Bootstrap Dark Header

by Grobbert

HTML

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Untitled</title>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/css/bootstrap.min.css">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
    <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Bitter:400,700">
    <link rel="stylesheet" href="assets/css/style.css">
</head>

<body>
    <div>
        <div class="header-dark">
            <nav class="navbar navbar-dark navbar-expand-md navigation-clean-search">
                <div class="container"><a class="navbar-brand" href="#">The X-Files Company</a><button class="navbar-toggler" data-toggle="collapse" data-target="#navcol-1"><span class="sr-only">Toggle navigation</span><span class="navbar-toggler-icon"></span></button>
                    <div class="collapse navbar-collapse"
                        id="navcol-1">
                        <ul class="nav navbar-nav">
                            <li class="nav-item" role="presentation"><a class="nav-link" href="#">Link</a></li>
                            <li class="dropdown"><a class="dropdown-toggle nav-link dropdown-toggle" data-toggle="dropdown" aria-expanded="false" href="#">Dropdown </a>
                                <div class="dropdown-menu" role="menu"><a class="dropdown-item" role="presentation" href="#">First Item</a><a class="dropdown-item" role="presentation" href="#">Second Item</a><a class="dropdown-item" role="presentation" href="#">Third Item</a></div>
                            </li>
                        </ul>
                        <form class="form-inline mr-auto" target="_self">
                            <div class="form-group"><label for="search-field"><i class="fa fa-search"></i></label><input class="form-control search-field" type="search" name="search"...

CSS

.header-dark {
  background:url('https://cdn.pixabay.com/photo/2015/10/12/14/59/milky-way-984050_960_720.jpg') #444;
  background-size:cover;
  padding-bottom:80px;
}

@media (min-width:768px) {
  .header-dark {
    padding-bottom:120px;
  }
}

.header-dark .navbar {
  background:transparent;
  padding-top:0;
  padding-bottom:0;
  color:#fff;
  border-radius:0;
  box-shadow:none;
  border:none;
}

@media (min-width:768px) {
  .header-dark .navbar {
    padding-top:.75rem;
    padding-bottom:.75rem;
  }
}

.header-dark .navbar .navbar-brand {
  font-weight:bold;
  color:inherit;
}

.header-dark .navbar .navbar-brand:hover {
  color:#f0f0f0;
}

.header-dark .navbar .navbar-collapse span {
  margin-top:5px;
}

.header-dark .navbar .navbar-collapse span .login {
  color:#d9d9d9;
  margin-right:.5rem;
  text-decoration:none;
}

.header-dark .navbar .navbar-collapse span .login:hover {
  color:#fff;
}

.header-dark .navbar .navbar-toggler {
  border-color:#747474;
}

.header-dark .navbar .navbar-toggler:hover, .header-dark .navbar-toggler:focus {
  background:none;
}

.header-dark .navbar .navbar-toggler {
  color:#eee;
}

.header-dark .navbar .navbar-collapse, .header-dark .navbar .form-inline {
  border-color:#636363;
}

@media (min-width: 992px) {
  .header-dark .navbar.navbar .navbar-nav .nav-link {
    padding-left:1.2rem;
    padding-right:1.2rem;
  }
}

.header-dark .navbar.navbar-dark .navbar-nav .nav-link {
  color:#d9d9d9;
}

.header-dark .navbar.navbar-dark .navbar-nav .nav-link:focus, .header-dark .navbar.navbar-dark .navbar-nav .nav-link:hover {
  color:#fcfeff !important;
  background-color:transparent;
}

.header-dark .navbar .navbar-nav > li > .dropdown-menu {
  margin-top:-5px;
  box-shadow:0 4px 8px rgba(0,0,0,.1);
  background-color:#fff;
  border-radius:2px;
}

.header-dark .navbar .dropdown-menu .dropdown-item:focus, .header-dark .navbar .dropdown-menu .dropdown-item {
  line-height:2;
  font-size:14px;
  color:#37434d;
}

.header-dark .navbar...