Styling an Embed Text and Checkbox

Hi everybody,

I am trying to make an embedded text and checkbox look nicer. Here is what it looks like now (I’d like to make the text font Roboto, grey, and 20px - then make the checkbox bigger and flat/modern following Google Material Design

Current design:

Current embed code:

Collection Option 1

The reason for the embed is this:

If anybody knows HTML and CSS, I would really appreciate your help. Thanks!