fix(toolbox): Constrain toolbox width on large mobile device

react/features/toolbox/components/native/styles.js

@@ -65,6 +65,7 @@ const styles = {
     toolbar: {
         alignItems: 'center',
         backgroundColor: ColorPalette.darkBackground,
+        borderRadius: 3,
         flexDirection: 'row',
         flexGrow: 0,
         justifyContent: 'space-between',
@@ -77,7 +78,11 @@ const styles = {
      */
     toolbox: {
         flexDirection: 'column',
-        flexGrow: 0
+        flexGrow: 0,
+        width: '100%',
+        maxWidth: 500,
+        marginLeft: 'auto',
+        marginRight: 'auto'
     }
 };