Black lines on code block video

Hello:)

I have these black lines on the side of my video. I used this tutorial to add in my video: https://www.katescott.co/blog/squarespace-animations. 

In code block:

<video autoplay="autoplay" muted loop="true" width="100%" controls>

  <source src="https://static1.squarespace.com/static/61d0f1f92ffb8339ed5a974b/t/639fdda26868072f56a019d3/1671421354482/branding-z_social-implementation-800x450.mp4" type="video/mp4">

</video>

CSS:
.video {
  background-color: white;
  pointer-events: none;
  position: center;
  aspect-ratio:  16/9;
}

How can I get rid of those black lines?

BTW, the video itself doesn't have those lines. 

Site: https://www.makellwebb.com/branding

It's fine on my browser! I take it you fixed it?

Fixed it on some areas. But now I'm not able to fix it on others 🙃

https://www.makellwebb.com/industrial-design

This video was added as a video. (Manage Custom Files won't let me upload videos anymore. Regardless of file size.)

Current CSS:

The border trick for the previous video didn't work here.