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

header {
    background-color: #2c3e50;
    color: white;
    padding: 10px 0;
    text-align: center;
}
header h1 {
    margin: 0;
}
header a {
    text-decoration: none;
    color: #fffefe;
}

section.apostilas {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    padding: 20px;
}

.apostila {
    background-color: white;
    margin: 15px;
    padding: 20px;
    border: 1px solid #ddd;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    width: 300px;
    text-align: center;
}

.apostila h2 {
    font-size: 1.5em;
    margin-bottom: 20px;
}

.apostila button {
    background-color: #3498db;
    color: white;
    padding: 10px 15px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
}

.apostila button:hover {
    background-color: #2b8dce;
}