@{
    var theme = new WebReportViewerTheme();

    theme.Colors.NavigationColor = "#495057";
    theme.Colors.NavigationBorderColor = "#495057";
    theme.Colors.NavigationColorSelected = "#343a40";
    theme.Colors.NavigationColorHover = "#6c757d";
    theme.Colors.SideBarColor = "#495057";
}
 
@Html.WebReportViewer("Vorschau", projectId, theme: theme);

<ll-webreportviewer
backendUrl="https://example.com/WebReportViewer"
defaultProject="57956062-8D88-4233-8187-673B27B12001"
theme="{'Colors':{
        'NavigationColor':'#495057',
        'NavigationBorderColor':'#495057',
        'NavigationColorSelected':'#343a40',
        NavigationColorHover':'#6c757d',
        'SideBarColor':'#495057'
        }}"
>
</ll-webreportviewer>