Why is there so much space between <h3> and <p>

I don't get it. Why is there so much space between "title" and "text"? Please take a look at this code:

 <h3 style="background:#000">Title</h3>
        <p class="d" style="background:#000">
       Text Text Text Text Text Text Text Text Text Text Text 
        </p>

There are absolutely no other styles applied to those two elements, but still, there are so much unused space. Anyone have an idea here?