inabox/InABox.Avalonia/Theme/Classes/Border.axaml

<Styles xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <Style Selector="Border.Standard">
        <Setter Property="BorderBrush" Value="{DynamicResource PrsTileBorder}" />
        <Setter Property="BorderThickness">
            <Setter.Value>
                <DynamicResource ResourceKey="PrsBorderThickness" />
            </Setter.Value>
        </Setter>
        <Setter Property="Background" Value="Transparent" />
        <Setter Property="CornerRadius" Value="{DynamicResource PrsCornerRadius}" />
        <Setter Property="Margin" Value="{DynamicResource PrsControlSpacing}" />
    </Style>

    <Style Selector="Border.Alert">
        <Setter Property="HorizontalAlignment" Value="Right" />
        <Setter Property="VerticalAlignment" Value="Top" />
        <Setter Property="Margin" Value="0,5,5,0" />
        <Setter Property="BorderBrush" Value="{DynamicResource PrsAlertBorder}" />
        <Setter Property="BorderThickness">
            <Setter.Value>
                <DynamicResource ResourceKey="PrsBorderThickness" />
            </Setter.Value>
        </Setter>
        <Setter Property="Background" Value="{DynamicResource PrsAlertBackground}" />
        <Setter Property="Height" Value="20" />
        <Setter Property="MinWidth" Value="20" />
        <Setter Property="CornerRadius" Value="10" />
    </Style>

</Styles>