ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #333333;
}

ul li {
    float: left;
}

ul li a {
    display: block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

ul li a:hover {
    background-color: #111111;
}
footer {
    background-color: #f1f1f1;
    text-align: center;
    padding: 8px;
}
header {
    background-color: #f1f1f1;
    text-align: center;
    padding: 10px;
}

.flex-container {
    display: flex;
    flex-direction: row;
}
.container div {
    background-color: #f1f1f1;
    margin: 10px;
    padding: 20px;
    font-size: 30px;
}
.container {
    display: flex;
    flex-direction: column-reverse;
}
.menu ul>li {
    display: block;
    float: left;
}

.menu li:hover>a{
    background: #555;
    color: #fff;
}
.dropdown{
    /*  display: none;*/
    display: block;
    opacity: 0;
    background: #ccc;
    

    transition: all 0.3s ease;
}

.menu li:hover>ul{
    top: 47px;
    left: 0;
    opacity: 1;
}