body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background-color: #f4f6f8;
    color: #333;
}

header {
    background-color: #1e3a8a;
    color: white;
    text-align: center;
    padding: 30px 20px;
}

main {
    max-width: 900px;
    margin: 30px auto;
    padding: 0 20px;
}

.content-box {
    background-color: white;
    padding: 25px;
    border-left: 6px solid #1e3a8a;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    animation: pageTurn 0.7s ease;
}

.content-box h2 {
    margin-top: 0;
    color: #1e3a8a;
}

.intro {
    font-size: 16px;
    margin-bottom: 15px;
}

ul {
    padding-left: 20px;
}

.controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 20px;
}

.controls button {
    padding: 10px 18px;
    background-color: #1e3a8a;
    color: white;
    border: none;
    cursor: pointer;
    border-radius: 5px;
}

.controls button:hover {
    background-color: #162f6b;
}

#pageNumber {
    font-weight: bold;
}

footer {
    text-align: center;
    padding: 15px;
    background-color: #e5e7eb;
    margin-top: 40px;
}

/* Animación */
@keyframes pageTurn {
    from {
        opacity: 0;
        transform: translateX(20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}