title: I'm trying to use hamburger menu on bulma css, but it doesn't work. What is wrong?
body: <p>I'm new on bulma css <a href="http://bulma.io/" rel="noreferrer">http://bulma.io/</a></p>
  
  <p>I'm trying to use hamburger menu for mobile user.
  I just followed instruction on this page: <a href="http://bulma.io/documentation/components/nav/" rel="noreferrer">http://bulma.io/documentation/components/nav/</a></p>
  
  <p>But it doesn't work. What should I add ?</p>
  
  <p><strong>Actually, I can see hamburger menu, but it doesn't work when I am click it.</strong></p>
  
  <p>Thank you.</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
      &lt;head&gt;
          &lt;meta charset="utf-8"&gt;
          &lt;meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1"&gt;
          &lt;title&gt;test&lt;/title&gt;
  
          &lt;link rel="stylesheet" href="css/bulma.min.css"&gt;
          &lt;link rel="stylesheet" href="css/custom.css"&gt;
      &lt;/head&gt;
      &lt;body&gt;
          &lt;section class="hero is-fullheight is-primary is-bold"&gt;
              &lt;!-- Hero header: will stick at the top --&gt;
              &lt;div class="hero-head"&gt;
                  &lt;header class="nav"&gt;
                      &lt;div class="container"&gt;
                          &lt;div class="nav-left"&gt;
                              &lt;a class="nav-item" href="/"&gt;
                                  &lt;img src="img/logo.png" alt="Logo"&gt;
                              &lt;/a&gt;
                          &lt;/div&gt;
                          &lt;span class="nav-toggle"&gt;
                              &lt;span&gt;&lt;/span&gt;
                              &lt;span&gt;&lt;/span&gt;
                              &lt;span&gt;&lt;/span&gt;
                          &lt;/span&gt;
                          &lt;div class="nav-right nav-menu"&gt;
                              &lt;a class="nav-item" href="/about"&gt;
                                  About
                              &lt;/a&gt;
                              &lt;a class="nav-item" href="/path"&gt;
                                  Path
                              &lt;/a&gt;
                              &lt;a class="nav-item" href="/blog"&gt;
                                  Blog
                              &lt;/a&gt;
                          &lt;/div&gt;
                      &lt;/div&gt;
                  &lt;/header&gt;
              &lt;/div&gt;
              &lt;!-- Hero content: will be in the middle --&gt;
              &lt;div class="hero-body"&gt;
                  &lt;div class="container has-text-centered"&gt;
                  &lt;/div&gt;
              &lt;/div&gt;
          &lt;/section&gt;
      &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>