CheckBoxStyleTemplate

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2006"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" >

    <Style x:Key="CheckBoxStyle" TargetType="{x:Type CheckBox}">
        <Setter Property="Foreground" Value="#15a1e2"/>
        <Setter Property="VerticalAlignment" Value="Center" />
        <Setter Property="Background" Value="#15a1e2"/>
        <Setter Property="BorderBrush" Value="#15a1e2"/>
        <Setter Property="Content" Value="{StaticResource Content}" />
        <Setter Property="Template">
            <Setter.Value>

                <ControlTemplate TargetType="{x:Type CheckBox}">
                    <StackPanel Orientation="Horizontal">
                        <ContentPresenter Margin="0,0,5,0"/>
                        <Border x:Name="Border"
                                  Width="15"
                                  Height="15"
                                  CornerRadius="0"
                                  Background="Transparent"
                                  BorderThickness="3"
                                  BorderBrush="#15a1e2">
                            <Path x:Name="CheckMark"
                                  Data="M0.45370397,2.9789081 L4.8584409,5.1201844 L9.0095177,0.42685521 L9.0092859,5.1932764 L5.0808349,8.7450323 L0.49096614,6.3567581 z"
                                  Fill="#15a1e2"
                                  Stretch="Fill"
                                  StrokeThickness="2"
                                  UseLayoutRounding="False"
                                  Visibility="Collapsed"
                                  Margin="0.302,0.089,0.141,0.593"  />
                        </Border>
                    </StackPanel>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsChecked" Value="true">
                            <Setter TargetName="CheckMark" Property="Visibility" Value="Visible" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>