diff --git a/Packages/ZettelKit/Package.swift b/Packages/ZettelKit/Package.swift
index 8fb411f..58243cb 100644
--- a/Packages/ZettelKit/Package.swift
+++ b/Packages/ZettelKit/Package.swift
@@ -5,7 +5,7 @@ import PackageDescription
 let package = Package(
     name: "ZettelKit",
     platforms: [
-        .macOS(.v26),
+        .macOS(.v15),
         .iOS(.v26)
     ],
     products: [
diff --git a/Zettel.xcodeproj/project.pbxproj b/Zettel.xcodeproj/project.pbxproj
index cc548db..f66457d 100644
--- a/Zettel.xcodeproj/project.pbxproj
+++ b/Zettel.xcodeproj/project.pbxproj
@@ -254,7 +254,7 @@
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 				);
-				MACOSX_DEPLOYMENT_TARGET = 26.0;
+				MACOSX_DEPLOYMENT_TARGET = 15.0;
 				MARKETING_VERSION = 1.2;
 				ONLY_ACTIVE_ARCH = YES;
 				PRODUCT_BUNDLE_IDENTIFIER = "";
@@ -496,7 +496,7 @@
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 				);
-				MACOSX_DEPLOYMENT_TARGET = 26.0;
+				MACOSX_DEPLOYMENT_TARGET = 15.0;
 				MARKETING_VERSION = 1.2;
 				PRODUCT_BUNDLE_IDENTIFIER = "";
 				PRODUCT_NAME = Zettel;
diff --git a/ZettelMac/Info.plist b/ZettelMac/Info.plist
index 7203bbf..83e786c 100644
--- a/ZettelMac/Info.plist
+++ b/ZettelMac/Info.plist
@@ -24,7 +24,7 @@
 		</dict>
 	</array>
 	<key>LSMinimumSystemVersion</key>
-	<string>26.0</string>
+	<string>15.0</string>
 	<key>ITSAppUsesNonExemptEncryption</key>
 	<false/>
 </dict>
diff --git a/ZettelMac/Preferences/MacDockIconPreference.swift b/ZettelMac/Preferences/MacDockIconPreference.swift
index 267db5a..aba6d03 100644
--- a/ZettelMac/Preferences/MacDockIconPreference.swift
+++ b/ZettelMac/Preferences/MacDockIconPreference.swift
@@ -36,7 +36,7 @@ enum MacDockIconPreference {
         let activationPolicy: NSApplication.ActivationPolicy = shouldHide ? .accessory : .regular
         let didSet = NSApplication.shared.setActivationPolicy(activationPolicy)
         if !didSet {
-            let currentIsHidden = NSApplication.shared.activationPolicy == .accessory
+            let currentIsHidden = NSApplication.shared.activationPolicy() == .accessory
             UserDefaults.standard.set(currentIsHidden, forKey: storageKey)
         }
     }
diff --git a/ZettelMac/Views/TagAutocompletePanel.swift b/ZettelMac/Views/TagAutocompletePanel.swift
index 9dde9e9..a541edf 100644
--- a/ZettelMac/Views/TagAutocompletePanel.swift
+++ b/ZettelMac/Views/TagAutocompletePanel.swift
@@ -99,7 +99,7 @@ struct TagSuggestionsView: View {
             }
         }
         .padding(.vertical, 4)
-        .glassEffect(in: .rect(cornerRadius: 10))
+        .modifier(GlassEffectFallback(cornerRadius: 10))
         // No SwiftUI shadow — NSHostingView clips it to a hard rect.
         // p.hasShadow = true on the NSPanel gives the correct shaped shadow.
     }
@@ -157,6 +157,21 @@ private struct TagSuggestionRow: View {
     }
 }
 
+// MARK: - Glass Effect Fallback
+
+/// Applies `.glassEffect` on macOS 26+, falls back to `.background(.ultraThinMaterial)` on earlier versions.
+private struct GlassEffectFallback: ViewModifier {
+    let cornerRadius: CGFloat
+
+    func body(content: Content) -> some View {
+        if #available(macOS 26, *) {
+            content.glassEffect(in: .rect(cornerRadius: cornerRadius))
+        } else {
+            content.background(.ultraThinMaterial, in: .rect(cornerRadius: cornerRadius))
+        }
+    }
+}
+
 // MARK: - Controller
 
 /// Manages the floating `NSPanel` that hosts `TagSuggestionsView`.
diff --git a/ZettelMac/Window/ZettelWindowManager.swift b/ZettelMac/Window/ZettelWindowManager.swift
index b9efd58..48be4e7 100644
--- a/ZettelMac/Window/ZettelWindowManager.swift
+++ b/ZettelMac/Window/ZettelWindowManager.swift
@@ -215,9 +215,11 @@ final class ZettelWindowManager: NSObject, ObservableObject {
         panel.titlebarAppearsTransparent = true
         panel.titleVisibility = .hidden
 
-        // Transparent background for Liquid Glass
-        panel.isOpaque = false
-        panel.backgroundColor = .clear
+        // Transparent background for Liquid Glass (macOS 26+)
+        if #available(macOS 26, *) {
+            panel.isOpaque = false
+            panel.backgroundColor = .clear
+        }
 
         // Set min size
         panel.minSize = NSSize(width: 420, height: 380)