What is the html page in this psd template for boostrap?

Question

css

Hello, maybe this is a stupid question, maybe there are experts who know how to google, but unfortunately I did not find the answer to my question, so I decided to turn here, and this is the question itself:
We are given a standard psd template on which there is markup , and I don't understand if the page starts from the 1 left synge column or from the beginning of the document?

Answer 1

For Bootstrap, this shouldn't bother you too much. there, by default, exactly the same, 12 columns and a content part aligned in the middle. The page starts at the top, the content part is in the center :)
"Blue columns" are the indents between the columns and some internal margins of the columns themselves, apparently.

Answer 2

you have two grids there,
but in general, in theory, from the second "blue column" because 15px padding between col

Answer 3

here is a link to the image
imgur.com/a/lDWSe