title: How to dynamically apply CSS in vue.js?
body: <p>This is my situation:</p>
  
  <p>I have a web app that allow users to change the UI size. (i.e. small, medium or large button)</p>
  
  <p>Users can change how it looks like dynamically during runtime. All text and form input boxes will be resized.</p>
  
  <p>My project is in Vue.js.</p>
  
  <p>What is the best way to solve this?  Loading different css when user click? </p>