What is the space between the sections in HTML?
<p>I've got this HTML structure:</p>

<pre><code>&lt;body cz-shortcut-listen="true"&gt;
    &lt;div id="panels"&gt;
        &lt;section id="sect0" name="lvl0"&gt;
            &lt;div id="divLvel0" class="level zero"&gt;
                &lt;h2&gt;top&lt;nav&gt;&lt;ul&gt;&lt;li&gt;&lt;a href="#sect1"&gt;Languages&lt;/a&gt;&lt;/li&gt;&lt;li&gt;&lt;a href="#sect2"&gt;Proficiency&lt;/a&gt;&lt;/li&gt;&lt;li&gt;&lt;a href="#sect3"&gt;Milestones&lt;/a&gt;&lt;/li&gt;&lt;li&gt;&lt;a href="#sect4"&gt;Details&lt;/a&gt;&lt;/li&gt;&lt;/ul&gt;&lt;/nav&gt;&lt;/h2&gt;
            &lt;/div&gt;
        &lt;/section&gt;
        &lt;section id="sect1" name="lvl1"&gt;
            &lt;div id="divLvel1" class="level one"&gt;
                &lt;div id="panel_lvl1"&gt;
                    &lt;h2&gt;Languages&lt;/h2&gt;
                &lt;/div&gt;
            &lt;/div&gt;
        &lt;/section&gt;
        &lt;section id="sect2" name="lvl2"&gt;
        &lt;/section&gt;
        &lt;section id="sect3" name="lvl3"&gt;
            &lt;div id="divLvel3" class="level three"&gt;
                &lt;div id="panel_lvl3"&gt;
                    &lt;h2&gt;Milestones&lt;/h2&gt;
                    &lt;div id="chart3"&gt;
                    &lt;/div&gt;
                &lt;/div&gt;
            &lt;/div&gt;
        &lt;/section&gt;
        &lt;section id="sect4" name="lvl4"&gt;
            &lt;div id="divLvel4" class="level four"&gt;
                &lt;div id="panel_lvl4"&gt;
                    &lt;h2&gt;Details&lt;/h2&gt;
                    &lt;div id="chart4"&gt;
                    &lt;/div&gt;
                &lt;/div&gt;
            &lt;/div&gt;
        &lt;/section&gt;
    &lt;/div&gt;
&lt;/body&gt;
</code></pre>

<p><a href="https://jsfiddle.net/thadeuszlay/Lkdo5xv3/2/" rel="nofollow">https://jsfiddle.net/thadeuszlay/Lkdo5xv3/2/</a></p>

<p>Every section touch each other directly, i.e. there is no additional element in between the sections. But somehow you can see a gap (the green background color) between each section. </p>

<p>I already set the padding and the margin of the body to zero. Also I replaced the sections with DIVs. But the gap is still there.</p>

<p>How do I get rid of the gap and make each section touch other without a gap between them?</p>