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

body {
    font-family: Arial, sans-serif;
    background: #f5f7fa;
    color: #222;
}

header {
    background: #0b3d91;
    color: white;
    padding: 18px 7%;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 25px;
    font-weight: bold;
}

nav a {
    color: white;
    text-decoration: none;
    margin-left: 25px;
    font-weight: bold;
}

nav a:hover {
    text-decoration: underline;
}

.hero {
    min-height: 450px;
    display: flex;
    align-items: center;
    padding: 50px 8%;
    background-image: linear-gradient(
        rgba(0, 0, 0, 0.55),
        rgba(0, 0, 0, 0.55)
    ),
    url("../images/desktop.jpg");

    background-size: cover;
    background-position: center;
    color: white;
}

.hero h1 {
    font-size: 48px;
    margin-bottom: 15px;
}

.hero p {
    font-size: 20px;
    margin-bottom: 30px;
}

.btn {
    display: inline-block;
    background: #ff9800;
    color: white;
    padding: 13px 25px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
}

.products-section {
    padding: 50px 7%;
}

.products-section h2 {
    text-align: center;
    margin-bottom: 35px;
    font-size: 32px;
}

.product-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 25px;
}

.product-card {
    background: white;
    border-radius: 10px;
    overflow: hidden;
    text-align: center;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.12);
    padding-bottom: 20px;
    transition: 0.3s;
}

.product-card:hover {
    transform: translateY(-7px);
}

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

.product-card h3 {
    margin: 15px 5px 8px;
}

.product-card p {
    color: #666;
    padding: 0 10px;
}

.product-card h4 {
    color: #0b3d91;
    font-size: 22px;
    margin: 15px;
}

.product-card button,
form button {
    border: none;
    background: #0b3d91;
    color: white;
    padding: 11px 25px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
}

.product-card button:hover,
form button:hover {
    background: #06265c;
}

.page-title {
    background: #e8f0ff;
    text-align: center;
    padding: 55px 20px;
}

.page-title h1 {
    font-size: 40px;
    color: #0b3d91;
}

.about,
.contact {
    max-width: 900px;
    margin: 50px auto;
    background: white;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 3px 15px rgba(0, 0, 0, 0.1);
}

.about h2,
.contact h2 {
    color: #0b3d91;
    margin-bottom: 20px;
}

.about p {
    line-height: 1.8;
    margin-bottom: 15px;
}

.contact p {
    margin: 12px 0;
}

form {
    margin-top: 30px;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

form input,
form textarea {
    width: 100%;
    padding: 13px;
    border: 1px solid #ccc;
    border-radius: 5px;
    font-size: 15px;
}

form textarea {
    height: 130px;
    resize: vertical;
}

footer {
    background: #0b3d91;
    color: white;
    text-align: center;
    padding: 20px;
    margin-top: 40px;
}

/* Tablet */
@media (max-width: 900px) {

    header {
        flex-direction: column;
        gap: 15px;
    }

    .product-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .hero h1 {
        font-size: 38px;
    }
}

/* Mobile */
@media (max-width: 600px) {

    nav a {
        margin: 5px;
        font-size: 14px;
    }

    .product-grid {
        grid-template-columns: 1fr;
    }

    .hero {
        min-height: 350px;
    }

    .hero h1 {
        font-size: 32px;
    }

    .about,
    .contact {
        margin: 30px 15px;
        padding: 25px;
    }
}
```