App.xaml

<Application x:Class="TaskCost.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Application.Resources>
    <SolidColorBrush x:Key="AccentBrush" Color="#0F6CBD"/>
    <SolidColorBrush x:Key="PanelBrush" Color="#FFFFFF"/>
    <SolidColorBrush x:Key="LineBrush" Color="#E6E6E6"/>
    <Style TargetType="Button">
      <Setter Property="FontFamily" Value="Segoe UI"/>
      <Setter Property="Background" Value="#F8F8F8"/>
      <Setter Property="BorderBrush" Value="#D5D5D5"/>
      <Setter Property="Padding" Value="14,7"/>
      <Setter Property="Cursor" Value="Hand"/>
      <Setter Property="Template">
        <Setter.Value>
          <ControlTemplate TargetType="Button">
            <Border x:Name="box" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="1" CornerRadius="5" Padding="{TemplateBinding Padding}">
              <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
            </Border>
            <ControlTemplate.Triggers>
              <Trigger Property="IsMouseOver" Value="True"><Setter TargetName="box" Property="Background" Value="#ECECEC"/></Trigger>
            </ControlTemplate.Triggers>
          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>
    <Style TargetType="DataGridColumnHeader">
      <Setter Property="Background" Value="White"/><Setter Property="BorderBrush" Value="#E8E8E8"/><Setter Property="BorderThickness" Value="0,0,1,1"/>
      <Setter Property="Padding" Value="10,7"/><Setter Property="FontWeight" Value="Normal"/><Setter Property="HorizontalContentAlignment" Value="Left"/>
    </Style>
    <Style TargetType="DataGridCell">
      <Setter Property="BorderThickness" Value="0"/><Setter Property="Padding" Value="9,5"/><Setter Property="VerticalContentAlignment" Value="Center"/>
      <Style.Triggers><Trigger Property="IsSelected" Value="True"><Setter Property="Background" Value="#D9EDFA"/><Setter Property="Foreground" Value="#111"/></Trigger></Style.Triggers>
    </Style>
  </Application.Resources>
</Application>