ul.menu 
{
list-style-type: none;
margin: 0;
padding: 0;
display: flex;
flex-direction: row; /* ou bien column pour vertical */
flex-wrap: wrap;
justify-content: flex-start; /* ou bien center ou bien flex-end */
background-color: #ee4b42;
border: 500px;
}

ul.menu li a
{
text-align: left;
text-decoration: none;
padding: .75em 1.25em;
display: block;
color: black;
background-color: #ee4b42;
}

ul.menu li a:hover
{
background-color: #be0900;
transition: background .2s ease-in-out;
}

h2
{
    text-align : center;
}