:root {
    --bg-dark: #0b1335;       /* Bleu nuit profond */
    --accent-purple: #8787c8; /* Violet/pervanche */
    --light-bg: #f4f6fa;
    --dark-text: #2d3748;
    --white: #ffffff;
    --card-shadow: 0 8px 20px rgba(11, 19, 53, 0.06);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Roboto', sans-serif;
}

html {
    scroll-behavior: smooth;
}

body {
    color: var(--dark-text);
    background-color: #eef2f7;
    line-height: 1.6;
}

/* Header Sticky */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: var(--bg-dark);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.15);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 20px;
    position: relative;
}

.logo-container .logo {
    max-height: 100px; /* Logo agrandi */
    width: auto;
    display: block;
    transition: max-height 0.3s ease;
}

/* Navigation PC - Forcée en affichage permanent */
nav {
    display: block !important;
}

nav ul {
    list-style: none;
    display: flex;
    align-items: center;
    gap: 15px;
}

nav ul li a {
    color: var(--white);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    text-transform: uppercase;
    padding: 8px 14px;
    border-radius: 6px;
    transition: all 0.3s ease;
    display: inline-block;
}

nav ul li a:hover {
    color: var(--accent-purple);
    background-color: rgba(255, 255, 255, 0.05);
}

nav ul li a.btn-nav {
    background-color: var(--accent-purple);
    color: var(--bg-dark) !important;
    font-weight: 700;
}

nav ul li a.btn-nav:hover {
    background-color: var(--white);
    color: var(--bg-dark) !important;
}

/* Bouton Burger Mobile */
.mobile-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 22px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
}

.mobile-toggle span {
    height: 3px;
    width: 100%;
    background-color: var(--white);
    border-radius: 3px;
}

/* Hero Banner */
.hero-banner {
    background: linear-gradient(135deg, #0b1335 0%, #1a275c 100%);
    color: var(--white);
    text-align: center;
    padding: 90px 20px;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.hero-content h1 {
    font-size: 3.5rem;
    font-weight: 700;
    letter-spacing: 3px;
    margin-bottom: 5px;
}

.hero-content h2 {
    font-size: 1.6rem;
    color: var(--accent-purple);
    margin-bottom: 20px;
    font-weight: 400;
}

.hero-content p {
    font-size: 1.15rem;
    margin-bottom: 30px;
    opacity: 0.9;
}

.btn-primary {
    display: inline-block;
    background-color: var(--accent-purple);
    color: var(--bg-dark);
    padding: 14px 28px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: 700;
    text-transform: uppercase;
    box-shadow: 0 4px 15px rgba(135, 135, 200, 0.3);
    transition: transform 0.2s, background-color 0.2s;
}

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

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

.card-section {
    background: var(--white);
    padding: 40px;
    margin-bottom: 35px;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
    scroll-margin-top: 120px;
}

.section-header {
    margin-bottom: 25px;
}

.section-header h1 {
    font-size: 2rem;
    color: var(--bg-dark);
    margin-bottom: 8px;
}

.underline {
    width: 60px;
    height: 4px;
    background-color: var(--accent-purple);
    border-radius: 2px;
}

/* Cards & Grids */
.grid-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.grid-item {
    background-color: var(--light-bg);
    padding: 22px;
    border-radius: 8px;
    border-left: 4px solid var(--accent-purple);
    transition: transform 0.2s;
}

.grid-item:hover {
    transform: translateY(-3px);
}

.grid-item h2 {
    font-size: 1.2rem;
    color: var(--bg-dark);
    margin-bottom: 10px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.feature-card {
    background: var(--light-bg);
    padding: 25px;
    border-radius: 8px;
    text-align: center;
}

.feature-card h3 {
    color: var(--bg-dark);
    font-size: 1.2rem;
    margin-bottom: 10px;
}

/* Contact Grid & Legal */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.contact-card {
    background: var(--light-bg);
    padding: 30px 20px;
    text-align: center;
    border-radius: 8px;
    border-bottom: 4px solid var(--accent-purple);
}

.contact-card .icon {
    font-size: 2rem;
    margin-bottom: 10px;
}

.contact-card h3 {
    color: var(--bg-dark);
    margin-bottom: 8px;
}

.contact-card a {
    color: var(--bg-dark);
    font-weight: 700;
    text-decoration: none;
}

.legales-box {
    background-color: #f1f3f9;
    padding: 20px;
    border-radius: 8px;
    text-align: center;
    font-size: 0.95rem;
    color: #555;
    border: 1px solid #e2e8f0;
}

.legales-box h3 {
    color: var(--bg-dark);
    margin-bottom: 10px;
}

/* Footer */
footer {
    background-color: var(--bg-dark);
    color: var(--white);
    text-align: center;
    padding: 25px;
}

#backToTopBtn {
    display: none;
    position: fixed;
    bottom: 25px;
    right: 25px;
    z-index: 999;
    background-color: var(--accent-purple);
    color: var(--bg-dark);
    border: none;
    width: 45px;
    height: 45px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 18px;
    font-weight: bold;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

/* Responsive Mobile & Tablette */
@media (max-width: 900px) {
    .logo-container .logo {
        max-height: 75px;
    }

    .mobile-toggle {
        display: flex;
    }

    nav {
        display: none !important;
        width: 100%;
        position: absolute;
        top: 100%;
        left: 0;
        background-color: var(--bg-dark);
        padding: 20px;
        box-shadow: 0 10px 15px rgba(0,0,0,0.2);
    }

    nav.active {
        display: block !important;
    }

    nav ul {
        flex-direction: column;
        gap: 10px;
    }

    nav ul li {
        width: 100%;
    }

    nav ul li a {
        display: block;
        text-align: center;
        width: 100%;
    }

    .hero-content h1 {
        font-size: 2.3rem;
    }
}