body{
    background-image: url(https://media.istockphoto.com/photos/vintage-old-paper-textured-background-picture-id854468942    ) ;
    background-size: 100%;
    
}

h1{
    text-align: center;
    font-size: 60px;
}


img:hover   {
    transform: scale(1.5);
    transition: 2s;
}

.boutonmenuprincipal {
    background-color: #37e8e8;
    color: white;
    border: none;
    cursor: pointer;
    padding: 25px;
}

.boutonmenuprincipal:hover {
    background-color: #dcdcdc;
    transition: 500ms;
}

.dropdown {
    position: relative;
    float: right;
}

.dropdown-child {
    display: none;
    background-color: #f28c8c;
}
    
.dropdown-child a {
    color: white;
    padding: 20px;
    text-decoration: none;
    display: block;
}

.dropdown:hover .dropdown-child {
    display: block;
}

.dropdown-child a:hover{
    background-color: #0fc41e ;
}