Getting a vector to encompass text across adaptive views?

Hi guys Im trying to get some text and buttons on my hero page sitting consistently over a vector across adaptive views:

View Website

As you can see from the link, this placement works across the predefined breakpoints, but not when i scale the page between breakpoints. How to I ensure the vector consistently scales to encompass the text between views?

Thanks for your advice!


Here is my site Read-Only: LINK
(how to share your site Read-Only link)

This is the kind of layout im trying to make:

The vector in question is the white shape behind the text.
For mobile, the background image/video would not be visible and instead just the text.