Help please.

I would suggest using CSS for this, if you can. I'm not completely sure of what the issue is that you are facing, but if you want some white space, but not much, and you want your elements to grow with their contents, then you can use CSS.

Using CSS, when you set the min-height to be a certain height, this means that the element will not be less than that height, but will grow to whatever its contents require. So, if you had a small amount of content on one page, enough to where min-height: 400px would still leave enough white space below the contents, then the height would never go below 400px; however, if your content grows larger than 400px, the element will grow, since its MINIMUM height value is still in tact, with its height growing to greater than 400px (whatever the contents grow to, the element will grow to accommodate them, as well).

Anytime you set a specific height, such as height: 90% or height: 700px, this sets the exact height that the element will be. However, if you give it criteria to follow that is flexible, such as a minimum or maximum height, or even leaving out the height altogether (which will make the element stick with whatever the contents take up, only being as big as the contents), then the element will maintain any height that is within those criteria. So for min-height: 400px, it will never get less than 400px, but it can get infinitely greater because that will mean that it still fits the minimum height criteria set. The same with the max-height: if max-height: 400px, then the element will be anywhere from 0px in height to 400px in height, depending what the contents make it grow to be, since this will fit within the criteria of not be more than the maximum height of 400px.