First of all you need to understand the differences between dynamic sidebars and sidebar locations. Sidebar locations are in a fixed location and can be assigned different dynamic sidebars depending on template or page. Make sure the sidebar you are editing the background options for is assigned to the “Secondary Header Sidebar” location for that template or page. The function that outputs the background options for the sidebars is called enlightenment_unlimited_sidebars_print_css() and can be found in core/functions/unlimited-sidebars.php.
Here’s how to get the tabs span the full width of the page:
@media (min-width: 992px) {
.layout-full-width .nav-tabs,
.layout-full-width .tab-content {
margin-left: -150px;
margin-right: -150px;
}
}
Keep in mind that 18 tabs is too much for the average person’s attention span, it’s bad UX regardless and should use some optimizing.
the mega menu option in smaller resolution (tablet and phone), has a fixed height window which means that some links are obscured.
This is not true. The mega menu does not have a fixed height on either resolution. Check the demo to see for yourself. If this happens you probably tweaked it like that yourself.