こうかな <Style TargetType="TabItem"> <Setter Property="Foreground" Value="#cfd5dc" /> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="TabItem"> <Border Name="Border" BorderThickness="1,1,1,0" BorderBrush="Gainsboro" CornerRadius="4,4,0,0" Margin="2,0"> </border></controltemplate></setter.value></setter></setter>