CSS box "flow"/stacking (see screenshot) -

The boxes shown in the attached screenshot are taking me hard times as the flow. Seeing me, I'm not even sure what this technique is called, it's making it difficult.

Update: Thank you Jonathan, it's close, but it's clear that I do not have it

Well described this problem, each box has a category title, and the unknown record (bookmark) related to that title - maybe two, maybe Is 50

Let's say I have six bookmark categories because users can enter multiple or some bookmarks, because they are in every category (whichever is unlimited), I really do not know How big would any box be?

In the new enclosed depiction, it's better, I hope.

I prefer not to be in a certain number of columns, because the width of the container depends on the user's screen resolution. Therefore, the less resolution may be room for two columns, while the higher resolution There is room for five columns / large browser width.

I can use it somehow, but this is not correct, and if it is a stereotypical CSS method to do so, then 'D is very much liked.

Using the Jonathan Code has been suggested, it will work well if each category is about the same bookmarks and I was okay with using a fixed column layout, but When there are 50 bookmarks in one category, while the other has only three, many places are wasted.

No. If you can not rely on the number of columns then there is no CSS-only solution (though it seems that in CSS3 - a fun idea). You will need JS.