How can I adjust the width of a certain button I added in?

[michaelecom]

The website is:

https://wealth-strategies.myshopify.com/

I have added the following code to the "Custom HTML" section on the Prestige theme:

<a href="https://bit.ly/39xhdep" class="Button Button--primary Button--Full Button">View Course</a><br> 

I need to make the button the entire length of the video.

I tried the "Full" option and it did not work, I read about adding CSS code but I have no idea how to do that with this current button - I had to make the code like that for it to display as a block.

Any help is very appreciated!