/* --- 1. CONFIGURACIÓN GENERAL Y VARIABLES --- */
:root {
    --bg-color: #f8f9fa;
    --font-color: #343a40;
    --primary-color: #4a69bd;
    --card-bg: #ffffff;
    --shadow: 0 4px 6px rgba(0,0,0,0.05);
    --shadow-hover: 0 10px 20px rgba(0,0,0,0.1);
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--font-color);
    margin: 0;
    line-height: 1.6;
}

/* --- 2. LAYOUT PRINCIPAL Y NAVEGACIÓN --- */
.main-header {
    background: var(--card-bg);
    box-shadow: var(--shadow);
    padding: 0 5%;
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 2rem;
    margin: 0;
    padding: 0;
}

.nav-links a {
    text-decoration: none;
    color: var(--font-color);
    font-weight: 600;
    padding: 0.5rem 0;
    position: relative;
    transition: color 0.3s ease;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--primary-color);
    transform: scaleX(0);
    transform-origin: right;
    transition: transform 0.4s ease-out;
}

.nav-links a:hover, .nav-links a.active {
    color: var(--primary-color);
}
.nav-links a:hover::after, .nav-links a.active::after {
    transform: scaleX(1);
    transform-origin: left;
}


/* --- 3. SECCIÓN HERO Y CONTENIDO --- */
.content-wrapper {
    max-width: 1100px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

.hero-section {
    text-align: center;
    margin-bottom: 4rem;
}

.hero-section h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-section p {
    font-size: 1.1rem;
    color: #6c757d;
    max-width: 650px;
    margin: 0 auto;
}

/* --- 4. CUADRÍCULA DE CARACTERÍSTICAS (SPRITES) --- */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.feature-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    border: 1px solid #e9ecef;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-hover);
    cursor: default;
}

.feature-card h3 {
    margin: 1.5rem 0 0.5rem;
    font-size: 1.25rem;
}

.feature-card p {
    color: #6c757d;
    margin: 0;
}


/* --- 5. LÓGICA DEL SPRITE CSS (TUS MEDIDAS EXACTAS) --- */
.icon {
    display: inline-block;
    width: 80.7px;  /* Ancho exacto del sprite */
    height: 80.7px; /* Alto exacto del sprite */
    background: url(sprite-icons.png) no-repeat;
    transform: scale(0.9); /* Un poco más pequeño para dar espacio */
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.feature-card:hover .icon {
    transform: scale(1.1); /* Crece al pasar el cursor por la tarjeta */
}

/* Posiciones de fondo según la cuadrícula proporcionada */
/* Fila 1 */
.icon-1 { background-position: 0px 0px; }            /* Twitter */
.icon-2 { background-position: -80.7px 0px; }         /* RSS */
.icon-3 { background-position: -161.3px 0px; }        /* Facebook */

/* Fila 2 */
.icon-4 { background-position: 0px -80.7px; }         /* Star Yellow */
.icon-5 { background-position: -80.7px -80.7px; }     /* Star Gray */
.icon-6 { background-position: -161.3px -80.7px; }    /* Arrow Down */

/* Fila 3 */
.icon-7 { background-position: 0px -161.3px; }        /* Arrow Up */
.icon-8 { background-position: -80.7px -161.3px; }    /* Arrow Right */
.icon-9 { background-position: -161.3px -161.3px; }   /* Arrow Left */


/* --- 6. FOOTER --- */
.main-footer {
    text-align: center;
    padding: 2rem;
    margin-top: 2rem;
    color: #6c757d;
    font-size: 0.9rem;
    border-top: 1px solid #e9ecef;
}