[Parameter]
public string Width { get; set; }

<DxButton Id="targetButton" Click="() => IsOpen = !IsOpen">Show a flyout window</DxButton>
<DxFlyout @bind-IsOpen=IsOpen PositionTarget="#targetButton" Width=400
    BodyText="Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor
            incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud
            exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat."
    HeaderVisible="true" HeaderText="Header" HeaderCssClass="header-footer-style"
    FooterVisible="true" FooterText="Footer" FooterCssClass="header-footer-style">
</DxFlyout>

@code {
    bool IsOpen { get; set; } = false;
}

.header-footer-style {
    font-style: italic;
}