How to Reduce the Height of a Slider

[j4587698]

I've been attempting to change the height of a Slider to 5 using the following XAML code:

<Style Selector="Slider:horizontal">
    <Setter Property="MinWidth" Value="40" />
    <Setter Property="MinHeight" Value="5" />
    <Setter Property="Template">
      <ControlTemplate>
        <Grid Name="grid">
          <Grid.Resources>

          </Grid.Resources>
          <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" MinHeight="5" />
            <RowDefinition Height="Auto" />
          </Grid.RowDefinitions>
          <suki:GlassCard Name="TrackBackground"
                  Grid.Row="1" Classes="Control"
                  Height="7"
                  Margin="0,0"
                  VerticalAlignment="Center"
                  BorderThickness="0"
                  CornerRadius="5" />

          <Track Name="PART_Track"
                 Grid.Row="1"
                 IsDirectionReversed="{TemplateBinding IsDirectionReversed}"
                 Orientation="Horizontal">
            <Track.DecreaseButton>
              <RepeatButton Name="PART_DecreaseButton"
                            Height="5"
                            Margin="0"
                            Padding="0"
                            HorizontalAlignment="Stretch"
                            Background="{DynamicResource SukiPrimaryColor}"
                            BorderThickness="0"
                            CornerRadius="5" />
            </Track.DecreaseButton>
            <Track.IncreaseButton>
              <RepeatButton Name="PART_IncreaseButton" Classes="repeattrack" />
            </Track.IncreaseButton>
            <Thumb Name="thumb" Margin="0">
              <Thumb.Template>
                <ControlTemplate>
                  <Grid Width="16" Height="16">
                    <Border Width="8"
                            Height="8"
                            Margin="0"
                            Background="White"
                            BorderThickness="0"
                            Classes="ThumbBorder ThumbB"
                            CornerRadius="{DynamicResource MediumCornerRadius}" />
                  </Grid>
                </ControlTemplate>
              </Thumb.Template>
            </Thumb>
          </Track>
        </Grid>
      </ControlTemplate>
    </Setter>
  </Style>

Everything seems to be working fine, but there is a strange offset that prevents my DecreaseButton from filling the entire Slider, and it doesn't connect properly with my Thumb.
Like this:

Can you tell me what might be causing this issue? Thank you very much for your assistance.