/* --- VARIABLES CSS & RESET --- */
:root {
    --primary-blue: #007BFF;       /* Azul Eléctrico Principal */
    --accent-cyan: #00C6FF;        /* Cian para degradados */
    --dark-text: #1A1A2E;          /* Gris muy oscuro para texto */
    --light-text: #6c757d;         /* Gris suave para párrafos */
    --bg-body: #F8F9FA;            /* Blanco humo para fondo general */
    --bg-white: #FFFFFF;           /* Blanco puro para tarjetas */
    --shadow-soft: 0 10px 30px rgba(0, 123, 255, 0.08); /* Sombra azulada suave */
    --radius: 12px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--bg-body);
    color: var(--dark-text);
    line-height: 1.6;
    overflow-x: hidden;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }

/* --- HEADER --- */
header {
    background-color: var(--bg-white);
    padding: 1rem 5%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 15px rgba(0,0,0,0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-blue);
    display: flex;
    align-items: center;
    gap: 10px;
}

nav ul {
    display: flex;
    gap: 2rem;
}

nav a {
    font-weight: 500;
    transition: color 0.3s;
}

nav a:hover { color: var(--primary-blue); }

.btn-primary {
    background: linear-gradient(135deg, var(--primary-blue), var(--accent-cyan));
    color: white;
    padding: 0.7rem 1.5rem;
    border-radius: 50px;
    font-weight: 600;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 123, 255, 0.3);
}

/* --- HERO SECTION --- */
.hero {
    text-align: center;
    padding: 5rem 1rem;
    background: var(--bg-white);
    border-bottom-left-radius: 50px;
    border-bottom-right-radius: 50px;
    margin-bottom: 3rem;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: -webkit-linear-gradient(var(--primary-blue), var(--accent-cyan));
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.2rem;
    color: var(--light-text);
    max-width: 600px;
    margin: 0 auto 2rem auto;
}

/* --- TIPS GRID SECTION --- */
.tips-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
    font-size: 2rem;
    color: var(--dark-text);
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--bg-white);
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-soft);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid rgba(0, 123, 255, 0.05);
    text-align: center;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 123, 255, 0.15);
    border-color: var(--accent-cyan);
}

.icon-box {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--primary-blue);
}

.card h3 {
    margin-bottom: 0.8rem;
    font-size: 1.2rem;
}

.card p {
    font-size: 0.95rem;
    color: var(--light-text);
}

/* --- FOOTER --- */
footer {
    background-color: var(--bg-white);
    padding: 3rem 1rem 1rem 1rem;
    text-align: center;
    margin-top: 4rem;
    border-top: 1px solid #eee;
}

.footer-links {
    margin-bottom: 1.5rem;
}

.footer-links a {
    margin: 0 10px;
    color: var(--light-text);
    font-size: 0.9rem;
}

.copyright {
    color: var(--dark-text);
    font-weight: 600;
    font-size: 0.9rem;
    padding-top: 1rem;
    border-top: 1px solid #f0f0f0;
}

/* --- RESPONSIVE MEDIA QUERIES --- */
@media (max-width: 768px) {
    .hero h1 { font-size: 2rem; }
    nav ul { display: none; } /* Oculto en móvil para simplificar el ejemplo */
    .logo { font-size: 1.2rem; }
}

/* --- NUEVA SECCIÓN INTERACTIVA --- */
.interactive-section {
    max-width: 900px;
    margin: 0 auto 4rem auto;
    padding: 0 1rem;
    text-align: center;
}

.button-group {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.btn-topic {
    background: var(--bg-white);
    color: var(--primary-blue);
    border: 2px solid var(--primary-blue);
    padding: 0.8rem 2rem;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
}

.btn-topic:hover {
    background: rgba(0, 123, 255, 0.1);
    transform: translateY(-3px);
}

.btn-topic.active {
    background: var(--primary-blue);
    color: white;
    box-shadow: 0 5px 15px rgba(0, 123, 255, 0.4);
}

.content-display {
    background: var(--bg-white);
    padding: 2.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-soft);
    max-width: 700px;
    margin: 0 auto;
    border-left: 5px solid var(--accent-cyan);
    animation: fadeIn 0.5s ease-in-out;
}

.content-display h3 {
    color: var(--primary-blue);
    margin-bottom: 1rem;
    font-size: 1.4rem;
}

/* Animación suave para el cambio de texto */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}