add style for the track
MODIFY
WalletWasabi.Fluent/Styles/Themes/Base.axaml
WalletWasabi.Fluent/Styles/Themes/Base.axaml
<SolidColorBrush x:Key="ActionButtonPointerOverBackgroundColor" Color="{DynamicResource SystemAccentColorLight1}" />
<SolidColorBrush x:Key="ActionButtonDisabledBackgroundColor" Color="{DynamicResource SystemControlDisabledBaseLowBrush}" />
+ <Color x:Key="SliderTrackFill">#8093AE</Color>
+ <Color x:Key="SliderTrackFillPointerOver">#8093AE</Color>
+ <Color x:Key="SliderTrackFillPressed">#8093AE</Color>
+
<SolidColorBrush x:Key="NavBarAccentColor">#97D234</SolidColorBrush>
<SolidColorBrush x:Key="NavBarAccentColorPressed">#719B2A</SolidColorBrush>
<SolidColorBrush x:Key="NavBarItemPressedAccentColor">#719B2A</SolidColorBrush>

add style for the track