/* Variables & Configuration */
:root {
    --primary-dark: #0f172a; /* Bleu nuit profond */
    --primary-light: #1e293b;
    --accent-blue: #0081a7; /* Bleu lié au logo */
    --accent-cyan: #00afb9; /* Cyan du logo */
    --text-dark: #334155;
    --text-light: #f8fafc;
    --bg-main: #ffffff;
    --bg-light: #f1f5f9;
    --font-main: 'Inter', sans-serif;
}

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

body {
    font-family: var(--font-main);
    color: var(--text-dark);
    background-color: var(--bg-main);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Typographie */
h1, h2, h3, h4 {
    color: var(--primary-dark);
    line-height: 1.2;
    margin-bottom: 1rem;
}

.text-center { text-align: center; }
.text-white { color: var(--text-light) !important; }
a.text-white { color: var(--text-light); text-decoration: underline; }

/* Layout & Containers */
.container {
    width: 100%;
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section {
    padding: 5rem 0;
}

.bg-light { background-color: var(--bg-light); }
.bg-dark { background-color: var(--primary-dark); }

.section-title {
    font-size: 2.2rem;
    text-align: center;
    margin-bottom: 3rem;
}

/* Header & Nav */
.site-header {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(5px);
    z-index: 1000;
    border-bottom: 1px solid #e2e8f0;
    padding: 1rem 0;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo-img {
    height: 40px;
    width: auto;
}

.logo-text {
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--primary-dark);
    letter-spacing: 1px;
}

.main-nav {
    display: flex;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 600;
    font-size: 0.9rem;
    transition: color 0.3s;
}

.nav-link:hover {
    color: var(--accent-blue);
}

.lang-switch button {
    background: none;
    border: none;
    cursor: pointer;
    font-weight: 600;
    color: #94a3b8;
    margin-left: 0.5rem;
    font-size: 0.9rem;
}

.lang-switch button.active {
    color: var(--primary-dark);
}

/* Hero Section */
.hero {
    padding-top: 12rem;
    padding-bottom: 8rem;
    text-align: center;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
}

.hero-title {
    font-size: 3rem;
    max-width: 800px;
    margin: 0 auto 1.5rem auto;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: #475569;
    max-width: 700px;
    margin: 0 auto 2.5rem auto;
}

.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-primary {
    background-color: var(--accent-blue);
    color: var(--text-light);
}

.btn-primary:hover {
    background-color: var(--accent-cyan);
}

/* Grids & Cards */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.card {
    background: var(--bg-main);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    border: 1px solid #e2e8f0;
    transition: transform 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

/* Timeline */
.timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    padding-left: 2rem;
    border-left: 2px solid #cbd5e1;
}

.timeline-item {
    position: relative;
    margin-bottom: 2.5rem;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -2.4rem;
    top: 0;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background-color: #cbd5e1;
}

.timeline-item.active::before {
    background-color: var(--accent-blue);
}

/* Contact Grid */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
}

.contact-list {
    list-style: none;
    margin-top: 1.5rem;
}

.contact-list li {
    margin-bottom: 0.75rem;
    font-size: 1.1rem;
}

/* Footer */
.site-footer {
    background-color: #020617;
    color: #64748b;
    text-align: center;
    padding: 2rem 0;
    font-size: 0.9rem;
}

.footer-links {
    margin-top: 1rem;
}

.footer-links a {
    color: #64748b;
    text-decoration: none;
    margin: 0 1rem;
}

/* Animations & Utilities */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 768px) {
    .main-nav { display: none; /* Simplification mobile (menu hamburger requis pour un menu complet) */ }
    .hero-title { font-size: 2.2rem; }
    .grid-3 { grid-template-columns: 1fr; }
    .contact-grid { grid-template-columns: 1fr; gap: 2rem; }
}