title: Space between fieldsets how to remove it
body: <p>I have created a simple login form. Here is a screenshot of the login form.</p>
  
  <p><img src="https://i.stack.imgur.com/mQQnT.png" alt="enter image description here"></p>
  
  <p>Here is the HTML code. I have used the 960 framework.</p>
  
  <pre><code>&lt;article class="container_12"&gt;   
          &lt;section id="login" class="grid_3"&gt;
                  &lt;form action="POST"&gt;
                      &lt;div id="loginheader"&gt;&lt;/div&gt;
                      &lt;fieldset class="logininputfields"&gt;
                          &lt;input type="text" name="username" placeholder="Username" autofocus&gt;
                          &lt;input type="password" name="password" placeholder="Password"&gt;
                      &lt;/fieldset&gt;
                      &lt;fieldset class="submitfield"&gt;
                          &lt;input type="submit" value="Log In"&gt;
                      &lt;/fieldset&gt;
                  &lt;/form&gt;
          &lt;/section&gt; 
      &lt;/article&gt;
  </code></pre>
  
  <p>and here is the CSS</p>
  
  <pre><code>#login
  {
      height: 330px;
  }
  
  #loginheader
  {
      background: black;
      height: 32px;
  }
  
  .logininputfields
  {
      background-color: #e5e5e5;
      padding-left: 24px;
      padding-bottom: 40px;
      height: 160px;
  }
  
  .logininputfields input[type="text"],input[type="password"]
  {
      background: #c8cbcc;
      margin-top: 30px;
      border:1px solid #ccc;
      color: #ededed;
      font-weight: 600;
      height: 30px;
      width: 170px;
  }
  
  .submitfield input[type="submit"]
  {
      background: #0099ff;
      border: 1px solid #ccc;
      height: 42px;
      width: 220px;
      font-weight: 600;
      font-size: large;
      color: white;
  }
  
  
  .submitfield input[type="submit"]:hover
  {
      background: rgba(0,154,255,0.60);
  }
  </code></pre>
  
  <p>I don't understand why there is a space between the submit button and the gray area. How can avoid it?</p>