Hi there,
you could use some CSS like this:
.separate-containers .code-block + .site .site-main {
margin-top: 0;
}
If there is a div.code-block
, like you have for your banner ad, before the main site container then remove the spacing the theme applies to its top.
The rest of the space comes from the inline styles applied to that code block. ie.
<div class="code-block code-block-6" style="margin-top: 20px; margin-bottom: 5px; text-align: center; display: block; clear: both;">
If you can edit that HTML then you can adjust its margins too.