Make font size themeable.

main.qml

@@ -55,7 +55,7 @@ Window {
                 anchors.top: modelLabel.top
                 anchors.bottom: modelLabel.bottom
                 anchors.horizontalCenter: parent.horizontalCenter
-                font.pixelSize: 24
+                font.pixelSize: theme.fontSizeLarge
                 spacing: 0
                 model: LLM.modelList
                 Accessible.role: Accessible.ComboBox
@@ -77,7 +77,7 @@ Window {
                     contentItem: Text {
                         text: modelData
                         color: theme.textColor
-                        font: control.font
+                        font: comboBox.font
                         elide: Text.ElideRight
                         verticalAlignment: Text.AlignVCenter
                     }
@@ -612,7 +612,7 @@ Window {
                         wrapMode: Text.WordWrap
                         focus: false
                         readOnly: true
-                        font.pixelSize: 24
+                        font.pixelSize: theme.fontSizeLarge
                         cursorVisible: currentResponse ? (LLM.response !== "" ? LLM.responseInProgress : false) : false
                         cursorPosition: text.length
                         background: Rectangle {
@@ -841,7 +841,7 @@ Window {
                 color: theme.textColor
                 padding: 20
                 enabled: LLM.isModelLoaded
-                font.pixelSize: 24
+                font.pixelSize: theme.fontSizeLarge
                 placeholderText: qsTr("Send a message...")
                 placeholderTextColor: theme.backgroundLightest
                 background: Rectangle {

qml/NetworkDialog.qml

@@ -87,7 +87,7 @@ NOTE: By turning on this feature, you will be sending your data to the GPT4All O
             padding: 20
             width: parent.width
             text: settings.attribution
-            font.pixelSize: 24
+            font.pixelSize: theme.fontSizeLarge
             placeholderText: qsTr("Please provide a name for attribution (optional)")
             placeholderTextColor: theme.backgroundLightest
             background: Rectangle {

qml/Theme.qml

@@ -12,4 +12,5 @@ QtObject {
     property color dialogBorder: "#d1d5db"
     property color userColor: "#ec86bf"
     property color assistantColor: "#10a37f"
+    property real  fontSizeLarge: 24
 }

qml/ThumbsDownDialog.qml

@@ -55,7 +55,7 @@ Dialog {
                 width: parent.width
                 height: 300
                 wrapMode: Text.Wrap
-                font.pixelSize: 24
+                font.pixelSize: theme.fontSizeLarge
                 placeholderText: qsTr("Please provide a better response...")
                 placeholderTextColor: theme.backgroundLightest
                 background: Rectangle {