body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #eef4f9;
    color: #2c3e50;
    margin: 0;
    padding: 0;
    line-height: 1.6;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    padding: 30px 0;
    border-bottom: 2px solid #ddd;
}

header h1 {
    color: #2980b9;
    font-size: 2.8em;
    margin-bottom: 10px;
}

.subtitle {
    color: #7f8c8d;
    font-size: 1.2em;
}

.btn {
    text-decoration: none;
    color: #ffffff;
    background-color: #2980b9;
    padding: 10px 20px;
    border-radius: 8px;
    transition: background-color 0.3s ease;
    display: inline-block;
    margin-top: 10px;
}

.btn:hover {
    background-color: #1f6391;
}

.btn-primary {
    background-color: #27ae60;
}

.btn-primary:hover {
    background-color: #1e8449;
}

.intro, .donation, .contact {
    text-align: center;
    margin: 40px 0;
}

.ebooks {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: space-between;
}

.ebook {
    flex: 1 1 calc(50% - 20px);
    background-color: #ffffff;
    padding: 15px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    border-radius: 8px;
    text-align: center;
}

.ebook img {
    max-width: 350px !important; /* Tamaño máximo visual garantizado */
    width: 100% !important;
    height: auto !important;
    display: block !important;
    margin: 0 auto 15px auto !important;
    border-radius: 8px;
}

.ebook h2 {
    color: #34495e;
    margin-top: 10px;
    font-size: 1.4em;
}

footer {
    text-align: center;
    border-top: 1px solid #ddd;
    padding: 15px 0;
    color: #95a5a6;
    margin-top: 40px;
}