Linking display of hamburger icon with custom breakpoint

Question

In my foundation_and_overrides.scss , I have changed the topbar-breakpoint to a particular px width. I'd like to display the hamburger icon when the width is less than the breakpoint.

Right now it removes the menu and leaves it blank until I hit $small-range . I'm not sure where to edit within the foundation_and_overrides.scss to display the hamburger icon/menu when it hits the new breakpoint.

SCSS

$topbar-breakpoint: 1225px; // Change to 9999px for always mobile layout
$topbar-media-query: "only screen and (min-width: #{$topbar-breakpoint})" !default;

HTML

<div class="fixed header" style="border-bottom: 1px solid #000;">
  <nav class="top-bar" data-topbar role="navigation">
    <ul class="title-area">
      <li class="name">
        <h1><a href="/"><img src="/assets/logo.png" alt="" id="logo-image"></a></h1>
      </li>

      <li class="toggle-topbar menu-icon"><a href="#"><span>Menu</span></a></li>
     </ul>

<section class="top-bar-section">
  <ul class="left">
    <li><a href='/programs'>Programs</li>
    <li><a href='/projects'>Projects</li>
  </ul>
</section>
</nav>
</div>