:root {
    --primary-blue: #002D5B;    /* Bleu profond (Sérieux) */
    --accent-orange: #FF8C00;   /* Orange/Jaune (Action/BTP) */
    --dark-grey: #2b2b2b;       /* Anthracite (Solidité) */
    --light-grey: #f4f4f4;      /* Fond de section */
    --white: #ffffff;
}

/* Mise à jour générale pour le Responsive (VI) */
body { 
    font-family: 'Montserrat', sans-serif; 
    margin: 0; 
    padding: 0; 
    color: var(--dark-grey); 
    background-color: var(--white);
    overflow-x: hidden;
}

/* Header & Nav - Sticky pour la navigation facile */
header { 
    background: var(--primary-blue); 
    color: var(--white); 
    padding: 15px 5%; 
    display: flex; 
    justify-content: space-between; 
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

header nav a {
    color: var(--white);
    text-decoration: none;
    margin-left: 20px;
    font-weight: 500;
    transition: 0.3s;
}

header nav a:hover { color: var(--accent-orange); }

.logo { font-weight: bold; font-size: 1.5rem; color: var(--accent-orange); }

/* Hero Section dynamique (5.1) */
.hero {
    background: linear-gradient(rgba(0, 45, 91, 0.8), rgba(0, 0, 0, 0.7)), url('../img/chantier.jpg');
    background-size: cover;
    background-position: center;
    height: 500px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    color: var(--white);
    padding: 0 10%;
}

.hero h1 { font-size: 3.5rem; border-left: 8px solid var(--accent-orange); padding-left: 25px; margin-bottom: 10px; }
.hero p { font-size: 1.2rem; max-width: 600px; margin-bottom: 25px; }

/* Stats Bar (5.1 - Chiffres clés) */
.stats-bar {
    background: var(--dark-grey);
    color: var(--white);
    padding: 40px 10%;
    display: flex;
    justify-content: space-around;
    text-align: center;
}

.stat-item h2 { color: var(--accent-orange); font-size: 2.5rem; margin: 0; }

/* Contact Bar (Bloc Orange sous le Hero) */
.contact-info-bar {
    background: var(--accent-orange);
    color: var(--primary-blue);
    display: flex;
    justify-content: space-around;
    padding: 25px;
    margin: 0 10%;
    position: relative;
    top: -40px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    z-index: 10;
}

/* Galerie Réalisations (5.3) */
.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    padding: 20px 0;
}

.gallery-item {
    background: var(--white);
    border-radius: 4px;
    overflow: hidden;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

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

.gallery-item img { width: 100%; height: 200px; object-fit: cover; }

/* Section Formulaire & Cards (5.5) */
.main-content { padding: 60px 10%; background: var(--light-grey); }

.form-card {
    background: var(--white);
    padding: 40px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    box-shadow: 0 0 20px rgba(0,0,0,0.05);
}

.form-group { display: flex; flex-direction: column; margin-bottom: 15px; }
.form-group label { font-weight: bold; margin-bottom: 8px; font-size: 0.9rem; }
.form-group input, .form-group select, .form-group textarea {
    padding: 12px; border: 1px solid #ddd; border-radius: 2px; background: #fafafa;
}

.btn-submit {
    background: var(--primary-blue);
    color: var(--white);
    padding: 15px 40px;
    border: none;
    font-weight: bold;
    text-transform: uppercase;
    cursor: pointer;
    transition: 0.3s;
    grid-column: span 2;
    text-align: center;
    text-decoration: none;
}

.btn-submit:hover { background: var(--accent-orange); color: var(--primary-blue); }

/* --- RESPONSIVE DESIGN (VI) --- */
@media (max-width: 768px) {
    header { flex-direction: column; text-align: center; }
    header nav { margin-top: 15px; }
    header nav a { margin: 0 10px; font-size: 0.9rem; }
    
    .hero h1 { font-size: 2.2rem; }
    
    .contact-info-bar { flex-direction: column; gap: 15px; text-align: center; top: 0; margin-bottom: 20px; }
    
    .form-card { grid-template-columns: 1fr; }
    .btn-submit { grid-column: span 1; }
    
    .stats-bar { flex-direction: column; gap: 30px; }
}
/* Classes d'animation */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease-out;
}
.reveal-visible {
    opacity: 1;
    transform: translateY(0);
}
/* Style pour le message d'erreur login */
.alert-error {
    background: #f8d7da;
    color: #721c24;
    padding: 10px;
    border-radius: 4px;
    margin-bottom: 15px;
    text-align: center;
}
/* --- Système d'Animations (Point III.2.2) --- */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease-out;
}

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

/* Effet de zoom au survol des cartes */
.card, .gallery-item {
    transition: transform 0.3s ease;
}

.card:hover, .gallery-item:hover {
    transform: translateY(-10px);
}

/* Style des messages d'alerte */
.alert-info {
    background: #d1ecf1;
    color: #0c5460;
    padding: 15px;
    border-radius: 5px;
    margin-bottom: 20px;
    border-left: 5px solid #bee5eb;
    text-align: center;
}