/* --- Variables & Reset --- */
:root {
    --bg-color: #fcfcfc;
    --surface-color: #ffffff;
    --border-color: #e5e7eb;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --accent-color: #2563eb;
    --accent-hover: #1d4ed8;
    --radius: 8px;
    --transition: 0.2s ease;
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* --- Header --- */
.site-header {
    background-color: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    flex-wrap: wrap;
}

.logo {
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--text-primary);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.nav-btn {
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    padding: 0.45rem 0.85rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    background-color: var(--surface-color);
    transition: all var(--transition);
}

.nav-btn:hover {
    color: var(--text-primary);
    border-color: var(--text-primary);
    background-color: #f3f4f6;
}

/* --- Main / Hero --- */
.main-content {
    flex: 1;
    max-width: 900px;
    width: 100%;
    margin: 0 auto;
    padding: 4rem 1.5rem;
}

.hero {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.tagline {
    font-size: 0.9rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
}

.student-name {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
}

.bio-card {
    margin-top: 0.5rem;
    padding: 1.5rem;
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
}

.bio-card p {
    font-size: 1.1rem;
    color: var(--text-primary);
}

.bio-subtitle {
    margin-top: 0.75rem;
    font-size: 0.95rem !important;
    color: var(--text-secondary) !important;
}

/* --- Grille des cours --- */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1rem;
    margin-top: 2rem;
}

.course-card {
    padding: 1.25rem;
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    text-decoration: none;
    transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.course-card h2 {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.course-card span {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.course-card:hover {
    transform: translateY(-2px);
    border-color: var(--text-primary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.04);
}

.course-card:hover span {
    color: var(--text-primary);
}

/* --- Footer --- */
.site-footer {
    border-top: 1px solid var(--border-color);
    padding: 2rem 1.5rem;
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
    background-color: var(--surface-color);
}

/* --- Responsive adjustments --- */
@media (max-width: 640px) {
    .header-container {
        flex-direction: column;
        align-items: flex-start;
    }

    .main-content {
        padding: 2.5rem 1rem;
    }
}

/* --- Boutons d'action (Liens href) --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.55rem 1.1rem;
    font-size: 0.875rem;
    font-weight: 500;
    text-decoration: none;
    border-radius: var(--radius);
    transition: all var(--transition);
    cursor: pointer;
}

/* Bouton principal (Sombre / Noir) */
.btn-primary {
    background-color: var(--text-primary);
    color: #ffffff;
    border: 1px solid var(--text-primary);
}

.btn-primary:hover {
    background-color: #374151;
    border-color: #374151;
    color: #ffffff;
}

/* Bouton secondaire (Contour sobre) */
.btn-outline {
    background-color: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-outline:hover {
    border-color: var(--text-primary);
    background-color: #f3f4f6;
}

/* Groupe de boutons alignés */
.btn-group {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    align-items: center;
}