How do I format embedded video so it's centered when viewing on mobile?

Site URL: https://www.totemgenekeys.com/totems/kiwi

I'm not a coder, so I'm totally lost with this. I am grabbing media from Reddit and using their 'embed' feature. I copy and pasting the provided iframe code into a Code Block. (When I attempt this with an Embed Block it only returns 'null')

The media does show up but the trouble is, it displays with a width and height formatted for desktop, and is left aligned. I.e. half the video is cut off when viewing on a smaller screen). 

I want it to resize when viewing on mobile, and have it be centered on mobile devices.

Sample of the HTML:

<iframe id="reddit-embed" src="https://www.redditmedia.com/r/MadeMeSmile/comments/o12bua/this_kiwi_falling_over_from_excitement_of_finding/?ref_source=embed&amp;ref=share&amp;embed=true" sandbox="allow-scripts allow-same-origin allow-popups" style="width:100%" height="517" width="640" scrolling="no"></iframe>
 

On 8/5/2021 at 12:06 AM, homeostace said:

Site URL: https://www.totemgenekeys.com/totems/kiwi

I'm not a coder, so I'm totally lost with this. I am grabbing media from Reddit and using their 'embed' feature. I copy and pasting the provided iframe code into a Code Block. (When I attempt this with an Embed Block it only returns 'null')

The media does show up but the trouble is, it displays with a width and height formatted for desktop, and is left aligned. I.e. half the video is cut off when viewing on a smaller screen). 

I want it to resize when viewing on mobile, and have it be centered on mobile devices.

 

Sample of the HTML:

<iframe id="reddit-embed" src="https://www.redditmedia.com/r/MadeMeSmile/comments/o12bua/this_kiwi_falling_over_from_excitement_of_finding/?ref_source=embed&amp;ref=share&amp;embed=true" sandbox="allow-scripts allow-same-origin allow-popups" style="width:100%" height="517" width="640" scrolling="no"></iframe>
 

Seems like the video dimension is set inside the iframe, since it is external iframe, we can not edit how element inside it display

Thanks @bangank36. I deleted the width and height inside the embed code, and now the video fits better on mobile. It's a small video on desktop, but it's OK since most of my users view my pages via mobile. 

For reference, here was my original embed code:

<iframe width="560" height="315" src="https://www.youtube.com/embed/dQw4w9WgXcQ" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

and here is the updated embed code now:

<iframe src="https://www.youtube.com/embed/dQw4w9WgXcQ" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>