To achieve this, you can arrange the layout to wrap the articles around the sidebar instead of creating two columns by moving the sidebar inside the archives section.
<div class="shrinkwrap">
<section>
<section class="archives">
<aside class="blog-sidebar">
</aside>
<article>
</article>
<article>
</article>
<article>
</article>
</section>
</section>
</div>
Next, in the CSS code, you can adjust the sidebar to float left and remove the "position: relative".
aside {
float: left;
/* position: relative; */
}
Lastly, you should eliminate the "float: left" from the article tag.
article {
/* float: left; */
}
This method may not be perfect at first, but it's a way to handle the positioning. Further adjustments can be made for perfection :)