I have tried so many different ways to make h1 and h2 center aligned. I have managed to make them centered horizontally, not sure why it won't work for vertical alignment. They also move when navbar shows. I really don't know how to fix it. I tried "display: table-cell; vertical-align: middle;" when i searched some other answers, still did not work.
.bg-title{
  color: white;
  font-family: 'Bungee Inline', cursive;
  font-size: 100pt;
  text-align:center;
  vertical-align:middle;  
}
.secd-title{
  color: white;
  font-family: 'Candal', sans-serif;
  text-align:right;
  margin-right: 2.5em;
}
.bg-title-wrap{
  display: flex;
  flex-direction: column;
  position: relative;
  justify-items: center;
  align-items: center;
}<!doctype html>
<html class="no-js" lang="en" dir="ltr">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="x-ua-compatible" content="ie=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Foundation for Sites</title>
    <link rel="stylesheet" href="css/foundation.css">
    <link rel="stylesheet" href="css/app.css">
  </head>
<body>
  <!-- <div class="backGround"></div>-->
  <header class="header">
    <nav id = "main-menu">
      <div class="title-bar-right nav-wrap" data-responsive-toggle="main-nav" data-hide-for="large-dropdown">
        
        <div class="title-bar-title nav-title">Menu</div>
        <button class="menu-icon" type="button" data-toggle="main-nav"></button>
      </div>
      
      <div class="top-bar" id="main-nav" data-animate="hinge-in-from-top spin-out">
        <div class="top-bar-right">
          <ul class="vertical large-vertical menu" data-responsive-menu="drilldown large-dropdown">
            <li class="home"><a href="#">HOME</a></li>
            <li><a href="#">BUY CANNABIS</a></li>
            <li><a href="#">STORES</a></li> 
            <li><a href="#">ABOUT US</a></li>
            <li><a href="#">CONTACT</a></li>
            <li><a href="#">SUBSCRIBE</a></li>
          </ul>
        </div>
      </div>
    </nav>
  </header>
  <main>
    <div class="bg-title-wrap">
    <h1 class="bg-title">store name</h1>
    <h2 class="secd-title">CANNABIS CO.</h2>
    </div>
  </main>
    <script src="js/vendor/jquery.js"></script>
    <script src="js/vendor/what-input.js"></script>
    <script src="js/vendor/foundation.js"></script>
    <script src="js/app.js"></script>
  </body>
</html> 
     
    