Customize the weight of Blog page

I would like to customize the weight of Blog page so that it’s more centered to suit my website.

https://thi-tran.info/wp-content/uploads/2016/05/error-1.png”

As in the picture above, I would like the weight to be neater as the red lines showed.

My website is: https://thi-tran.info/
This is the code from content-single.php which I think that it’s related to this page.

<?php
$sidebar_select = get_post_meta($post->ID, 'sidebar_select', true);
if ($sidebar_select == 'right') {
    $sidebar_select_aside_classes = '';
    $sidebar_select_content_classes = '';
} else {
    $sidebar_select_aside_classes = 'col-sm-pull-20';
    $sidebar_select_content_classes = 'col-sm-push-15';
}
if (empty($sidebar_select) || ($sidebar_select == 'none')) {
?>
    <div <?php post_class('content row'); ?>>
        <div class="col-xs-12 content-column">
            <div class="row single_meta">
                <div class="col-sm-8">
                    <p>
                    <?php
                    _e('Posted by ', 'nimbus');
                    the_author_posts_link();
                    _e(' on ', 'nimbus');
                    the_time(get_option( 'date_format' ));
                    ?></p>
                </div>
                <div class="col-sm-4">
                    <?php if (comments_open()) { ?><p class="text-right"><a href="<?php the_permalink(); ?>#comments" ><?php comments_number( 'No comments', 'One comment', '% comments' ); ?></a></p><?php } ?>
                </div>
            </div>
            <?php
            the_content();
            nimbus_clear();
            get_template_part( 'parts/wp_link_pages');
            get_template_part( 'parts/tax_tags');
            comments_template();
            get_template_part( 'parts/single_post_nav');
            ?>
        </div>
    </div>
<?php
} else {
?>
    <div <?php post_class('content row'); ?>>

        <div class="col-sm-8 content-column <?php echo $sidebar_select_content_classes; ?>">
            <div class="row single_meta">
                <div class="col-sm-8">
                    <p>
                    <?php
                    _e('Posted by ', 'nimbus');
                    the_author_posts_link();
                    _e(' on ', 'nimbus');
                    the_time(get_option( 'date_format' ));
                    ?></p>
                </div>
                <div class="col-sm-4">
                    <?php if (comments_open()) { ?><p class="text-right"><a href="<?php the_permalink(); ?>#comments" ><?php comments_number( 'No comment', 'One comment', '% comments' ); ?></a></p><?php } ?>
                </div>
            </div>
            <?php
            the_content();
            nimbus_clear();
            get_template_part( 'parts/wp_link_pages');
            get_template_part( 'parts/tax_tags');
            comments_template();
            get_template_part( 'parts/single_post_nav');
            ?>
        </div>
        <div class="col-sm-4 <?php echo $sidebar_select_aside_classes; ?>">
            <?php
            get_sidebar();
            ?>
        </div>
    </div>
<?php
}
?>