Input font size?

Searched for that and no luck.
I’m moving a learning project (yes, new person) from codepen to atom. I have an input box and I want the user’s input to be big. In and on my website, telling CSS to make the font in that div big works. Doesn’t happen in atom; the input stays tiny.

Is there anythign I could/should do about that?

Is this a css/html coding or Atom editor question?
It is hard to tell with so very little specific detail.
Coding questions get better answers elsewhere.