body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

header {
    background-color: #003058; 
    color: #ffffff;
    padding: 20px; 
    text-align: center; 
}

nav {
    background-color: #f4f4f4; 
}

.nav-menu {
    display: flex; 
    justify-content: center;
    list-style-type: none;
    padding: 0; 
    margin: 0; 
}

.nav-menu li {
    margin: 0 15px; 
}

.nav-menu a {
    text-decoration: none; 
    color: #003058;
    font-weight: bold; 
}

@media (max-width: 768px) {
    .nav-menu {
        flex-direction: column;
        align-items: center; 
    }

    .nav-menu li {
        margin: 10px 0; 
    }
}

.hero {
    position: relative; 
    background-image: url('gears.jpg'); 
    background-size: cover; 
    background-position: center; 
    height: 400px; 
    padding: 60px; 
    text-align: center; 
    color: white
}

.hero::before {
    content: "";
    position: absolute; 
    top: 0;
    left: 0; 
    right: 0; 
    bottom: 0; 
    background-color: rgba(0, 48, 88, 0.5); 
    z-index: 1; 
}

.hero-text {
    position: relative; 
    z-index: 2; 
}

.portfolio-section {
    margin: 20px; 
}

.portfolio-gallery {
    display: flex; 
    flex-wrap: wrap; 
    justify-content: center; 
}

.portfolio-item {
    margin: 10px; 
    flex: 1 1 200px; 
}

.portfolio-item img {
    width: 100%; 
    height: auto;
}

footer {
    background-color: #003058; 
    color: white; 
    text-align: center; 
    padding: 10px; 
}

@media (max-width: 992px) {
    .portfolio-item {
        flex: 1 1 768px; 
    }
}

@media (max-width: 768px) {
    .portfolio-item {
        flex: 1 1 100%; 
    }

    .hero {
        height: 300px; 
        padding: 40px; 
    }
}