/* =========================================
   1. RESET BASICO Y TIPOGRAFIA
   ========================================= */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f4f4f9;
    color: #333333;
    line-height: 1.6;
    transition: background-color 0.4s, color 0.4s; 
}

/* =========================================
   2. ENCABEZADO Y NAVEGACION
   ========================================= */
header {
    background-color: #0056b3; 
    color: white;
    padding: 1rem 2rem;
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    flex-wrap: wrap;
}

header nav ul {
    list-style: none; 
    display: flex;
    gap: 20px; 
}

header nav a {
    color: white;
    text-decoration: none; 
    font-weight: bold;
}

#btn-modo-oscuro {
    background-color: #222;
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
}

/* =========================================
   3. SECCIONES PRINCIPALES Y DISTRIBUCION
   ========================================= */
main {
    padding: 2rem;
    max-width: 1200px; 
    margin: 0 auto;
}

.hero {
    text-align: center;
    background-color: #e9ecef;
    padding: 3rem 1rem;
    border-radius: 10px;
    margin-bottom: 3rem;
}

/* =========================================
   4. CATALOGO DE PRODUCTOS 
   ========================================= */
#productos h2 {
    text-align: center;
    margin-bottom: 2rem;
    font-size: 2rem;
}

.contenedor-productos {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.tarjeta-producto {
    background-color: white;
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    text-align: center;
    transition: transform 0.3s;
}

.tarjeta-producto:hover {
    transform: translateY(-8px);
}

.tarjeta-producto img {
    width: 100%;
    max-width: 200px;
    margin-bottom: 1rem;
}

.precio {
    font-size: 1.5rem;
    font-weight: bold;
    color: #0056b3;
    margin: 15px 0;
}

.btn-agregar {
    background-color: #28a745;
    color: white;
    border: none;
    padding: 12px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    width: 100%;
    transition: background-color 0.3s;
}

.btn-agregar:hover {
    background-color: #218838;
}

/* =========================================
   5. SECCIÓN DEL CARRITO
   ========================================= */
#carrito-seccion {
    margin-top: 4rem;
    background-color: #fff3cd;
    padding: 2rem;
    border-radius: 10px;
    text-align: center;
    border: 1px solid #ffeeba;
}

#carrito-seccion span {
    font-size: 1.5rem;
    font-weight: bold;
    color: #856404;
}

#btn-comprar {
    background-color: #0056b3;
    color: white;
    border: none;
    padding: 12px 30px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    margin-top: 20px;
}

/* =========================================
   6. PIE DE PAGINA
   ========================================= */
footer {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 1.5rem;
    margin-top: 3rem;
}

/* =========================================
   7. PREPARACION PARA JAVASCRIPT
   ========================================= */
body.dark-mode {
    background-color: #121212;
    color: #ffffff;
}

body.dark-mode .hero { background-color: #2a2a2a; }
body.dark-mode .tarjeta-producto { background-color: #1e1e1e; }
body.dark-mode .precio { color: #66b2ff; }
body.dark-mode #carrito-seccion { 
    background-color: #332b13; 
    border-color: #4a4123;
}
body.dark-mode #carrito-seccion span { color: #ffeb99; }

/* =========================================
   8. RESPONSIVE DESIGN
   ========================================= */
@media (max-width: 600px) {
    header {
        flex-direction: column;
        text-align: center;
        gap: 15px;
    }
    
    header nav ul {
        flex-direction: column;
        gap: 10px;
    }
}