diff --git a/Styles/Theme.xaml b/Styles/Theme.xaml
index 989a56e..1248e68 100644
--- a/Styles/Theme.xaml
+++ b/Styles/Theme.xaml
@@ -31,6 +31,12 @@
     <FontFamily x:Key="ModernFont">Segoe UI, Apple SD Gothic Neo, Malgun Gothic</FontFamily>
     <FontFamily x:Key="IconFont">Segoe MDL2 Assets, Segoe Fluent Icons</FontFamily>
 
+    <!-- Global System Brushes Override (WPF DataGrid 기본 선택색 덮어쓰기) -->
+    <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="#2563EB" />
+    <SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}" Color="#FFFFFF" />
+    <SolidColorBrush x:Key="{x:Static SystemColors.InactiveSelectionHighlightBrushKey}" Color="#1E3A8A" />
+    <SolidColorBrush x:Key="{x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}" Color="#FFFFFF" />
+
     <!-- Nav Button Style -->
     <Style x:Key="NavButtonStyle" TargetType="RadioButton">
         <Setter Property="Background" Value="Transparent" />
@@ -152,7 +158,7 @@
     <!-- Modern TextBox Style -->
     <Style x:Key="ModernTextBoxStyle" TargetType="TextBox">
         <Setter Property="Background" Value="#0F172A" />
-        <Setter Property="Foreground" Value="{StaticResource TextPrimaryBrush}" />
+        <Setter Property="Foreground" Value="#FFFFFF" />
         <Setter Property="BorderBrush" Value="{StaticResource CardBorderBrush}" />
         <Setter Property="BorderThickness" Value="1" />
         <Setter Property="Padding" Value="10,6" />
@@ -194,13 +200,117 @@
         <Setter Property="Margin" Value="6" />
     </Style>
 
-    <!-- Modern DataGrid Style -->
+    <!-- ============================================================================== -->
+    <!-- Modern ComboBox & ComboBoxItem Style (선택칸 고대비 가독성 강화) -->
+    <!-- ============================================================================== -->
+
+    <Style TargetType="ComboBoxItem">
+        <Setter Property="Background" Value="#1E293B" />
+        <Setter Property="Foreground" Value="#F8FAFC" />
+        <Setter Property="Padding" Value="10,8" />
+        <Setter Property="FontSize" Value="13" />
+        <Setter Property="FontFamily" Value="{StaticResource ModernFont}" />
+        <Setter Property="Cursor" Value="Hand" />
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="ComboBoxItem">
+                    <Border x:Name="itemBorder"
+                            Background="{TemplateBinding Background}"
+                            Padding="{TemplateBinding Padding}">
+                        <ContentPresenter HorizontalAlignment="Left" VerticalAlignment="Center" />
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                            <Setter TargetName="itemBorder" Property="Background" Value="#2563EB" />
+                            <Setter Property="Foreground" Value="#FFFFFF" />
+                        </Trigger>
+                        <Trigger Property="IsSelected" Value="True">
+                            <Setter TargetName="itemBorder" Property="Background" Value="#1D4ED8" />
+                            <Setter Property="Foreground" Value="#FFFFFF" />
+                            <Setter Property="FontWeight" Value="SemiBold" />
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style TargetType="ComboBox">
+        <Setter Property="Background" Value="#0F172A" />
+        <Setter Property="Foreground" Value="#F8FAFC" />
+        <Setter Property="BorderBrush" Value="{StaticResource CardBorderBrush}" />
+        <Setter Property="BorderThickness" Value="1" />
+        <Setter Property="Padding" Value="8,4" />
+        <Setter Property="FontFamily" Value="{StaticResource ModernFont}" />
+        <Setter Property="FontSize" Value="13" />
+    </Style>
+
+    <!-- ============================================================================== -->
+    <!-- Modern DataGrid, ColumnHeader, Row, Cell Styles (그리드 선택칸 고대비 가독성 보장) -->
+    <!-- ============================================================================== -->
+
+    <!-- 1. DataGrid Column Header (어두운 배경 + 밝고 선명한 텍스트) -->
+    <Style TargetType="DataGridColumnHeader">
+        <Setter Property="Background" Value="#090D16" />
+        <Setter Property="Foreground" Value="#E2E8F0" />
+        <Setter Property="FontWeight" Value="Bold" />
+        <Setter Property="FontSize" Value="12" />
+        <Setter Property="Padding" Value="12,10" />
+        <Setter Property="BorderBrush" Value="#334155" />
+        <Setter Property="BorderThickness" Value="0,0,1,1" />
+        <Setter Property="HorizontalContentAlignment" Value="Left" />
+    </Style>
+
+    <!-- 2. DataGrid Cell (선택 시 텍스트 명확화) -->
+    <Style TargetType="DataGridCell">
+        <Setter Property="Padding" Value="10,8" />
+        <Setter Property="BorderThickness" Value="0" />
+        <Setter Property="FocusVisualStyle" Value="{x:Null}" />
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="DataGridCell">
+                    <Border Background="{TemplateBinding Background}" Padding="{TemplateBinding Padding}">
+                        <ContentPresenter VerticalAlignment="Center" />
+                    </Border>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+        <Style.Triggers>
+            <Trigger Property="IsSelected" Value="True">
+                <Setter Property="Background" Value="#2563EB" />
+                <Setter Property="Foreground" Value="#FFFFFF" />
+                <Setter Property="FontWeight" Value="SemiBold" />
+            </Trigger>
+        </Style.Triggers>
+    </Style>
+
+    <!-- 3. DataGrid Row (호버 및 선택 시 진한 파란색 배경 + 순백색 글자 강제) -->
+    <Style TargetType="DataGridRow">
+        <Setter Property="Background" Value="Transparent" />
+        <Setter Property="Foreground" Value="#F8FAFC" />
+        <Setter Property="FontFamily" Value="{StaticResource ModernFont}" />
+        <Setter Property="FontSize" Value="12.5" />
+        <Setter Property="Cursor" Value="Hand" />
+        <Style.Triggers>
+            <Trigger Property="IsMouseOver" Value="True">
+                <Setter Property="Background" Value="#1E3A8A" />
+                <Setter Property="Foreground" Value="#FFFFFF" />
+            </Trigger>
+            <Trigger Property="IsSelected" Value="True">
+                <Setter Property="Background" Value="#2563EB" />
+                <Setter Property="Foreground" Value="#FFFFFF" />
+                <Setter Property="FontWeight" Value="SemiBold" />
+            </Trigger>
+        </Style.Triggers>
+    </Style>
+
+    <!-- 4. Global Modern DataGrid Style -->
     <Style x:Key="ModernDataGridStyle" TargetType="DataGrid">
         <Setter Property="Background" Value="{StaticResource CardBgBrush}" />
         <Setter Property="BorderBrush" Value="{StaticResource CardBorderBrush}" />
         <Setter Property="BorderThickness" Value="1" />
-        <Setter Property="Foreground" Value="{StaticResource TextPrimaryBrush}" />
-        <Setter Property="RowBackground" Value="Transparent" />
+        <Setter Property="Foreground" Value="#F8FAFC" />
+        <Setter Property="RowBackground" Value="#1E293B" />
         <Setter Property="AlternatingRowBackground" Value="#162032" />
         <Setter Property="GridLinesVisibility" Value="Horizontal" />
         <Setter Property="HorizontalGridLinesBrush" Value="#2D3748" />
@@ -214,4 +324,12 @@
         <Setter Property="FontSize" Value="12.5" />
     </Style>
 
