title: CSS - margin between elements without margin/padding?
body: <p>I've been working on my own CSS grid and found this website:</p>
  
  <p><a href="http://demo.select-themes.com/stockholm1/four-column-gallery/" rel="nofollow">http://demo.select-themes.com/stockholm1/four-column-gallery/</a></p>
  
  <p>Does anyone have any idea how it's achieved? Basically Portfolio elements have space between them, but there are no margins, paddings, anything I can think of:</p>
  
  <pre><code>&lt;article class="mix portfolio_category_2  mix_all" style=" "&gt;&lt;div class="image_holder standard_hover"&gt;&lt;span class="image"&gt;(...)&lt;/article&gt;
  
  2% margin (not sure where it comes from!)
  
  &lt;article class="mix portfolio_category_2  mix_all" style=" "&gt;&lt;div class="image_holder standard_hover"&gt;&lt;span class="image"&gt;(...)&lt;/article&gt;
  </code></pre>
  
  <p>I think it's Bootstrap but bootstrap's grid seems to have margins after all... These items have only bottom margins, but not right/left ones. How it's done?</p>