Ionic Toolbar Fade as User Scrolls

We use ion-tab-bar and ion-tab-button to control the tabs in the bottom of our Ionic app. I have wrapped each button in a div, and can control the border-radius, background-color, etc. fairly easily with CSS, HOWEVER what I would like to do is make it so when a user starts to scroll down, that the background color of the buttons and text on the buttons fade to transparent - displaying only the icons. Does anyone know how to do that with Ionic tags? Or is this something only Javascript can do? Thank you for your response and noodling on this! Jonathon

This can be achieved using CSS transitions. No need for javascript. Using CSS transitions - CSS: Cascading Style Sheets | MDN