`justify-content` property not working on nested flexbox
<p>I'm quite new to HTML and CSS and I've encountered a problem with the menu I'm currently coding. </p>

<p>I'd like to make a menu using nesting flexbox. It's getting close to what I want but for a reason I cannot understand, the <code>justify-content</code> inside the children flexbox doesn't seem to apply... </p>

<p>Here is my code : </p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-css lang-css prettyprint-override"><code>header {
  display: inline-flex;
  height: 90px;
  align-items: center;
  justify-content: flex-start;
}
.avatar {
  display: inline-flex;
  height: inherit;
  width: 200px;
  background-color: #00D717;
  align-items: center;
  justify-content: space-around;
}
.avatar h1 {
  font-size: 13px;
  text-transform: uppercase;
  color: white;
}
.resteHeader {
  display: inline-flex;
  height: inherit;
  justify-content: flex-start;
  align-items: center;
}
.resteHeader nav {
  display: inline-flex;
  height: inherit;
  justify-content: space-around;
  align-items: center;
}
.resteHeader nav ul {
  display: inline-flex;
  height: inherit;
  justify-content: space-between;
  align-items: center;
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;header&gt;
  &lt;div class="avatar"&gt;
    &lt;img src="img/avatar.png"&gt;
    &lt;h1&gt;Hoang Nguyen&lt;/h1&gt;
  &lt;/div&gt;
  &lt;div class="resteHeader"&gt;
    &lt;nav&gt;
      &lt;ul&gt;
        &lt;li&gt;
          &lt;a href="#"&gt;
            &lt;img src="img/silhouette.png" alt=""&gt;
          &lt;/a&gt;
        &lt;/li&gt;
        &lt;li&gt;
          &lt;a href="#"&gt;
            &lt;img src="img/bulle.png" alt=""&gt;
          &lt;/a&gt;
        &lt;/li&gt;
        &lt;li&gt;
          &lt;a href="#"&gt;
            &lt;img src="img/cloche.png" alt=""&gt;
          &lt;/a&gt;
        &lt;/li&gt;
      &lt;/ul&gt;
    &lt;/nav&gt;
    &lt;img class="logo" src="img/logo.png" alt=""&gt;
    &lt;form&gt;
      Type sor search
      &lt;input type="text"&gt;
      &lt;img src="img/loupe.png" alt=""&gt;
    &lt;/form&gt;
  &lt;/div&gt;
&lt;/header&gt;</code></pre>
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</p>

<p>Thanks for your help ! </p>