<header>
<nav class="navbar navbar-fixed-top" style="
background: rgba(0, 0, 0, 0.30);
height: 10vh;
">
<div class="container-fluid">
<div class="navbar-header"><button type="button" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false" class="navbar-toggle collapsed"><span class="sr-only">Toggle navigation</span> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span></button> <a href="#" class="navbar-brand" style="padding: 0px 15px;"><img src="img/logo.jpg" style="height: 10vh;"></a></div>