body {
    margin: 0;
    height: 100vh;
    background: linear-gradient(to bottom, #003366, #e0eafc);
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: #333;
}
.logo-container {
   margin-top: 0px; 
    text-align: center;
    background-color: #f2f2f2;
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
    max-width: 700px;
    margin-bottom: 20px; 
}

.header-img {
    max-width: 40%;
    height: auto;
    margin-bottom: 20px; 
}
<br>
.logo {
    max-height: 120px;
    margin-bottom: 20px;
}
nav {
    margin-top: 20px;
}
nav a {
    margin: 0 15px;
    text-decoration: none;
    color: #003366;
    font-weight: bold;
}
footer {
    margin-top: 30px;
    font-size: 12px;
    color: #666;
}