By adding the `style` attribute to the `.o_layout` element it can be customized according to the data collected with `themeParams`, making it possible to add a custom background color in our template design, for example. See b7537e1d66b4ca26e12f4be16eb1c30632ecee61 closes odoo/odoo#83701 Signed-off-by: Antoine Guenet <age@odoo.com>