diff --git a/src/ClaudeDo.Ui/Views/MainWindow.axaml b/src/ClaudeDo.Ui/Views/MainWindow.axaml
index ff3e56f..1d6d5d4 100644
--- a/src/ClaudeDo.Ui/Views/MainWindow.axaml
+++ b/src/ClaudeDo.Ui/Views/MainWindow.axaml
@@ -141,15 +141,42 @@
       </Border.Background>
     </Border>
 
-    <!-- Three islands -->
-    <Grid Grid.Row="2" Margin="7" ColumnDefinitions="260,*,320">
+    <!-- Three islands (user-resizable) -->
+    <Grid Grid.Row="2" Margin="7">
+      <Grid.ColumnDefinitions>
+        <ColumnDefinition Width="260" MinWidth="200"/>
+        <ColumnDefinition Width="Auto"/>
+        <ColumnDefinition Width="*" MinWidth="320"/>
+        <ColumnDefinition Width="Auto"/>
+        <ColumnDefinition Width="320" MinWidth="280"/>
+      </Grid.ColumnDefinitions>
+
       <Border Grid.Column="0" Classes="island" Margin="7">
         <islands:ListsIslandView DataContext="{Binding Lists}"/>
       </Border>
-      <Border Grid.Column="1" Classes="island" Margin="7">
+
+      <GridSplitter Grid.Column="1"
+                    Width="3"
+                    Background="Transparent"
+                    HorizontalAlignment="Stretch"
+                    VerticalAlignment="Stretch"
+                    ResizeDirection="Columns"
+                    ResizeBehavior="PreviousAndNext"/>
+
+      <Border Grid.Column="2" Classes="island" Margin="7">
         <islands:TasksIslandView DataContext="{Binding Tasks}"/>
       </Border>
-      <Border Grid.Column="2" Classes="island" Margin="7"
+
+      <GridSplitter Grid.Column="3"
+                    Width="3"
+                    Background="Transparent"
+                    HorizontalAlignment="Stretch"
+                    VerticalAlignment="Stretch"
+                    ResizeDirection="Columns"
+                    ResizeBehavior="PreviousAndNext"
+                    IsVisible="{Binding ShowDetails}"/>
+
+      <Border Grid.Column="4" Classes="island" Margin="7"
               IsVisible="{Binding ShowDetails}">
         <islands:DetailsIslandView DataContext="{Binding Details}"/>
       </Border>