Layout

A grid is a way to keep related things aligned. It is a tool. It is not a style, and a page can be well made without a visible modular system.

Columns, margins, and a baseline (if you use one) should be decided from the thing you are laying out: the line length a reader can hold, the size of photographs, the number of languages, the trim of the sheet. Copying a 12-column diagram from a textbook without measuring the page you have is a decoration, not a method.

Once a grid is set, the interesting work is often where something steps off it on purpose: a figure that bleeds, a heading that spans, a caption that hangs. If everything is aligned and the page is still hard to read, the type size or the line length is usually the problem, not a missing column.

On a screen, a grid has to survive a range of widths. A fixed number of columns that only works at one desktop size is a poster, not a layout for a site. Measure the shortest line you will actually publish, and the longest, before you decide how many columns you need.