Dawn theme custom liquid video - different sizes on mobile and desktop

[Allunix]

Hello,

Recently, we uploaded a video to the homepage of our website.
A few days ago, we came across this brand's webpage. I wanted to change the custom liquid code, but none of the codes that I found worked.
So I would be grateful for a solution on how to make the video size on mobile like on the brand from the screenshot.
Here is the custom liquid code that I currently have:
<style>
video {
display: block;
margin: 0 auto;
width: 100%;
}

@media screen and (max-width: 800px) {
video {
width: 100%;
}
}
</style>

<video autoplay loop playsinline muted>
<source src="https://cdn.shopify.com/videos/c/o/v/d88ba5c896284d1a99679e4c96b5ef2c.mp4" />
</video>

[hammadCodes]

This will need to build a new section into the theme and make sure it is always behind the menu. Some coding is needed which an expert can perform. Your HTML code is correct but needs refinement