I have a sidebar on the left which is fixed (width: 400px) and content on the right which should contain the rest of the space. While using `fill-available`: the sidebar changes its width to 309px.

Why doesn't `fill-available` work properly? Is there a possibility to set content in the remained space?

Please find the codepen here: <https://codepen.io/ullaakut/pen/eQxbvY>

Thanks!