navbar bootstrap sous le contenu de la page

AaFrederic Husson
Les bases HTML/CSS

Bonjour,

je rencontre un soucis avec la navbar bootstrap sur mobile et tablette
Le menu déroulant se retrouve sous le contenu de la page

voici mon css:

@import url('https://fonts.googleapis.com/css?family=Open+Sans');
@import url('https://fonts.googleapis.com/css?family=Coming+Soon');

body {
    background-color: #000000;
    color: white;
    font-family: 'Open Sans', sans-serif;

}
h3 {
    font-weight: bold;
    font-size: 50px;
    font-family: 'Coming Soon', cursive;
}
.navbar {
    background-color: #ea0071;
    border-radius: 0px;
    height: 20px;
    border: 0px;
}
.content_navbar {
    background-color: #ea0071;
    height: 50px;
}

section {
    background: url("/images/background.jpg") no-repeat right;
    min-height: 1184px;
}
.navbar-inverse .navbar-nav > li:first-child {
    border-right: 0px;
}
.navbar-inverse .navbar-nav > li > a:hover {
    background-color: #9c004b;
    color: white;
    border-right: 1px solid white;
}
.navbar-inverse .navbar-nav > li > a,
.navbar-inverse .navbar-nav > li > a:focus {
    color: white;
    border-right: 1px solid white;
}
.navbar-inverse .navbar-nav > li:first-child > a,
.navbar-inverse .navbar-nav > li:first-child > a:hover {
    background-color: #ea0071;
    cursor: default;
    border: 0px;
}
@media (min-width: 1200px) {
    .navbar-inverse .navbar-nav > li {
        width: 150px;
        text-align: center;
    }

    .logo {
        width: 250px;
        height: 250px;
        background-color: #ea0071;
        border-bottom-right-radius: 5px;
        border-bottom-left-radius: 5px;
    }

    .img_logo {
        width: 240px;
        height: 240px;
        position: relative;
        top: 5px;
        right: 3px;
    }

    .navbar-inverse .navbar-nav > li:first-child {
        width: 250px;
    }
}

.navbar-inverse .navbar-toggle:focus {
    background-color: #ea0071;
}

@media (max-width: 1200px) {
    .navbar-header {
        float: none;
    }
    .navbar-left,.navbar-right {
        float: none !important;
    }
    .navbar-toggle {
        display: block;
    }
    .navbar-collapse {
        border-top: 1px solid transparent;
        box-shadow: inset 0 1px 0 rgba(255,255,255,0.1);
    }
    .navbar-fixed-top {
        top: 0;
        border-width: 0 0 1px;
    }
    .navbar-collapse.collapse {
        display: none!important;
    }
    .navbar-nav {
        float: none!important;
        margin-top: 7.5px;
    }
    .navbar-nav>li {
        float: none;
    }
    .navbar-nav>li>a {
        padding-top: 10px;
        padding-bottom: 10px;
    }
    .collapse.in{
        display:block !important;
    }
}
footer {
    color: #818181;
    height: 100px;
}

.index {
    padding-top: 250px;
}
footer a, footer a:hover {
    color: #818181;

et le contenu de ma page:

<!DOCTYPE html>
<html lang="fr">
<head>
    <meta charset="UTF-8">
    <link type="text/css" rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css">
    <link type="text/css" rel="stylesheet" href="css/style.css">
    <title></title>
</head>
<body>

<header>

    <div class="content_navbar">
        <div class="container">
            <!-- start of the bootstrap navigation bar -->
            <nav class="navbar navbar-inverse">
                <div class="container-fluid">
                    <div class="navbar-header">
                        <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
                            <span class="sr-only">Toggle navigation</span>
                            <span class="icon-bar"></span>
                            <span class="icon-bar"></span>
                            <span class="icon-bar"></span>
                        </button>
                    </div>
                    <div id="navbar" class="navbar-collapse collapse">
                        <ul class="nav navbar-nav">
                            <li class="logo"><img src="/images/logo.jpg" class="img_logo"></li>
                            <li><a href="#">Accueil</a></li>
                            <li><a href="#">Notre Concept</a></li>
                            <li><a href="#">Le Programme</a></li>
                            <li><a href="#" id="contacter">Nous contacter</a></li>
                        </ul>
                    </div>
                </div>
            </nav>
        </div>
        <!-- end of the bootstrap navigation bar -->

    </div>
</header>

<section class="container index">
    <div class="col-sm-offset-1 col-sm-11">
    <h3>Samedi 12 Mai 2018<br><br>
    Salle Bla Bla 34200 Sète<br><br>
    Avec la participation de<br><br>
    Jean-Charles WERRY</h3>
    </div>

</section>

<footer class="container">
    <div class="col-sm-o6">
        &copy; 2018 La journée de la mode par <a href="http://www.web-soluces.com">web-soluces.com</a>
    </div>
</footer>

<!-- jQuery -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<!-- Javascript of Bootstrap -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script>

</body>
</html>

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