body {
    font-family: system-ui, -apple-system, sans-serif;
    margin: 0;
    padding: 1rem;
    background: #f8fafc;
    color: #1e293b;
}

/* Layout principal de 3 columnas */
.app-layout {
    display: grid;
    grid-template-columns: 250px 1fr 300px;
    gap: 1.5rem;
    align-items: start;
    max-width: 1400px;
    margin: 0 auto;
}

/* Columnas laterales pegajosas */
.sidebar-left, .sidebar-right {
    position: sticky;
    top: 1.5rem;
    background: #fff;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    max-height: calc(100vh - 3rem);
    overflow-y: auto;
}

.main-content {
    background: #fff;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

/* Grilla de productos interna (min 240px por tarjeta) */
.product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

/* Tarjetas de producto */
.product-card {
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    background: #fff;
    transition: transform 0.2s;
}
.product-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

.product-card img {
    width: 100%;
    height: 180px;
    object-fit: contain;
    border-radius: 4px;
    margin-bottom: 0.5rem;
    background: #f1f5f9;
}

.sku { font-size: 0.8rem; color: #64748b; }
.product-card h4 { margin: 0.5rem 0; font-size: 1.1rem; line-height: 1.2; }
.price-stock { display: flex; justify-content: space-between; align-items: center; margin: 0.5rem 0; }
.precio-destacado { color: #2e7d32; font-weight: 700; font-size: 1.25rem; }
.stock { font-size: 0.85rem; font-weight: 500; }

/* Controles de compra */
.buy-box { display: flex; gap: 0.5rem; margin-top: 1rem; }
.buy-box input { width: 70px; padding: 8px; text-align: center; border: 1px solid #cbd5e1; border-radius: 4px; font-weight: bold; }
.btn-agregar, .btn-wsp, .btn-vaciar { border: none; padding: 10px; border-radius: 6px; cursor: pointer; width: 100%; font-weight: bold; text-align: center; text-decoration: none; display: block; box-sizing: border-box; }
.btn-agregar, .btn-wsp { background: #25d366; color: white; }
.btn-vaciar { background: #ef4444; color: white; margin-top: 1rem; }
.btn-del { background: none; border: none; cursor: pointer; font-size: 1.2rem; }

/* Filtros */
.filters-container { display: flex; flex-wrap: wrap; gap: 1rem; align-items: center; margin-bottom: 1rem; padding-bottom: 1rem; border-bottom: 1px solid #e2e8f0; }
#input-busqueda { padding: 10px; border: 1px solid #cbd5e1; border-radius: 6px; width: 100%; max-width: 350px; font-size: 1rem; }
.cart-item { display: flex; justify-content: space-between; align-items: center; margin-bottom: 1rem; border-bottom: 1px solid #f1f5f9; padding-bottom: 0.5rem; }