/* Couleurs de la charte TUNI2S */
:root {
    --blue: #1a365d; /* Bleu marine du logo */
    --yellow: #f5b041; /* Jaune engin */
    --orange: #e67e22; /* Orange de la flèche */
    --light: #f4f4f4;
    --white: #ffffff;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    line-height: 1.6;
    color: #333;
    scroll-behavior: smooth;
}

/* Navigation */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 5%;
    background: var(--white);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.logo img {
    height: 60px;
}

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

.nav-links li a {
    text-decoration: none;
    color: var(--blue);
    font-weight: bold;
    margin-left: 2rem;
    transition: 0.3s;
}

.btn-nav {
    background: var(--orange);
    color: white !important;
    padding: 10px 20px;
    border-radius: 5px;
}

/* Hero Section */
.hero {
    height: 80vh;
    background: linear-gradient(rgba(26, 54, 93, 0.7), rgba(26, 54, 93, 0.7)), 
                url('https://images.unsplash.com/photo-1579412623142-69022637a76f?auto=format&fit=crop&q=80&w=2000') no-repeat center center/cover;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: white;
}

.hero-content h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
}

.cta-button {
    display: inline-block;
    margin-top: 2rem;
    padding: 15px 30px;
    background: var(--yellow);
    color: var(--blue);
    text-decoration: none;
    font-weight: bold;
    border-radius: 5px;
    text-transform: uppercase;
}

/* Services / Engins */
.services {
    padding: 5rem 5%;
    background: var(--light);
}

.section-title {
    text-align: center;
    color: var(--blue);
    font-size: 2.5rem;
    margin-bottom: 3rem;
}

.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--white);
    padding: 2rem;
    border-radius: 10px;
    text-align: center;
    border-bottom: 5px solid var(--yellow);
    transition: transform 0.3s;
}

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

.card i {
    font-size: 3rem;
    color: var(--blue);
    margin-bottom: 1rem;
}

/* Formulaire */
.contact-section {
    padding: 5rem 5%;
}

.form-container {
    max-width: 800px;
    margin: 0 auto;
    background: var(--blue);
    color: white;
    padding: 3rem;
    border-radius: 15px;
}

.form-group {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

input, select, textarea {
    width: 100%;
    padding: 12px;
    margin-bottom: 1rem;
    border-radius: 5px;
    border: none;
}

.submit-btn {
    width: 100%;
    padding: 15px;
    background: var(--orange);
    color: white;
    border: none;
    font-weight: bold;
    cursor: pointer;
    font-size: 1.1rem;
}

footer {
    text-align: center;
    padding: 2rem;
    background: #222;
    color: white;
}

/* Mobile */
@media (max-width: 768px) {
    .hero-content h1 { font-size: 2rem; }
    .form-group { flex-direction: column; }
    .nav-links { display: none; } /* Simplifié pour l'exemple */
}