body {
    font-family: sans-serif;
    margin: 0;
    background-color: #f4f4f4;
}
.container {
    max-width: 1000px;
    padding: 1em;
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
header {
    text-align: center;
    padding-bottom: 1em;
    border-bottom: 1px solid #ddd;
}
h1 {
    color: #333;
}
.content {
    margin-top: 1em;
}
.text-content {
    margin-bottom: 2em;
}
.image-content img {
    width: 100%;
    height: auto;
    border-radius: 4px;
}
nav {
    display: flex;
    justify-content: space-between;
    margin-top: 2em;
    padding-top: 1em;
    border-top: 1px solid #ddd;
}
.nav-link {
    padding: 0.5em 1em;
    text-decoration: none;
    background-color: #007bff;
    color: white;
    border-radius: 4px;
}
.nav-link.disabled {
    background-color: #ccc;
    cursor: not-allowed;
}