body {
    font-family: Arial, sans-serif;
    color: #333;
    background-color: #f4f4f4;
}

header {
    background-color: #1a1a1a;
    color: #fff;
    padding: 10px 0;
    text-align: center;
}

nav ul {
    list-style-type: none;
    padding: 0;
}

nav ul li {
    display: inline;
    margin: 0 10px;
}

nav ul li a {
    color: #fff;
    text-decoration: none;
}

section {
    padding: 20px;
    text-align: center;
    background-color: #fff;
    color: #333;
    margin-bottom: 20px;
}

.app-image, .feature-image {
    width: 100%;
    max-width: 600px;
    margin: 20px auto;
    display: block;
}

.feature-images {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
}

footer {
    background-color: #1a1a1a;
    color: #fff;
    text-align: center;
    padding: 10px 0;
    position: fixed;
    bottom: 0;
    width: 100%;
}