+    <!-- CheckBox Style for DataGrid Selection -->
+    <Style TargetType="CheckBox">
+        <Setter Property="Foreground" Value="#F8FAFC" />
+        <Setter Property="FontSize" Value="13" />
+        <Setter Property="Cursor" Value="Hand" />
+        <Setter Property="VerticalAlignment" Value="Center" />
+    </Style>
+
 </ResourceDictionary>
diff --git a/config.json b/config.json
index 42093fc..b35d64f 100644
--- a/config.json
+++ b/config.json
@@ -1,35 +1,35 @@
-{
-  "Application": {
-    "LiveMode": false,
-    "Theme": "Dark",
-    "AutoRefreshSeconds": 60
-  },
-  "ActiveDirectory": {
-    "UseLive": false,
-    "DomainController": "dc01.corp.local",
-    "Domain": "corp.local",
-    "BaseOU": "DC=corp,DC=local",
-    "UseLdaps": false,
-    "Username": "",
-    "Password": ""
-  },
-  "NetApp": {
-    "UseLive": false,
-    "ClusterEndpoint": "https://10.200.10.50",
-    "Port": 443,
-    "DefaultSvm": "svm_cifs_prod01",
-    "Username": "admin",
-    "Password": "",
-    "IgnoreSslErrors": true
-  },
-  "MsSql": {
-    "UseLive": false,
-    "Server": "localhost",
-    "AuthType": "Integrated",
-    "Username": "sa",
-    "Password": "",
-    "DefaultDatabase": "master",
-    "ConnectionTimeout": 10,
-    "BackupDirectory": "C:\\Backups"
-  }
-}
+{
+    "ActiveDirectory":  {
+                            "UseLive":  true,
+                            "DomainController":  "dc01.corp.local",
+                            "Domain":  "corp.local",
+                            "UseLdaps":  false,
+                            "BaseOU":  "DC=corp,DC=local",
+                            "Username":  "",
+                            "Password":  ""
+                        },
+    "NetApp":  {
+                   "UseLive":  true,
+                   "Password":  "",
+                   "IgnoreSslErrors":  true,
+                   "ClusterEndpoint":  "https://10.200.10.50",
+                   "DefaultSvm":  "svm_cifs_prod01",
+                   "Port":  443,
+                   "Username":  "admin"
+               },
+    "MsSql":  {
+                  "AuthType":  "Integrated",
+                  "Username":  "sa",
+                  "BackupDirectory":  "C:\\Backups",
+                  "DefaultDatabase":  "master",
+                  "Password":  "",
+                  "ConnectionTimeout":  10,
+                  "UseLive":  true,
+                  "Server":  "localhost"
+              },
+    "Application":  {
+                        "LiveMode":  true,
+                        "AutoRefreshSeconds":  60,
+                        "Theme":  "Dark"
+                    }
+}
\ No newline at end of file