/* Variables de color mejoradas con una paleta más armónica */
:root {
    --primary-dark: #2c3e50;     /* Azul oscuro principal */
    --primary-light: #3498db;    /* Azul claro */
    --accent: #e74c3c;           /* Rojo coral para destacar */
    --accent-light: #ff7f50;     /* Coral más claro para hover */
    --background: #f8f9fa;       /* Fondo claro suave */
    --text-dark: #2d3436;        /* Texto oscuro */
    --text-light: #f5f6fa;       /* Texto claro */
    --success: #27ae60;          /* Verde */
    --warning: #f39c12;          /* Amarillo/naranja */
    --info: #2980b9;             /* Azul información */
    --card-bg: #ffffff;          /* Fondo de tarjetas */
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.12);
    --transition: all 0.3s ease;
    --border-radius: 12px;       /* Radio de borde consistente */
}

/* Estilos generales con fondo degradado sutil */
body {
    font-family: 'Open Sans', sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e8eb 100%);
    color: var(--text-dark);
    line-height: 1.7;
    margin: 0;
    padding: 0;
    min-height: 100vh;
}

/* Mejoras para títulos con tipografía jerárquica */
h1, h2, h3, h4, h5, h6 {
    font-family: 'Merriweather', serif;
    color: var(--primary-dark);
    font-weight: 700;
    margin-bottom: 1rem;
}

.site-title {
    font-size: 2.8rem;
    margin-bottom: 0.5rem;
    color: white;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
    position: relative;
    display: inline-block;
    padding-bottom: 0.5rem;
}

.site-title::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80%;
    height: 3px;
    background: rgba(255, 255, 255, 0.7);
    border-radius: 3px;
}

.site-description {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.9);
    font-weight: 300;
    margin-top: 0;
}

h2 {
    font-size: 2.2rem;
    color: var(--primary-dark);
    position: relative;
    padding-bottom: 0.5rem;
    margin-top: 2.5rem;
}

h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 4px;
    background: var(--accent);
    border-radius: 2px;
}

h3 {
    font-size: 1.8rem;
    color: var(--primary-dark);
    margin-top: 1.8rem;
    position: relative;
    padding-left: 1.2rem;
}

h3::before {
    content: "»";
    position: absolute;
    left: 0;
    color: var(--accent);
}

/* Encabezado mejorado con degradado y efecto de partículas */
.main-header {
    background: linear-gradient(135deg, var(--primary-dark) 0%, #1a5276 100%);
    color: var(--text-light);
    padding: 4rem 0;
    text-align: center;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    position: relative;
    overflow: hidden;
}

.main-header::before {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    animation: particleAnimation 15s linear infinite;
}

@keyframes particleAnimation {
    0% { transform: translate(0, 0); }
    100% { transform: translate(50%, 50%); }
}

/* Navegación mejorada con efecto de subrayado animado */
.main-nav {
    background-color: var(--primary-dark);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.1);
}

.main-nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 1.5rem;
}

.main-nav li {
    margin: 0;
}

.main-nav a {
    color: var(--text-light);
    font-weight: 600;
    padding: 0.7rem 1.5rem;
    border-radius: 50px;
    transition: var(--transition);
    position: relative;
    text-decoration: none;
    display: inline-block;
}

.main-nav a::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: var(--transition);
}

.main-nav a:hover {
    color: white;
}

.main-nav a:hover::after {
    width: 70%;
}

/* Contenedor principal con animación de entrada */
.main-content {
    padding: 3rem 0;
    animation: fadeIn 0.6s ease-out;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Sección de presentación del equipo */
.presentation-section {
    margin-bottom: 3rem;
}

.team-members {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.member-card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    text-align: center;
    border-top: 4px solid var(--primary-light);
}

.member-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
    border-top-color: var(--accent);
}

.member-card img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    margin: 0 auto 1rem;
    border: 4px solid var(--primary-light);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

.member-card h3 {
    color: var(--primary-dark);
    margin: 1rem 0 0.5rem;
}

.member-card p {
    color: #666;
    font-size: 0.95rem;
}

/* Sección de temas */
.topics-section {
    margin-bottom: 3rem;
}

.topic-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.topic-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
    text-decoration: none;
    color: var(--primary-dark);
    font-weight: 600;
    text-align: center;
    border-left: 5px solid var(--primary-light);
}

.topic-btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
    border-left-color: var(--accent);
    color: var(--accent);
}

/* Tarjetas de ejemplos y ejercicios */
.examples-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.example-card, .exercise-card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-left: 5px solid var(--primary-light);
}

.example-card:hover, .exercise-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
    border-left-color: var(--accent);
}

.example-content {
    margin-top: 1rem;
    line-height: 1.6;
}

/* Sección de videos */
.video-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.video-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-left: 5px solid var(--info);
}

.video-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
    border-left-color: var(--accent);
}

/* Fórmulas matemáticas destacadas */
.formula {
    background-color: #f8f9fa;
    border-left: 4px solid var(--accent);
    padding: 1rem 1.5rem;
    font-family: 'Courier New', monospace;
    margin: 1.5rem 0;
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
    color: var(--primary-dark);
    font-weight: bold;
    font-size: 1.1rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
    display: inline-block;
}

/* Botones mejorados con íconos */
.video-link, .solve-btn, .action-btn, .topic-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.8rem 1.8rem;
    border-radius: 50px;
    font-weight: 600;
    transition: var(--transition);
    text-decoration: none;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.1);
    gap: 0.7rem;
}

.video-link {
    background: var(--accent);
    color: white;
}

.video-link::before {
    content: "▶";
    font-size: 0.9rem;
}

.solve-btn {
    background: var(--success);
    color: white;
}

.solve-btn::before {
    content: "✍";
}

.action-btn {
    background: var(--primary-light);
    color: white;
}

.video-link:hover {
    background: var(--accent-light);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(231, 76, 60, 0.3);
}

.solve-btn:hover {
    background: #219653;
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(39, 174, 96, 0.3);
}

.action-btn:hover {
    background: #2980b9;
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.3);
}

/* Pie de página */
.main-footer {
    background: var(--primary-dark);
    color: var(--text-light);
    padding: 2rem 0;
    text-align: center;
    margin-top: 3rem;
}

.main-footer p {
    margin: 0;
    font-size: 0.95rem;
    opacity: 0.8;
}

/* Animaciones */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.topic-content, .examples-section, .videos-section {
    animation: fadeIn 0.6s ease-out forwards;
}

.examples-section {
    animation-delay: 0.1s;
}

.videos-section {
    animation-delay: 0.2s;
}

/* Responsive design */
@media (max-width: 768px) {
    .container {
        padding: 0 1.5rem;
    }
    
    .site-title {
        font-size: 2.2rem;
    }
    
    h2 {
        font-size: 1.8rem;
    }
    
    h3 {
        font-size: 1.5rem;
    }
    
    .main-nav ul {
        flex-wrap: wrap;
        gap: 0.5rem;
    }
    
    .main-nav a {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }
    
    .team-members, .topic-buttons, .examples-grid, .video-links {
        grid-template-columns: 1fr;
    }
    
    .example-card, .exercise-card {
        padding: 1.5rem;
    }
}

/* Efecto de carga para contenido dinámico */
.loading {
    position: relative;
    overflow: hidden;
}

.loading::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.6), transparent);
    animation: loadingAnimation 1.5s infinite;
}

@keyframes loadingAnimation {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}