How can I proportion the size as the page width changes?

There is an feature with before in the navbar section on my page.
This feature takes shape as the page scale grows or shrinks.
But I always want to see it fixed.
How can I do that?

The version I always want to see
https://prnt.sc/25ltCANy_fGi
As it appears when reduced
https://prnt.sc/BjIz18TSVp4Z
How it looks when grown up
https://prnt.sc/LAu8i3u5dl-1

>Solution :

I would suggest you have 2 sections and the right hand section have the translater with the slanted background css color.