How to change the background color of the html page?

Hello,

What is the html command to change the background color please?

As you can see on the image the body is the yellow part, and the blue is the dashboard. I can only change the color of the dashboard so far.

I tried :

html.Tbody(
    style={'background-color': 'pink'}
)

app = Dash(__name__)

app.layout = html.Div(
    className='dashboard',
    etc...

I also tried to add this part of code, to see if it would import a css file, but nothing happens :

assets_path='./assets/style.css'

app = Dash(__name__, assets_folder=assets_path)

Thank you.

Ok after tinkering a lot with the css files I found that app = dash.Dash(__name__) is used to include css files instead of app = Dash(__name__)