/* Reset básico */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    font-family: Arial, sans-serif;
    background: #f7f9fc;
    color: #333;
    line-height: 1.6;
}
header {
    background: #007bff;
    color: white;
    padding: 1rem 2rem;
    text-align: center;
}
header h1 {
    font-weight: normal;
}
nav {
    background: #0056b3;
    display: flex;
    justify-content: center;
}
nav a {
    color: white;
    padding: 1rem 2rem;
    text-decoration: none;
    font-weight: bold;
    transition: background 0.3s;
}
nav a:hover {
    background: #003f7f;
}
main {
    max-width: 900px;
    margin: 2rem auto;
    padding: 0 1rem;
}
section {
    background: white;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    display: none;
}
section.active {
    display: block;
}
h2 {
    color: #007bff;
    margin-bottom: 1rem;
}
footer {
    text-align: center;
    padding: 1rem;
    font-size: 0.9rem;
    color: #777;
    border-top: 1px solid #ddd;
}
/* Responsive */
@media (max-width: 600px) {
    nav {
        flex-direction: column;
    }
    nav a {
        padding: 0.75rem 1rem;
    }
}