body {
    font-family: Arial, sans-serif;
    background: #f7f7fa;
    margin: 0;
    padding: 0;
}
.container {
    max-width: 960px;
    margin: 40px auto;
    background: #fff;
    padding: 30px 40px;
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}
h1 {
    color: #3498db;
    text-align: center;
    margin-bottom: 30px;
}
h2 {
    color: #555;
    margin-top: 30px;
    margin-bottom: 15px;
}
.datos-generales {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    margin-bottom: 20px;
    align-items: center;
    padding: 15px;
    border: 1px solid #ddd;
    border-radius: 8px;
    background-color: #f9f9f9;
}
.datos-generales label {
    min-width: 120px;
    font-weight: bold;
}
.datos-generales input,
.datos-generales select {
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 4px;
    flex-grow: 1;
    width: auto;
    box-sizing: border-box;
}
.navbar {
    width: 100%;
    background: #3498db;
    padding: 10px 0;
    display: flex;
    justify-content: center;
    gap: 30px;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.navbar a {
    color: #fff;
    text-decoration: none;
    font-weight: bold;
    font-size: 18px;
    padding: 8px 18px;
    border-radius: 4px;
    transition: background 0.2s;
}
.navbar a:hover, .navbar a.active {
    background: #2980b9;
}
.tabla-responsive {
    width: 100%;
    overflow-x: auto;
    margin-top: 20px;
}
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 20px;
    min-width: 700px;
}
table th, table td {
    border: 1px solid #ddd;
    padding: 12px 8px;
    text-align: left;
}
table th {
    background: #3498db;
    color: #fff;
    text-align: center;
    font-weight: bold;
}
table tbody tr:nth-child(even) {
    background-color: #f2f2f2;
}
table td input[type='number'],
table td input[type='text'] {
    width: 80px;
    padding: 4px;
    border: 1px solid #ccc;
    border-radius: 4px;
}
table input[readonly] {
    background: #eee;
    opacity: 0.8;
}
button {
    background: #e67e22;
    color: #fff;
    border: none;
    padding: 10px 20px;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.2s;
    font-size: 16px;
}
button:hover {
    background: #cf711f;
}
#mensaje {
    margin-top: 20px;
    text-align: center;
    font-weight: bold;
    padding: 10px;
    border-radius: 4px;
}
.eliminar {
    background: #e74c3c;
}
.eliminar:hover {
    background: #c0392b;
}
.guardar-btn {
    background: #27ae60;
}
.guardar-btn:disabled {
    background: #aaa;
    cursor: not-allowed;
}
.guardar-btn:hover:not(:disabled) {
    background: #219150;
}
.filtros {
    margin-bottom: 20px;
    display: flex;
    gap: 20px;
    align-items: center;
    flex-wrap: wrap;
    padding: 15px;
    border: 1px solid #ddd;
    border-radius: 8px;
    background-color: #f9f9f9;
}
.filtros label {
    font-weight: bold;
}
.filtros input {
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 4px;
}
.formulario-proveedor {
    margin-bottom: 30px;
    padding: 20px;
    border: 1px solid #ddd;
    border-radius: 8px;
    background-color: #f9f9f9;
}
.formulario-proveedor div {
    margin-bottom: 15px;
}
.formulario-proveedor label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}
.formulario-proveedor input[type="text"], .formulario-proveedor input[type="submit"] {
    width: calc(100% - 18px);
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 4px;
}
.formulario-proveedor input[type="submit"] {
    width: auto;
    background-color: #3498db;
    color: white;
    border: none;
    cursor: pointer;
    padding: 10px 20px;
    transition: background-color 0.3s ease;
}
.formulario-proveedor input[type="submit"]:hover {
    background-color: #2980b9;
}
.listado-proveedores {
    margin-top: 30px;
}
.filtro-proveedores {
    margin-bottom: 15px;
}
.filtro-proveedores input {
    padding: 8px;
    width: calc(100% - 18px);
    border: 1px solid #ccc;
    border-radius: 4px;
}
.generate-barcode-btn {
    background: #3498db;
    padding: 8px 16px;
}
.generate-barcode-btn:hover {
    background: #2980b9;
}
@media (max-width: 768px) {
    .container { padding: 20px 15px; }
    .navbar { gap: 15px; padding: 8px 0; }
    .navbar a { font-size: 16px; padding: 6px 10px; }
    .datos-generales {
        flex-direction: column;
        gap: 10px;
        align-items: stretch;
        padding: 10px;
    }
    .datos-generales label {
        min-width: auto;
    }
    .datos-generales input,
    .datos-generales select {
        width: 100%;
        box-sizing: border-box;
    }
    #costo_envio {
        width: 120px;
        flex-grow: 0;
    }
    #productosTable {
        min-width: 400px;
    }
    #productosTable th, #productosTable td { padding: 8px 4px; }
    #productosTable td input[type='text'],
    #productosTable td input[type='number'] {
        width: 60px;
        box-sizing: border-box;
    }
    #productosTable td button.eliminar {
        padding: 4px 8px;
    }
    .filtros {
        flex-direction: column; gap: 10px; align-items: stretch; padding: 10px;
    }
    .filtros input {
        width: 100%; box-sizing: border-box;
    }
    table { font-size: 12px; min-width: 500px;}
    table th, table td { padding: 6px; }
    table td input[type='number'],
    table td input[type='text'] { width: 60px; }
    .formulario-proveedor input[type="text"], .filtro-proveedores input { width: calc(100% - 16px); }
}