Our web application has a small header and nav menu at the very top, and below, there is simply a large area of open space. We have no need for an always-present sidebar, so there is just one column. The layout is 100% window width, so it allows those with wide screens to use as much space as possible.
Our issue is that there are often times where certain one-page forms are very small and don't need to take much space. And the form can sometimes look awkward in the potentially huge open space below the header.
For instance, the password reset form below only requires two inputs. It is awkward to make the form 100% of the page width, so we kept it fairly narrow. But then, there is a ton of white space that isn't filled.
I feel that a narrow form should be centered, so there is equal white space on each side, and so you don't have to move your head away from the center of the screen.
But a co-worker feels that a narrow form should be left-aligned, because most everything else (like blocks of text) is left-aligned.
What do you guys think? Are there any principles or guidelines to follow for how to align entire forms? I've found tons of info on how to align labels, buttons, etc., but not on how to align forms when they don't take up the whole page.
The form - centered,
The form - left-aligned,