WordPress Pagination Shows Same Page at all page numbers

I have just Created a New WordPress Theme. But i am failed in Pagination Step. I have created it but it is Showing Same Posts on All Paged Numbers.. Here are My Codes…

Functions.php

function pagination($pages = '', $range = 4)
{
     $showitems = ($range * 2)+1;  

     global $paged;
     if(empty($paged)) $paged = 1;

     if($pages == '')
     {
         global $wp_query;
         $pages = $wp_query->max_num_pages;
         if(!$pages)
         {
             $pages = 1;
         }
     }   

     if(1 != $pages)
     {
         echo "<div class=\"pagination\"><span>Page ".$paged." of ".$pages."</span>";
         if($paged > 2 && $paged > $range+1 && $showitems < $pages) echo "<a href='".get_pagenum_link(1)."'>&laquo; First</a>";
         if($paged > 1 && $showitems < $pages) echo "<a href='".get_pagenum_link($paged - 1)."'>&lsaquo; Previous</a>";

         for ($i=1; $i <= $pages; $i++)
         {
             if (1 != $pages &&( !($i >= $paged+$range+1 || $i <= $paged-$range-1) || $pages <= $showitems ))
             {
                 echo ($paged == $i)? "<span class=\"current\">".$i."</span>":"<a href='".get_pagenum_link($i)."' class=\"inactive\">".$i."</a>";
             }
         }

         if ($paged < $pages && $showitems < $pages) echo "<a href=\"".get_pagenum_link($paged + 1)."\">Next &rsaquo;</a>";
         if ($paged < $pages-1 &&  $paged+$range-1 < $pages && $showitems < $pages) echo "<a href='".get_pagenum_link($pages)."'>Last &raquo;</a>";
         echo "</div>\n";
     }
}

Style.css

` .pagination {
margin-left:25%;
clear:both;
padding:20px 0;
position:relative;
font-size:14px;
font-weight:bold;
line-height:18px;
}

.pagination span, .pagination a {
display:block;
float:left;
margin: 2px 2px 2px 0;
padding:6px 9px 5px 9px;
text-decoration:none;
width:auto;
color:#fff;
background:grey;
}

.pagination a:hover{
color:#fff;
background: #F9611E;
}

.pagination .current{
padding:6px 9px 5px 9px;
background: #F9611E;
color:#fff;
}`
And in Index.php Page Under the Posts Codes.

<?php query_posts('posts_per_page=7'); ?>
    <?php if (have_posts()) : ?>
    <?php while (have_posts()) : the_post(); ?>
<br><br>
<?php

$content = get_the_content();
$trimmed_content = wp_trim_words( $content, 50, '<a href="'. get_permalink() .'">... &nbsp;Read More</a>' );

?>

<a href="<?php the_permalink(); ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>">
<div class="title"><?php the_title(); ?></div></a>
<div class="date">Posted on <?php the_time('l,  F j, Y'); ?> at <?php the_time('g:i a'); ?></div>

<?php the_post_thumbnail(); ?>
<div class="content"><?php echo $trimmed_content; ?></div>
<br><br>
<hr class="phr"/><!-- //Single Post  -->

<?php endwhile; ?>

<?php endif; ?>
<hr class="phr">
    </div>
<div align="center"><!--//Pagination-->
<?php if (function_exists("pagination")) {
    pagination($additional_loop->max_num_pages);
} ?></div>

I have tried So much But i am watching same posts on Each Paged Posts.. To see my Page please visit this link.. https://jaylou.co/testwp/

Thanks