Background color is easier to change in App.xaml as override:
<Application.Resources>
<ResourceDictionary>
<SolidColorBrush x:Key="ListViewItemSelectedPointerOverBackgroundThemeBrush" Color="#56c2ff" />
<SolidColorBrush x:Key="ListViewItemSelectedPointerOverBorderThemeBrush" Color="#56c2ff" />
<SolidColorBrush x:Key="ListViewItemSelectedBackgroundThemeBrush" Color="#56c2ff" />
...