //  OpenSwiftUICore
 //
 //  Audited for 6.5.4
-//  Status: Blocked by controlActiveState
+//  Status: Complete
 //  ID: 1B17C64D9E901A0054B49B69A4A2439D (SwiftUICore)
 
 public import Foundation
@@ -829,8 +829,8 @@ extension EnvironmentValues {
     @available(watchOS, unavailable)
     @available(visionOS, unavailable)
     public var controlActiveState: ControlActiveState {
-        get { _openSwiftUIUnimplementedFailure() }
-        set { _openSwiftUIUnimplementedFailure() }
+        get { appearsActive ? .key : .inactive }
+        set { appearsActive = (newValue == .key || newValue == .active) }
     }
 
     /// The horizontal size class of this environment.
diff --git a/Sources/OpenSwiftUICore/Data/Environment/WindowEnvironment.swift b/Sources/OpenSwiftUICore/Data/Environment/WindowEnvironment.swift
new file mode 100644
index 000000000..c3b9bc77c
--- /dev/null
+++ b/Sources/OpenSwiftUICore/Data/Environment/WindowEnvironment.swift
@@ -0,0 +1,64 @@
+//
+//  WindowEnvironment.swift
+//  OpenSwiftUICore
+//
+//  Audited for 6.5.4
+//  Status: Complete
+
+// MARK: - WindowEnvironmentKeys
+
+package enum WindowEnvironmentKeys {
+
+    package struct AppearsFocused: EnvironmentKey {
+        package static var defaultValue: Bool { true }
+    }
+
+    package struct AppearsMain: EnvironmentKey {
+        package static var defaultValue: Bool { false }
+    }
+
+    package struct AppearsActive: EnvironmentKey {
+        package static var defaultValue: Bool { true }
+    }
+
+    package struct IsFocused: EnvironmentKey {
+        package static var defaultValue: Bool { true }
+    }
+
+    package struct IsMain: EnvironmentKey {
+        package static var defaultValue: Bool { true }
+    }
+}
+
+// MARK: - EnvironmentValues + WindowEnvironmentKeys
+
+@_spi(ForOpenSwiftUIOnly)
+@_spi(DoNotImport)
+@available(OpenSwiftUI_v6_0, *)
+extension EnvironmentValues {
+
+    public var windowAppearsFocused: Bool {
+        get { self[WindowEnvironmentKeys.AppearsFocused.self] }
+        set { self[WindowEnvironmentKeys.AppearsFocused.self] = newValue }
+    }
+
+    public var windowAppearsMain: Bool {
+        get { self[WindowEnvironmentKeys.AppearsMain.self] }
+        set { self[WindowEnvironmentKeys.AppearsMain.self] = newValue }
+    }
+
+    public var windowAppearsActive: Bool {
+        get { self[WindowEnvironmentKeys.AppearsActive.self] }
+        set { self[WindowEnvironmentKeys.AppearsActive.self] = newValue }
+    }
+
+    public var windowIsFocused: Bool {
+        get { self[WindowEnvironmentKeys.IsFocused.self] }
+        set { self[WindowEnvironmentKeys.IsFocused.self] = newValue }
+    }
+
+    public var windowIsMain: Bool {
+        get { self[WindowEnvironmentKeys.IsMain.self] }
+        set { self[WindowEnvironmentKeys.IsMain.self] = newValue }
+    }
+}