Ionic2 ,how to use same theme for website and mobile application

I am building a website using html , css & angular 2 and a mobile application using ionic 2 framework . I have purchased a theme for the website, and the theme’s code is in angular 2 and is working fine for the website. Since Ionic 2 uses angular 2, so how to integrate same theme in Ionic 2 application. Also I wanted to know , how to use existing angular 2 project in Ionic 2.