Placing a widget at specific position overriding gridtemplate


My tabs generally follow a 10/10 layout, using % to size my widgets. I do it manually which becomes tedious after a while. I was wondering if there's an automatic way of doing it and discovered the gridtemplate property.
I understand that for this specific example, I would use something like this:

repeat(auto-fill, 10%) / repeat(auto-fill, 10%)

My question is: how can I override this template? I want to be able to put one button and the bottom (left: 90%, top:90%), even without having all the other rows and columns filled. How can I do this? How can I put a widget in a specific row, even though the previous isn't fully completed? I believe it has something to do with using !important in the CSS field, but haven't figure out the correct way to do it.

Well, I believe I found out my answer... at least one way of doing it. Dont know if its the most efficient, but this works.

:host {
grid-column: 10 / 10;
grid-row: 10 / 10;