diff --git a/Pixiview.iOS/Pixiview.iOS.csproj b/Pixiview.iOS/Pixiview.iOS.csproj
index 58f3b6b..872ce70 100644
--- a/Pixiview.iOS/Pixiview.iOS.csproj
+++ b/Pixiview.iOS/Pixiview.iOS.csproj
@@ -61,6 +61,7 @@
     <MtouchArch>ARM64</MtouchArch>
     <CodesignKey>iPhone Developer</CodesignKey>
     <CodesignEntitlements>Entitlements.plist</CodesignEntitlements>
+    <MtouchUseLlvm>true</MtouchUseLlvm>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="Main.cs" />
diff --git a/Pixiview/Illust/IllustCollectionPage.cs b/Pixiview/Illust/IllustCollectionPage.cs
index 4085584..09453ed 100644
--- a/Pixiview/Illust/IllustCollectionPage.cs
+++ b/Pixiview/Illust/IllustCollectionPage.cs
@@ -58,8 +58,6 @@ namespace Pixiview.Illust
         public IllustCollection IllustCollection { get; set; }
 
         protected virtual bool IsFavoriteVisible => true;
-        protected Thickness totalBarOffset;
-        protected Thickness navigationBarOffset;
         protected bool loaded;
 
         private T illustData;
@@ -123,30 +121,15 @@ namespace Pixiview.Illust
             }
         }
 
-        public override void OnOrientationChanged(Orientation orientation)
+        protected override void OnSizeAllocated(double width, double height)
         {
-            int columns;
-            switch (orientation)
-            {
-                case Orientation.Portrait:
-                    columns = 2;
-                    break;
-                case Orientation.PortraitUpsideDown:
-                    columns = isPhone ? 4 : 2;
-                    break;
-                case Orientation.Unknown:
-                case Orientation.LandscapeLeft:
-                case Orientation.LandscapeRight:
-                default:
-                    columns = 4;
-                    break;
-            }
+            base.OnSizeAllocated(width, height);
+            var columns = width > height ? 4 : 2;
             if (Columns != columns)
             {
-                App.DebugPrint($"change columns to {columns}");
                 Columns = columns;
+                App.DebugPrint($"change columns to {columns}");
             }
-            base.OnOrientationChanged(orientation);
         }
 
         #endregion
diff --git a/Pixiview/Illust/RankingPage.xaml.cs b/Pixiview/Illust/RankingPage.xaml.cs
index fb3d9fa..cc2b849 100644
--- a/Pixiview/Illust/RankingPage.xaml.cs
+++ b/Pixiview/Illust/RankingPage.xaml.cs
@@ -21,39 +21,29 @@ namespace Pixiview.Illust
 
         public RankingPage()
         {
-            totalBarOffset = new Thickness(0, AppShell.TotalBarOffset.Top + 50, 0, 0);
-            navigationBarOffset = new Thickness(0, AppShell.NavigationBarOffset.Top + 50, 0, 0);
-
             Resources.Add("cardView", GetCardViewTemplate());
             InitializeComponent();
         }
 
         public override void OnOrientationChanged(Orientation orientation)
         {
-            int columns;
             switch (orientation)
             {
                 case Orientation.Portrait:
-                    columns = 2;
-                    PageTopMargin = totalBarOffset;
+                    PageTopMargin = new Thickness(0, AppShell.TotalBarOffset.Top + 50, 0, 0);
                     break;
                 case Orientation.PortraitUpsideDown:
-                    columns = isPhone ? 4 : 2;
-                    PageTopMargin = isPhone ? navigationBarOffset : totalBarOffset;
+                    PageTopMargin = isPhone ?
+                        new Thickness(0, AppShell.NavigationBarOffset.Top + 50, 0, 0) :
+                        new Thickness(0, AppShell.TotalBarOffset.Top + 50, 0, 0);
                     break;
                 case Orientation.Unknown:
                 case Orientation.LandscapeLeft:
                 case Orientation.LandscapeRight:
                 default:
-                    columns = 4;
-                    PageTopMargin = navigationBarOffset;
+                    PageTopMargin = new Thickness(0, AppShell.NavigationBarOffset.Top + 50, 0, 0);
                     break;
             }
-            if (Columns != columns)
-            {
-                App.DebugPrint($"ranking page, change columns to {columns}");
-                Columns = columns;
-            }
         }
 
         protected override IEnumerable<IllustItem> DoGetIllustList(IllustData data, ICommand command)
diff --git a/Pixiview/Illust/RecommendsPage.xaml.cs b/Pixiview/Illust/RecommendsPage.xaml.cs
index cff8e96..c45ad67 100644
--- a/Pixiview/Illust/RecommendsPage.xaml.cs
+++ b/Pixiview/Illust/RecommendsPage.xaml.cs
@@ -28,39 +28,29 @@ namespace Pixiview.Illust
 
         public RecommendsPage()
         {
-            totalBarOffset = new Thickness(0, AppShell.TotalBarOffset.Top + 40, 0, 0);
-            navigationBarOffset = new Thickness(0, AppShell.NavigationBarOffset.Top + 40, 0, 0);
-
             Resources.Add("cardView", GetCardViewTemplate());
             InitializeComponent();
         }
 
         public override void OnOrientationChanged(Orientation orientation)
         {
-            int columns;
             switch (orientation)
             {
                 case Orientation.Portrait:
-                    columns = 2;
-                    PageTopMargin = totalBarOffset;
+                    PageTopMargin = new Thickness(0, AppShell.TotalBarOffset.Top + 40, 0, 0);
                     break;
                 case Orientation.PortraitUpsideDown:
-                    columns = isPhone ? 4 : 2;
-                    PageTopMargin = isPhone ? navigationBarOffset : totalBarOffset;
+                    PageTopMargin = isPhone ?
+                        new Thickness(0, AppShell.NavigationBarOffset.Top + 40, 0, 0) :
+                        new Thickness(0, AppShell.TotalBarOffset.Top + 40, 0, 0);
                     break;
                 case Orientation.Unknown:
                 case Orientation.LandscapeLeft:
                 case Orientation.LandscapeRight:
                 default:
-                    columns = 4;
-                    PageTopMargin = navigationBarOffset;
+                    PageTopMargin = new Thickness(0, AppShell.NavigationBarOffset.Top + 40, 0, 0);
                     break;
             }
-            if (Columns != columns)
-            {
-                App.DebugPrint($"ranking page, change columns to {columns}");
-                Columns = columns;
-            }
         }
 
         protected override IEnumerable<IllustItem> DoGetIllustList(IllustData data, ICommand command)