fixing margins from navbar <p>In my recent project, I adjust the style for this header:</p> <pre><code>&lt;header&gt; &lt;ul&gt; &lt;li&gt;&lt;a href="#" class="title"&gt;Loja&lt;/a&gt;&lt;/li&gt; &lt;/ul&gt; &lt;ul class="right"&gt; &lt;li&gt;&lt;a href="#" class="user"&gt;username&lt;/a&gt;&lt;/li&gt; &lt;li&gt;&lt;a href="#"&gt;logout&lt;/a&gt;&lt;/li&gt; &lt;/ul&gt; &lt;/header&gt; </code></pre> <p>as that:</p> <pre><code>header { top: 0; left: 0; background-color: #333; width:100%; } header:after{ visibility: hidden; display: block; font-size: 0; content: " "; clear: both; height: 0; } </code></pre> <p>jsfiddle: <a href="https://jsfiddle.net/klebermo/ch6gtj3p/7/" rel="nofollow">https://jsfiddle.net/klebermo/ch6gtj3p/7/</a></p> <p>but with this, I got a small space between the edge of the browser's window and the navbar. What I can do to remove this space?</p>