No, The website custom theme or any 3rd party theme will not affect the mobile app theme. The Mobile app is the native app. The App has its own theme.
In the mobile app, the color combination, app name, app logo, images, font etc. will be changed as per the customers' business requirement.
Now you can easily make your iOS mobile application attractive by customizing the color scheme for your iOS application, from here, https://mobikul.com/mobikul-ios-gradient/
The gradient of the color for iOS a…