:root {
    --primary-color: #6c5ce7;
    --secondary-color: #00b894;
    --dark-color: #2d3436;
    --light-color: #f5f6fa;
    --text-color: #2d3436;
    --border-color: #dfe6e9;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.15);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: var(--text-color);
    background-color: var(--light-color);
    line-height: 1.6;
}

/* Navigation */
.navbar {
    background-color: white;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 28px;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s ease;
    padding: 8px 12px;
    border-radius: 4px;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
    background-color: rgba(108, 92, 231, 0.1);
}

/* Hero Section */
.hero {
    background-color: #005ea7;
    color: white;
    padding: 80px 20px;
    text-align: center;
}

.hero-content h1 {
    font-size: 48px;
    margin-bottom: 20px;
    font-weight: bold;
}

.hero-content p {
    font-size: 20px;
    opacity: 0.9;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
}

/* Sections */
.intro {
    text-align: center;
    margin-bottom: 60px;
}

.intro h2 {
    font-size: 36px;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.intro p {
    font-size: 18px;
    color: #636e72;
    max-width: 600px;
    margin: 0 auto;
}

.para {
    text-align: center;
    margin-bottom: 60px;
    border-radius: 12px;
    padding: 2rem;
    margin: 1.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    border: 2px solid #e1e4e8;
}

.para h1 {
    font-size: 30px;
    margin-bottom: 20px;
    font-weight: bold;
}

.para h2 {
    font-size: 36px;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.para p {
    font-size: 18px;
    color: #000000;
    max-width: 1000px;
    margin: 0 auto;
}

.para ul{
    font-size: 18px;
    color: #000000;
    max-width: 1000px;
    margin: 0 auto;
}

/* navigation interne aux pages (sommaire local) */
.page-nav {
    text-align: center;
    max-width: 1000px;
    margin: 20px auto 40px;
    padding: 15px 20px;
}
.page-nav ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 0;
    margin-top: 10px;
}
.page-nav a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}
.page-nav a:hover {
    text-decoration: underline;
}

/* offset pour ancre fixe */
.anchor-offset {
    display: block;
    height: 70px; /* hauteur de la navbar sticky */
    margin-top: -70px;
    visibility: hidden;
}
/* Models Grid */
.models-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.model-card {
    background: white;
    border-radius: 8px;
    padding: 30px;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: center;
}

.model-card.centered {
    max-width: 400px;
    margin: 40px auto;
}

.model-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.model-card h3 {
    font-size: 24px;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.model-card p {
    color: #636e72;
    margin-bottom: 10px;
}

.model-card .description {
    font-size: 14px;
    margin: 15px 0;
    line-height: 1.6;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 16px;
}

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

.btn-primary:hover {
    background-color: #5f4dd1;
    transform: scale(1.05);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background-color: #00a082;
}

/* Footer */
.footer {
    background-color: var(--dark-color);
    color: white;
    text-align: center;
    padding: 40px 20px;
    margin-top: 60px;
}

.footer-content p {
    margin: 10px 0;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-content h1 {
        font-size: 32px;
    }

    .hero-content p {
        font-size: 16px;
    }

    .nav-menu {
        gap: 15px;
        font-size: 14px;
    }

    .models-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .nav-container {
        flex-wrap: wrap;
    }
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.mt-4 {
    margin-top: 40px;
}

.mb-4 {
    margin-bottom: 40px;
}

.mt-2 {
    margin-top: 20px;
}

.mb-2 {
    margin-bottom: 20px;
}

.spacer {
    margin: 40px 0;
}

ul {
    list-style-type: none;
}