WPF TabControl style crashes when attaching colors as DynamicResource

I am trying to apply a azure-like style to my WPF TabControl as explained here.

I want to achieve this look and feel:

<UserControl.Resources>
  <ResourceDictionary>

    <SolidColorBrush x:Key="AccentColorBrush" Color="CornflowerBlue" />
    <SolidColorBrush x:Key="BlackColor" Color="Black" />
    <SolidColorBrush x:Key="WhiteColor" Color="White" />
    <SolidColorBrush x:Key="Gray5" Color="LightGray" />

    <Style x:Key="AzureTabItem" TargetType="{x:Type TabItem}">
        <Setter Property="BorderBrush" Value="{DynamicResource AccentColorBrush}"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="TabItem">
                    <StackPanel>
                        <Border x:Name="border" BorderBrush="{TemplateBinding BorderBrush}"
                                        Padding="12,2,24,2" 
                                        BorderThickness="0,0,0,4" 
                                        Margin="2,2,2,0"
                                        SnapsToDevicePixels="True">
                            <Border.Style>
                                <Style TargetType="Border">
                                    <Setter Property="Background">
                                        <Setter.Value>
                                            <SolidColorBrush Color="{DynamicResource Gray5}"/>
                                        </Setter.Value>
                                    </Setter>
                                </Style>
                            </Border.Style>
                            <Label x:Name="root" FontSize="15">
                                <Label.Style>
                                    <Style TargetType="Label">
                                        <Setter Property="Foreground">
                                            <Setter.Value>
                                                <SolidColorBrush Color="{DynamicResource BlackColor}" />
                                            </Setter.Value>
                                        </Setter>
                                    </Style>
                                </Label.Style>
                                <ContentPresenter ContentSource="Header" RecognizesAccessKey="True" />
                            </Label>
                        </Border>
                        <Canvas Height="10" Width="20" x:Name="arrow" Margin="25,0,0,0"
                                        HorizontalAlignment="Left" SnapsToDevicePixels="True">
                            <Path Data="M 0 0 H 20 L 10 10 Z"
                                          StrokeThickness="0"
                                          Fill="{DynamicResource AccentColorBrush}"/>
                        </Canvas>
                    </StackPanel>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsSelected" Value="true">
                            <Setter TargetName="root" Property="Foreground">
                                <Setter.Value>
                                    <SolidColorBrush Color="{DynamicResource WhiteColor}" />
                                </Setter.Value>
                            </Setter>
                            <Setter TargetName="border" Property="Background">
                                <Setter.Value>
                                    <SolidColorBrush Color="{DynamicResource AccentColor}"/>
                                </Setter.Value>
                            </Setter>
                            <Setter TargetName="border" Property="BorderBrush">
                                <Setter.Value>
                                    <SolidColorBrush Color="{DynamicResource AccentColor}"/>
                                </Setter.Value>
                            </Setter>
                            <Setter TargetName="arrow" Property="Visibility" Value="Visible"/>
                        </Trigger>
                        <Trigger Property="IsSelected" Value="false">
                            <Setter  TargetName="root" Property="Foreground">
                                <Setter.Value>
                                    <SolidColorBrush Color="{DynamicResource BlackColor}" />
                                </Setter.Value>
                            </Setter>
                            <Setter TargetName="arrow" Property="Visibility" Value="Hidden"/>
                        </Trigger>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter TargetName="root" Property="Foreground">
                                <Setter.Value>
                                    <SolidColorBrush Color="{DynamicResource WhiteColor}" />
                                </Setter.Value>
                            </Setter>
                            <Setter TargetName="border" Property="BorderBrush" Value="{DynamicResource AccentColorBrush}"></Setter>
                            <Setter TargetName="border" Property="Background">
                                <Setter.Value>
                                    <SolidColorBrush Color="{DynamicResource AccentColor}"/>
                                </Setter.Value>
                            </Setter>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

   </ResourceDictionary>
</UserControl.Resources>

The problem I have is that SolidColorBrush resources (AccentColorBrush, BlackColor, WhiteColor and Gray5) are not working when I am referring them through a DynamicResource. If I apply the colors directly within the style they are working.

Using DynamicResource cause an exception in design time and xaml view crashes, for example, for Gray5 resource is saying:

InvalidOperationException: '#FFD3D3D3' is not a valid value for property 'Color'.

Then I apply this style to my TabControl:

    <TabControl Grid.Row="1"
                Grid.RowSpan="5"
                Grid.Column="0"
                Grid.ColumnSpan="5">
        <TabControl.Resources>
            <Style TargetType="TabItem" BasedOn="{StaticResource AzureTabItem}"/>
        </TabControl.Resources>
        <TabItem Header="Home">
            <!-- cotent here -->
        </TabItem>
        <!-- some other TabItems here -->
    </TabControl>

Use the Brush resource(s) directly:

<Setter Property="Background" Value="{DynamicResource Gray5}">

...instead of creating another brush like this:

<Setter Property="Background">
    <Setter.Value>
        <SolidColorBrush Color="{DynamicResource Gray5}"/>
    </Setter.Value>
</Setter>

If you use the latter approach, you should define you resource as a Color:

<Color x:Key="Gray5">LightGray</Color>