/* Reset et boîte */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* Corps */
body {
    font-family: "Segoe UI", Arial, sans-serif;
    line-height: 1.6;
    color: #222;
    background: #fafafa;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Conteneur central */
.container {
    width: 90%;
    max-width: 1000px;
    margin: 0 auto;
}

/* En-tête */
header {
    background: #0d2b52;
    color: #fff;
    padding: 2rem 0;
}

header h1 {
    font-size: 2rem;
    line-height: 1.1;
}

.subtitle {
    opacity: 0.95;
    margin-top: 0.3rem;
    font-weight: 400;
}

/* Navigation */
nav {
    margin-top: 1rem;
}

nav a {
    color: #fff;
    text-decoration: none;
    margin-right: 1.2rem;
    font-weight: 500;
    transition: opacity 0.15s ease;
}

nav a:hover,
nav a:focus {
    text-decoration: underline;
    opacity: 0.9;
}

/* Présentation */
.about-content,
.hero-content {
    display: flex;
    gap: 2rem;
    align-items: center;
    justify-content: space-between;
}

.about-text {
    flex: 1 1 60%;
}

.about-photo,
.photo {
    flex: 0 0 220px;
    text-align: center;
}

.about-photo img,
.photo img {
    width: 220px;
    height: 220px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid #0d2b52;
    display: block;
    margin: 0 auto;
}

.photo-mail {
    margin-top: 0.8rem;
    font-size: 0.78rem;
    word-break: break-word;
}
.photo-mail a {
    color: #0d2b52;
    text-decoration: none;
    font-weight: 500;
}

.photo-mail a:hover {
    text-decoration: underline;
}

/* Sections générales */
section {
    padding: 3rem 0;
    background: #fff;
}

section + section {
    border-top: 1px solid rgba(0, 0, 0, 0.04);
}

/* Titres */
h2 {
    color: #0d2b52;
    margin-bottom: 1rem;
    font-size: 1.4rem;
}

/* Listes */
ul,
ol {
    margin-left: 1.25rem;
    padding-left: 0.5rem;
}

li {
    margin-bottom: 0.5rem;
}

/* Liens */
a {
    color: #0d2b52;
}

a.button,
.button {
    display: inline-block;
    padding: 0.6rem 1.2rem;
    background: #0d2b52;
    color: #fff;
    text-decoration: none;
    border-radius: 6px;
    transition: opacity 0.15s ease, transform 0.06s ease;
}

a.button:hover,
.button:hover {
    opacity: 0.95;
    transform: translateY(-1px);
}

/* Formule MathJax */
.formula {
    margin-top: 1rem;
    font-size: 1.05rem;
}

/* Pied de page */
footer {
    background: #0d2b52;
    color: #fff;
    text-align: center;
    padding: 1.5rem 0;
}

footer p {
    color: #fff;
    margin: 0.4rem 0;
}

footer a {
    color: #fff;
    text-decoration: underline;
}

footer a:hover {
    opacity: 0.85;
}

.footer-contact {
    word-break: break-word;
}

/* Responsive */
@media (max-width: 768px) {
    .about-content,
    .hero-content {
        flex-direction: column;
        text-align: center;
    }

    nav a {
        display: inline-block;
        margin: 0.4rem 0;
    }

    .about-photo,
    .photo {
        flex: 0 0 auto;
    }

    .about-photo img,
    .photo img {
        width: 180px;
        height: 180px;
    }

    header h1 {
        font-size: 1.6rem;
    }

    h2 {
        font-size: 1.2rem;
    }

    .container {
        width: 95%;
    }
}