body {
    font-family: 'Segoe UI', sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f2f4f8;
    color: #333;
    line-height: 1.6;
    scroll-behavior: smooth;
}
.main-header {
    background-color: #0077cc;
    color: #fff;
    text-align: center;
    padding: 40px 20px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.main-header h1 {
    margin: 0;
    font-size: 2.2rem;
}

.main-nav {
    background-color: #005fa3;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.main-nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}

.main-nav li {
    margin: 0;
}

.main-nav a {
    display: block;
    padding: 15px 25px;
    color: #fff;
    text-decoration: none;
    font-weight: 500;
    transition: background-color 0.3s ease;
}

.main-nav a:hover,
.main-nav a.active {
    background-color: #004d80;
}

.content {
    max-width: 1000px;
    margin: 40px auto;
    padding: 30px;
    background-color: #fff;
    border-radius: 14px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.06);
}

section {
    margin-bottom: 60px;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 1s ease forwards;
}

section:nth-child(1) { animation-delay: 0.2s; }
section:nth-child(2) { animation-delay: 0.4s; }
section:nth-child(3) { animation-delay: 0.6s; }
section:nth-child(4) { animation-delay: 0.8s; }
section:nth-child(5) { animation-delay: 1s; }

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.content h2 {
    color: #0077cc;
    margin-top: 0;
    font-size: 1.8rem;
}

.content p, .content ul {
    margin-bottom: 1.2em;
    font-size: 1.05rem;
}

.content img {
    width: 100%;
    border-radius: 10px;
    margin-top: 20px;
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.1);
}

.main-footer {
    background-color: #0077cc;
    color: #fff;
    text-align: center;
    padding: 20px;
    font-size: 0.95rem;
    margin-top: 40px;
}

#volver-arriba {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background-color: #0077cc;
    color: white;
    padding: 12px 16px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    font-size: 18px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    transition: background-color 0.3s ease;
    display: none;
}

#volver-arriba:hover {
    background-color: #005fa3;
}

@media screen and (max-width: 768px) {
    .main-nav ul {
        flex-direction: column;
        align-items: center;
    }

    .main-nav a {
        padding: 12px 20px;
        width: 100%;
        text-align: center;
    }

    .content {
        margin: 20px;
        padding: 20px;
    }

    .main-header h1 {
        font-size: 1.8rem;
    }

    .content h2 {
        font-size: 1.5rem;
    }
}