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

body {
    font-family: "Segoe UI", Roboto, Arial, sans-serif;
    line-height: 1.6;
    background-image: url("/public/environnementt_plateforme_renovation_energetique.jpg");
    background-size: cover;
    background-position: center top;
    background-repeat: no-repeat;
    background-attachment: fixed;
    color: #333;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.header {
    background: #0052D4;
    color: #ffffff;
    text-align: center;
    padding: 3rem 1rem;
}

.header h1 {
    font-size: 2rem;
    font-weight: 700;
}

.container {
    flex: 1;
    max-width: 900px;
    margin: 2rem auto;
    padding: 2rem;
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.08);
    animation: fadeIn 1s ease-in-out;
}

.container p {
    margin-bottom: 1.2rem;
    font-size: 1.1rem;
}

ul {
    margin: 1rem 0 1.5rem 1.5rem;
}

ul li {
    margin-bottom: 0.8rem;
}

.start-btn {
    display: block;
    width: fit-content;
    padding: 0.9rem 1.8rem;
    margin: 2rem auto;
    font-size: 1.1rem;
    font-weight: 600;
    color: #fff;
    background: linear-gradient(135deg, #28a745, #218838);
    border: none;
    border-radius: 50px;
    text-decoration: none;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    transition: all 0.3s ease;
}

.start-btn:hover {
    background: linear-gradient(135deg, #218838, #1e7e34);
    transform: translateY(-3px);
    box-shadow: 0 6px 18px rgba(0,0,0,0.2);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.logo {
    display: block;
    margin: 2rem auto 0;
    max-width: 250px;
    height: auto;
}

@media screen and (max-device-width: 768px) {
    body {
        font-size: 1.2rem;
    }

    .header h1 {
        font-size: 2.5rem;
    }

    .container p {
        font-size: 3rem;
    }

    .start-btn {
        font-size: 2.8rem;
        padding: 1rem 2rem;
    }
}