LanMountainDesktop/LanMountainDesktop/Views/SettingsPages/RegionSettingsPage.axaml

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:ui="using:FluentAvalonia.UI.Controls"
             xmlns:fi="using:FluentIcons.Avalonia.Fluent"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="600"
             x:Class="LanMountainDesktop.Views.SettingsPages.RegionSettingsPage">

    <StackPanel x:Name="RegionSettingsPanel"
                Spacing="16">
        <TextBlock x:Name="RegionPanelTitleTextBlock"
                   FontSize="24"
                   FontWeight="SemiBold"
                   Foreground="{DynamicResource TextFillColorPrimaryBrush}"
                   Text="Region" />

        <Border Classes="settings-expander-shell">
            <ui:SettingsExpander x:Name="LanguageSettingsExpander"
                                 Header="Language"
                                 Description="Select application language. Changes apply immediately.">
                <ui:SettingsExpander.IconSource>
                    <fi:SymbolIconSource Symbol="Translate" />
                </ui:SettingsExpander.IconSource>
                <ui:SettingsExpander.Footer>
                    <ComboBox x:Name="LanguageComboBox"
                              Width="220">
                        <ComboBoxItem x:Name="LanguageChineseItem" Tag="zh-CN" Content="涓枃" />
                        <ComboBoxItem x:Name="LanguageEnglishItem" Tag="en-US" Content="English" />
                    </ComboBox>
                </ui:SettingsExpander.Footer>
            </ui:SettingsExpander>
        </Border>

        <Border Classes="settings-expander-shell">
            <ui:SettingsExpander x:Name="TimeZoneSettingsExpander"
                                 Header="Time Zone"
                                 Description="Select a time zone. Clock and calendar widgets will follow this zone.">
                <ui:SettingsExpander.IconSource>
                    <fi:SymbolIconSource Symbol="Clock" />
                </ui:SettingsExpander.IconSource>
                <ui:SettingsExpander.Footer>
                    <ComboBox x:Name="TimeZoneComboBox"
                              Width="280" />
                </ui:SettingsExpander.Footer>
            </ui:SettingsExpander>
        </Border>
    </StackPanel>
</UserControl>