Add a hover and pressed to the visual indication of MyButton.

gpt4all-chat/qml/MyButton.qml

@@ -14,11 +14,10 @@ Button {
         Accessible.name: text
     }
     background: Rectangle {
-        opacity: .5
-        border.color: theme.backgroundLightest
-        border.width: 1
+        border.color: myButton.down ? theme.backgroundLightest : theme.buttonBorder
+        border.width: 2
         radius: 10
-        color: theme.backgroundLight
+        color: myButton.hovered ? theme.backgroundLighter : theme.backgroundLight
     }
     Accessible.role: Accessible.Button
     Accessible.name: text

gpt4all-chat/qml/Theme.qml

@@ -12,6 +12,7 @@ QtObject {
     property color backgroundLight: "#343541"
     property color backgroundLighter: "#444654"
     property color backgroundLightest: "#7d7d8e"
+    property color buttonBorder: "#565869"
     property color dialogBorder: "#d1d5db"
     property color userColor: "#ec86bf"
     property color assistantColor: "#10a37f"