/* Variables de diseño actualizadas */
:root {
    --primary-color: #2563eb; /* Azul moderno */
    --primary-hover: #1d4ed8;
    --success-color: #10b981; /* Verde acierto */
    --error-color: #ef4444;   /* Rojo fallo */
    --text-dark: #111827;
    --text-light: #6b7280;
    --bg-light: #f9fafb;
    --white: #ffffff;
    --border-color: #e5e7eb;
}

/* Reset y Básico */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; } /* Desplazamiento suave nativo */

body {
    font-family: 'Inter', sans-serif;
    color: var(--text-dark);
    background-color: var(--bg-light);
    line-height: 1.5;
}

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

/* Botones actualizados */
.btn-primary, .btn-outline {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: center;
    border: none;
}

.btn-primary {
    background-color: var(--white);
    color: var(--primary-color);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,0.1); }

.btn-outline {
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    width: 100%;
}
.btn-outline:hover { background: var(--primary-color); color: var(--white); }

/* Cabecera y Hero (Igual que antes, simplificado) */
header { background-color: var(--white); border-bottom: 1px solid var(--border-color); sticky; top: 0; z-index: 100; }
.header-container { display: flex; justify-content: space-between; align-items: center; padding: 15px 20px; }
.logo { font-size: 1.4rem; font-weight: 800; text-decoration: none; color: var(--text-dark); }
.logo span { color: var(--primary-color); }
.nav-links { list-style: none; display: flex; gap: 15px; }
.nav-links a { text-decoration: none; color: var(--text-light); font-weight: 500; font-size: 0.9rem; }
.nav-links a:hover { color: var(--primary-color); }

.hero { background: linear-gradient(135deg, #1e40af, #2563eb); color: var(--white); text-align: center; padding: 60px 20px; }
.hero h1 { font-size: 2.2rem; font-weight: 800; margin-bottom: 15px; }
.hero p { font-size: 1.1rem; margin-bottom: 25px; opacity: 0.9; }

/* --- ESTILOS NUEVOS: PREGUNTA DEL DÍA --- */
.daily-challenge { margin-top: -30px; margin-bottom: 40px; position: relative; z-index: 10; }

.challenge-card {
    background: var(--white);
    padding: 30px;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.05);
    border: 1px solid var(--border-color);
}

.challenge-header { text-align: center; margin-bottom: 25px; }

.badge {
    background-color: #dbeafe;
    color: var(--primary-color);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.challenge-header h2 { font-size: 1.8rem; margin: 10px 0 5px; }
.challenge-header .date { color: var(--text-light); font-size: 0.9rem; }

.question-text { font-size: 1.1rem; font-weight: 600; margin-bottom: 20px; color: var(--text-dark); }

.options { display: flex; flex-direction: column; gap: 12px; }

.option-btn {
    background-color: var(--white);
    border: 2px solid var(--border-color);
    padding: 15px;
    border-radius: 10px;
    text-align: left;
    font-family: inherit;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    width: 100%;
}

.option-btn:hover:not(:disabled) { border-color: var(--primary-color); background-color: #f0f9ff; }

/* Clases para JS (Acierto/Fallo) */
.option-btn.correct { background-color: #ecfdf5; border-color: var(--success-color); color: #065f46; font-weight: 600; }
.option-btn.incorrect { background-color: #fef2f2; border-color: var(--error-color); color: #991b1b; opacity: 0.7; }

.feedback { margin-top: 20px; padding: 15px; border-radius: 8px; font-weight: 600; text-align: center; }
.feedback.correct-bg { background-color: var(--success-color); color: var(--white); }
.feedback.incorrect-bg { background-color: #fee2e2; color: #991b1b; border: 1px solid #fecaca;}

.hidden { display: none; }

/* --- ESTILOS ACTUALIZADOS: CATEGORÍAS --- */
.section-title { text-align: center; margin: 40px 0; font-size: 1.8rem; font-weight: 700; }
.grid-categorias { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 25px; margin-bottom: 50px; }

.card {
    background: var(--white);
    padding: 30px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    display: flex; flex-direction: column; align-items: center; text-align: center; /* Centrar contenido */
}
.card:hover { transform: translateY(-3px); box-shadow: 0 5px 15px rgba(0,0,0,0.05); }

/* Estilo para las imágenes/iconos pequeños */
.card-icon {
    width: 60px; height: 60px;
    margin-bottom: 20px;
    object-fit: contain; /* Asegura que no se deforme */
}

.card h3 { font-size: 1.3rem; margin-bottom: 10px; color: var(--text-dark); }
.card p { color: var(--text-light); margin-bottom: 20px; font-size: 0.95rem; flex-grow: 1; /* Empuja el botón abajo */ }

/* Anuncios y Footer (Simplificado) */
.ad-container { margin: 30px auto; text-align: center; }
.ad-slot { background-color: #f3f4f6; border: 1px dashed #d1d5db; padding: 15px; border-radius: 8px; }
footer { background-color: var(--text-dark); color: var(--white); text-align: center; padding: 30px 20px; }

/* Responsive */
@media (max-width: 768px) {
    .hero h1 { font-size: 1.8rem; }
    .challenge-card { padding: 20px; }
    .challenge-header h2 { font-size: 1.5rem; }
}