:root {
    /* Palette Moderne & Data */
    --primary: #2563eb;
    --primary-dark: #1e40af;
    --secondary: #10b981;
    --accent: #f59e0b;
    --dark: #0f172a;
    --slate-800: #1e293b;
    --slate-100: #f1f5f9;
    --light: #ffffff;
    --text-main: #334155;
    --text-muted: #64748b;
    
    /* Système d'espacement (Spacing) */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 2rem;
    --space-lg: 4rem;
    --space-xl: 8rem;
    
    /* Bordures & Ombres */
    --radius: 12px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12);
    --shadow-md: 0 10px 15px -3px rgba(0,0,0,0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Poppins', sans-serif;
    line-height: 1.7; /* Meilleure lisibilité */
    color: var(--text-main);
    background-color: var(--light);
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-md);
}

/* --- NAVIGATION --- */
header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px); /* Effet flou moderne */
    padding: 1.2rem 0;
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    color: var(--dark);
}

.logo span {
    color: var(--primary);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2.5rem;
    align-items: center;
}

.nav-links a:not(.btn-secondary) {
    text-decoration: none;
    color: var(--text-main);
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
}

.nav-links a:hover {
    color: var(--primary);
}

/* --- HERO SECTION --- */
.hero {
    padding: var(--space-xl) 0;
    background: radial-gradient(circle at top right, #f8fafc, #e2e8f0);
    text-align: center;
    overflow: hidden;
}

.hero h1 {
    font-size: clamp(2.5rem, 5vw, 4rem); /* Taille adaptative */
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: var(--space-md);
    color: var(--dark);
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-muted);
    max-width: 800px;
    margin: 0 auto var(--space-lg);
}

.hero-btns {
    display: flex;
    gap: var(--space-sm);
    justify-content: center;
}

/* --- BUTTONS --- */
.btn-primary, .btn-secondary, .btn-outline {
    padding: 1rem 2.2rem;
    border-radius: var(--radius);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    display: inline-block;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.39);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.btn-secondary {
    background: var(--secondary);
    color: white;
    padding: 0.6rem 1.5rem;
}

.btn-outline {
    border: 2px solid var(--primary);
    color: var(--primary);
    background: transparent;
}

.btn-outline:hover {
    background: var(--primary);
    color: white;
}

/* --- FEATURES / PROGRAMME --- */
.features {
    padding: var(--space-xl) 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: var(--space-lg);
    font-weight: 700;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--space-md);
}

.card {
    background: white;
    padding: var(--space-lg);
    border-radius: var(--radius);
    border: 1px solid var(--slate-100);
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary);
}

.card i {
    font-size: 3rem;
    background: linear-gradient(45deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: var(--space-md);
}

.card h3 {
    margin-bottom: var(--space-sm);
    font-size: 1.4rem;
}

/* --- STATS SECTION --- */
.stats {
    padding: var(--space-xl) 0;
}

.grid-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-md);
    padding: var(--space-lg);
    background: var(--dark);
    border-radius: 24px;
    color: white;
}

.stat-item h4 {
    font-size: 2.5rem;
    color: var(--secondary);
    margin-bottom: var(--space-xs);
}

.stat-item p {
    color: var(--text-muted);
    font-weight: 300;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-size: 0.85rem;
}

/* --- FOOTER --- */
footer {
    padding: var(--space-xl) 0 var(--space-md);
    background: var(--slate-100);
    text-align: center;
}

footer h2 {
    font-size: 2.2rem;
    margin-bottom: var(--space-sm);
}

footer .social-links {
    margin: var(--space-md) 0;
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}

.social-links a {
    font-size: 1.5rem;
    color: var(--dark);
    transition: var(--transition);
}

.social-links a:hover {
    color: var(--primary);
    transform: scale(1.2);
}

.copy {
    margin-top: var(--space-lg);
    padding-top: var(--space-md);
    border-top: 1px solid #cbd5e1;
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* --- RESPONSIVE --- */
@media (max-width: 768px) {
    :root {
        --space-xl: 4rem; /* Moins d'espace sur mobile */
    }
    
    .nav-links { display: none; } /* On pourrait ajouter un menu burger ici */
    
    .hero-btns {
        flex-direction: column;
        padding: 0 var(--space-md);
    }
    
    .btn-outline { margin-left: 0; }
    
    .grid-stats {
        gap: var(--space-lg);
    }
}