body {
    font-family: Arial, sans-serif;
    background-color: #f5f5f5;
    color: #333;
    margin: 0;
    padding: 0;
}

header {
    background-color: #4CAF50;
    color: white;
    padding: 1rem;
    text-align: center;
}

h1, h2 {
    color: #333;
}

nav a {
    margin: 0 1rem;
    color: white;
    text-decoration: none;
}

main {
    padding: 2rem;
    max-width: 600px;
    margin: 0 auto;
}

form {
    display: flex;
    flex-direction: column;
}

label {
    margin: 0.5rem 0 0.2rem;
}

input, button {
    padding: 0.5rem;
    margin-bottom: 1rem;
    border: 1px solid #ccc;
    border-radius: 4px;
}

button {
    background-color: #4CAF50;
    color: white;
    cursor: pointer;
}

button:hover {
    background-color: #45a049;
}

#listaLibros div {
    background-color: #e0e0e0;
    padding: 1rem;
    margin: 1rem 0;
    border-radius: 4px;
}

#TodasFrases{
    color: black;
    font-size: 2em;
    transition-duration: 2s;
}

#frase{
    transition-duration: 2s;
}

@keyframes desvanecer {
    0% {
        opacity: 1;
        color: black;
    }
    50% {
        opacity: 0.5;
    }
    100% {
        opacity: 1;
        color: white;
    }
}