* {
    margin: 0px;
    padding: 0px;
    font-family: Avenir, sans-serif;
}

nav {
    width: 100%;
    margin: 0 auto;
    background-color: rgba(100, 100, 100, 0.5);
    position: sticky;
    top: 0px;
    border-color: transparent;
    border-bottom: black;

}

nav ul {
    list-style-type: none;
}

nav ul li {
    float: left;
    width: 25%;
    text-align: center;
    position: relative;
}

nav ul::after {
    content: "";
    display: table;
    clear: both;
}

nav a {
    display: block;
    text-decoration: none;
    color: goldenrod;
    border-bottom: 2px solid transparent;
    padding: 10px 0px;
}

nav a:hover {
    color: goldenrod;
    border-bottom: 2px solid gold;
}

.sous {
    display: none;
    box-shadow: 0px 1px 2px #CCC;
    background-color: #444;
    position: absolute;
    width: 100%;
    z-index: 1000;
}

nav>ul li:hover .sous {
    display: block;
}

.sous li {
    float: none;
    width: 100%;
    text-align: left;
}

.sous a {
    padding: 10px;
    border-bottom: none;
}

.sous a:hover {
    border-bottom: none;
    background-color: RGBa(200, 200, 200, 0.1);
}

.deroulant>a::after {
    content: " ▼";
    font-size: 12px;
}

.conteneur {
    margin: 50px 20px;
    height: 1500px;
}