Custom Theme Problem

I’m building (or trying to) a completely custom theme from scratch.
Its taking me a while to do but I think a better understanding of the themes will pay off in the long run.

Anyway, I’m having a problem that I just can’t get the answer to.

The main content has a content box with 3 div’s in it.
The top and bottom div is just for an effect on the site while the middle div contains the page and post content.

The problem is, I can’t close the gap between the 3 div’s to give me the effect I want.

Here is the site:
https://thevickerys.eu/

as you can see on the home page and the sample page the gap is closed between the first and second div bit I can’t close the lower div up to the second div.

On the next sample page I can’t close the gap between all 3 div’s.

Here is the css that related to the 3 divs.
[CSS moderated as per the Forum Rules. Please just post a link to your site.]

On the index.php here is the code that runs the above css

<div id="mainarea">
<div class="contentwrap">
  <div class="contentbordertop"></div>
  <div class="content">
  <?php
			/* Run the loop to output the posts. */
			 get_template_part( 'loop', 'index' );
		?>
  </div>
  <div class="contentborderbottom"></div>
</div>

I have been at this for days and I can’t move on until I fix this….. its driving me nuts and I’m starting to loose hope in it.

Can anyone help???????