Upload vector file in header

It’s because CSS is stretching the image:

.header {
...
     background-size: cover;
...
}

Hi Andrew, thanks!

I found the command but now I don’t know how to quit this stretching I’m just starting in programmation.

Search this article for the word “cover”: https://developer.mozilla.org/en-US/docs/Web/CSS/background-size

Thank you!!