Aditya Pandey

We provide support only theme that is accessible from WP.org.
Your theme is commercial theme and WordPress doesn’t provide support for commercial products.
https://codex.www.ads-software.com/Forum_Welcome#Commercial_Products

Ask your vendor for theme support.

First off, setup Child Theme.
Then copy and paste content of your index.php from parent theme to home.php in child theme folder (create file with this name).

And then find and remove following code form home.php of child theme :

<!--content-->

		<div class="row" id="content_container">

	<!--left col--><div class="eight columns">

		<div id="left-col">

			<?php get_template_part( 'loop', 'index' ); ?>

	</div> <!--left-col end-->
</div> <!--column end-->

<?php get_sidebar(); ?>

</div>
<!--content end-->

It is called z-index. Use firebug to quickly identify selectors. And always use child themes or plugins like Custom CSS Manager to keep your modifications safe from theme updates.

I can’t find the issue with dropdown on your site. Can you please explain/screenshot which part of site have that issue?

Great.

Can you give me screenshot about this ‘space’, because I can’t find it.

Can you me link to your site?

We provide support for theme that is available in WordPress Theme Repository.

Contact your theme vendor for support.

What’s your site URL?
Generally, it’ll automatically appear after it reached the limit. The limit you specified at your site’s “Dashboard> Setting> Reading> Blog pages show at most :“.

First of all, I didn’t got a single point what you’re trying to say.
Secondly, it looks like you’re in wrong section or maybe wrong forum (I called up a Mod to look into this).

Put a slash before image location.
Corrected code:

<?php if ( ! $graphene_settings['hide_return_top'] ) : ?>
            <li class="menu-item return-top"><a href="#"><img src="/wp-content/uploads/2013/05/arrow-top.jpg" alt="to top" title="Return to top" /></a></li>
            <?php endif; ?>

I personally recommend this theme: https://www.ads-software.com/extend/themes/stitch

First of setup Child Theme or use plugin like Custom CSS Manager.
Then add following code in it:

#content {
      width: 900px;
}

Get Firebug to quickly identify selectors.
Read this nice article on how to use Firebug: https://www.studiopress.com/tips/using-firebug.htm

And for keeping your modification safe from theme updates, always use Child Themes.

You need to edit Category Template.
Find and change it as required.

Always post code in backticks otherwise forum parser will break the code. That is happened in your case.

Please re-post code inside backticks.