title: How to reduce default margin of hr tag?
body: <p>I can increase the default margin of a <code>hr</code> tag. But I can't reduce the margin of <code>hr</code> to zero. All I need is just horizontal line with zero top and bottom margin</p>
  
  <pre><code>&lt;p&gt;This is header&lt;/p&gt;
  &lt;hr class="divider" /&gt;
  &lt;p&gt;This is content. I just want to reduce the margin of hr tag&lt;/p&gt;
  </code></pre>
  
  <pre class="lang-css prettyprint-override"><code>hr.divider
  { 
     margin-top: 0em;
     margin-bottom: 0em;
     border-width: 2px;
  } 
  </code></pre>
  
  <p>See also <a href="https://jsfiddle.net/rajagopalx/f6hhcdfq/" rel="noreferrer">this jsfiddle</a>.</p>