/* =========================
   RESET
========================= */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* =========================
   BASE
========================= */
body {
    font-family: "Segoe UI", Arial, sans-serif;
    background-color: #f1f3f6;
    color: #2c2c2c;
    line-height: 1.6;
}

/* =========================
   HEADER
========================= */
.header {
    background-color: #1f3556;
    color: white;
    padding: 25px 20px;
    text-align: center;
    position: relative;
}

.header h1 {
    font-size: 26px;
    font-weight: 600;
}

/* Bouton retour */
.retour {
    position: absolute;
    left: 20px;
    top: 50%;
    transform: translateY(-50%);
    color: white;
    text-decoration: none;
    font-size: 14px;
    padding: 6px 14px;
    border: 1px solid rgba(255,255,255,0.7);
    border-radius: 6px;
    transition: all 0.3s ease;
}

.retour:hover {
    background-color: white;
    color: #1f3556;
}

/* =========================
   NAVIGATION
========================= */
nav {
    background-color: #2f4f73;
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
}

nav ul li a {
    padding: 14px 22px;
    display: block;
    color: white;
    text-decoration: none;
    font-size: 14px;
    transition: background-color 0.3s;
}

nav ul li a:hover {
    background-color: #1f3556;
}

/* =========================
   CONTENU
========================= */
main {
    max-width: 900px;
    margin: 40px auto;
    padding: 0 20px;
}

/* =========================
   CARTES (SECTIONS)
========================= */
section {
    background-color: white;
    padding: 25px 30px;
    margin-bottom: 35px;
    border-radius: 8px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.08);
}

/* Titres */
section h2 {
    font-size: 20px;
    color: #1f3556;
    margin-bottom: 15px;
    padding-bottom: 8px;
    border-bottom: 2px solid #1f3556;
}

/* Texte */
section p {
    margin-bottom: 10px;
    font-size: 15px;
}

/* Listes */
section ul {
    margin-left: 20px;
}

section ul li {
    margin-bottom: 8px;
}

/* =========================
   FOOTER
========================= */
footer {
    background-color: #1f3556;
    color: white;
    text-align: center;
    padding: 15px;
    font-size: 13px;
}

/* =========================
   RESPONSIVE (MOBILE)
========================= */
@media (max-width: 768px) {
    nav ul {
        flex-wrap: wrap;
    }

    .retour {
        position: static;
        display: inline-block;
        margin-bottom: 10px;
        transform: none;
    }

    .header {
        padding: 20px;
    }
}