title: Padding causes horizontal scroll - it increases the width
body: <p>Please look at this code:</p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
  &lt;style type="text/css"&gt;
  html, body{
  width:100%;
  height:100%;
  margin:0px;
  }
  
  #header{
  width:100%;
  height:100px;
  position:fixed;
  display:inline-block;
  background-color:red;
  padding:0 10px 10px 10px;
  }
  &lt;/style&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;div id="header"&gt;
           &lt;div id="header-container"&gt;
           &lt;/div&gt;
      &lt;/div&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>here is the <a href="http://jsfiddle.net/3hVvW/2/" rel="noreferrer">demo</a> .
  The <code>header</code> must have 100% width and 10px padding from left,right and bottom. please look at this picture</p>
  
  <p><img src="https://i.stack.imgur.com/mo3Xh.png" alt="enter image description here"></p>
  
  <p>this is the layout of <code>#header</code> by firebug. as you can see the right padding is not in the image because the 10px padding is added to the <code>#header</code> width (you can test it). how can I set 100% width for <code>#header</code> and 10px padding for left,right and bottom without increasing the width?</p>