What is the best way to indent an element?

Question

css

After reading the book Ethan Marcotte - Responsive Web Design, it became clearer but not completely visible. On the screen is a normal 12 column grid at 1280 px. According to Ethan's book, it's quite normal to write a column width something like 17.23333333. Based on this, I can assume that: look at the screen. screenshot.ru/06d7d27b53897e183f19bc7de88dd4ef I want to understand how the width of the columns is set on the grid, from the element or from those columns on which the element itself even goes a little? The screenshot shows the width of the columns and the element. I understand that such a grid is just one of the options, there are many ways.

Answer 1

Or you didn’t fully express the idea or didn’t ask the question, maybe you don’t even fully understand what you don’t understand.
If you are so attached to the grid, then instead of a book, read the bootstrap source.
Why exactly %? There are px, em ... Or do you think that if it is written somewhere, then pixels cannot make the site adaptive? It is possible, at what and without a grid!!!
Reading your other questions, it became clear that you have a lot of theory (which you constantly doubt), but there is very little experience. Take a free psd layout, and without using css generators in brackets or whatever else, without using bootstrap and other ready-made grids. Just make up from scratch, google, look at the sources of other sites, learn how to make up step by step, do not copy-paste the code, do not hack. This, in my opinion, is the only way to finally understand why they do it in a specific way. Learn from your mistakes. In difficult situations, ask specific questions with references to the work you have done. With a specific description of the problem. For one thing, ask for criticism. After spending some time in practice, your doubts will disappear, but the theory will finally become useful.
Practice is your everything!
Hope it was helpful.
UPD: as for the question, it's really not clear what exactly you don't understand