body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    color: #333;
}

header {
    background-color: #333;
    color: #fff;
    padding: 1em 0;
    text-align: center;
}

header .logo {
    font-size: 2em;
}

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

header nav ul li {
    display: inline;
    margin: 0 1em;
}

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

main {
    padding: 2em;
}

.home, .about, .chapters, .contact {
    margin-bottom: 2em;
}

.btn {
    display: inline-block;
    padding: 0.5em 1em;
    background-color: #333;
    color: #fff;
    text-decoration: none;
    border-radius: 5px;
}

.btn:hover {
    background-color: #555;
}

.chapter-list {
    display: flex;
    flex-wrap: wrap;
    gap: 1em;
}

.chapter-item {
    background-color: #fff;
    padding: 1em;
    border-radius: 5px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 300px;
}

footer {
    background-color: #333;
    color: #fff;
    text-align: center;
    padding: 1em 0;
    position: fixed;
    width: 100%;
    bottom: 0;
}