refactor: enhance UI components and improve theme properties for better visual consistency

src/pygui/ISC/Tabs/SettingsTab.qml

@@ -107,25 +107,29 @@ Item {
             x: toggle.leftPadding
             y: parent.height / 2 - height / 2
             radius: Theme.radiusXs
-            color: toggle.checked ? Theme.primaryAccent : Theme.fieldBackground
+            color: toggle.checked ? Theme.primaryAccent : "transparent"
             border.width: Theme.borderThin
             border.color: toggle.checked ? Theme.primaryAccent : Theme.fieldBorder
 
-            Rectangle {
+            Text {
                 anchors.centerIn: parent
-                width: 9
-                height: 9
-                radius: Theme.radiusXs
+                text: "✓"
+                font.pixelSize: 14
+                font.bold: true
+                color: Theme.panelBackground
                 visible: toggle.checked
-                color: Theme.fieldBackground
+                // Small nudge to center the checkmark perfectly
+                verticalAlignment: Text.AlignVCenter
+                horizontalAlignment: Text.AlignHCenter
             }
         }
 
         contentItem: Text {
             text: toggle.text
-            color: Theme.checkboxText
+            color: Theme.headingColor
             verticalAlignment: Text.AlignVCenter
             leftPadding: toggle.indicator.width + toggle.spacing
+            font.pixelSize: 13
         }
     }