Can't get rid of w-nav background

Hi All,

I published al-kemia.com a while ago and I’m making regular updates.
Since today, 2020/12/08, the Nav Bar has a .w-nav class with a background #ddd that only shows once published.

I did not set any class “w-nav”, and the w-nav{background: #ddd;} doest not shows in the Designer. It will only shows on the live site: www.al-kemia.com .

I tried adding a custom CSS script in the header :

OR

<script>
	.w-nav {
    background: none !important;
    }
</script> 

It does not work.

Thanks in advance for your help!
-Valentin

Here is my site Read-Only: https://preview.webflow.com/preview/alkemia?utm_medium=preview_link&utm_source=dashboard&utm_content=alkemia&preview=2b87c84bd1c52a6a24cf3a7cd09986da&mode=preview