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

<DxChart Data="@DataSource" Width="100%">
    @* ... *@
    <DxChartValueAxis>
        <DxChartAxisStrip StartValue="@HighAverage"
                          Color="rgba(255, 155, 85, 0.15)">
            <DxChartAxisStripLabel Text="Above average high">
                <DxChartFont Color="@HighAverageColor" Weight="500" Size="14"/>
            </DxChartAxisStripLabel>
        </DxChartAxisStrip>
        <DxChartAxisStrip EndValue="LowAverage"
                          Color="rgba(97, 153, 230, 0.1)">
            <DxChartAxisStripLabel Text="Below average low">
                <DxChartFont Color="@LowAverageColor" Weight="500" Size="14" />
            </DxChartAxisStripLabel>
        </DxChartAxisStrip>
    </DxChartValueAxis>
</DxChart>

@code {
    // ...
    double HighAverage = 60.8;
    double LowAverage = 53;
    string HighAverageColor = "#ff9b52";
    string LowAverageColor = "#6199e6";
}