Just Follow the follwoing steps and let me know if you have any problem with this. Out of these you meight be aware already. May be you miss something.
1) Add ResourceDictionary as style sheet.
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:XYZApplication">
<!-- Style 1-->
<Style x:Key="GridStyle1" TargetType="{x:Type Grid}">
<Setter Property="Background" Value="BlanchedAlmond"></Setter>
<Setter Property="Margin" Value="1,1,1,1"></Setter>
</Style>
<!-- Style 2-->
<Style x:Key="GridStyle2" TargetType="{x:Type Grid}">
<Setter Property="Background" Value="Aqua"></Setter>
<Setter Property="Margin" Value="5,5,5,5"></Setter>
</Style>
</ResourceDictionary>
2) Add resource file into your user control/window as follows...
<UserControl x:Class="XYZApplication.Views.Payment"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:XYZApplication.Views"
mc:Ignorable="d">
<UserControl.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="../Style/Styles.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</UserControl.Resources>
</UserControl>
3) Use those specific styles to designated grid inside the usercontrol/window
<Grid Style="{StaticResource GridStyle1}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="Auto"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<Grid Grid.Column="1" Grid.Row="1" Style="{StaticResource GridStyle2}" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="Auto"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<Label Grid.Column="0" Grid.Row="0">Bank Name</Label>
<Label Grid.Column="1" Grid.Row="0">Branch</Label>
<Label Grid.Column="2" Grid.Row="0">Account holder</Label>
<Label Grid.Column="3" Grid.Row="0">Account Number</Label>
<Label Grid.Column="4" Grid.Row="0">Balance</Label>
<Label Grid.Column="0" Grid.Row="1">Bank of ...</Label>
<Label Grid.Column="1" Grid.Row="1">...Branch</Label>
<Label Grid.Column="2" Grid.Row="1">My Name</Label>
<Label Grid.Column="3" Grid.Row="1">Account Number 123</Label>
<Label Grid.Column="4" Grid.Row="1">1 billion</Label>
</Grid>
</Grid>
You can add these both styles in code behind also.
Hope it helps!!!