* {
    box-sizing: border-box;
}

body {
    font-family: Arial, Helvetica, sans-serif;
}


/* ------------------------------ */
/*   HEADER                       */
/* ------------------------------ */

header {
    background-color: #666;
    padding: 5px;
    text-align: center;
    font-size: 35px;
    color: white;
}


/* ------------------------------ */
/*   NAVIGATION                   */
/* ------------------------------ */

nav {
    float: left;
    width: 20%;
    height: 680px;
    background: #ccc;
    padding: 20px;
}

nav ul {
    list-style-type: none;
    padding: 0;
}

nav button {
    width: 100%;
}


/* ------------------------------ */
/*   ARTICLE (PARTIE CENTRALE)    */
/* ------------------------------ */

article {
    float: left;
    padding: 20px;
    width: 80%;
    background-color: #f1f1f1;
    height: 680px;
}


/* ------------------------------ */
/*   SECTION CLEARFIX             */
/* ------------------------------ */

section::after {
    content: "";
    display: table;
    clear: both;
}


/* ------------------------------ */
/*   FOOTER                       */
/* ------------------------------ */

footer {
    background-color: #777;
    padding: 10px;
    text-align: center;
    color: white;
}


/* ------------------------------ */
/*   TABLEAUX (Page 2)            */
/* ------------------------------ */

table {
    font-family: arial, sans-serif;
    border-collapse: collapse;
    width: 80%;
}

td, th {
    border: 1px solid #dddddd;
    text-align: left;
    padding: 8px;
}

tr:nth-child(even) {
    background-color: #dddddd;
}


/* ------------------------------ */
/*   RESPONSIVE DESIGN            */
/* ------------------------------ */

@media (max-width: 600px) {
    nav, article {
        width: 100%;
        height: auto;
    }
}