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How to remove small border around edge of app.layout

I’m working on the UI for my application running on plotly dash. When I set the background color there is a small border area between the window and the layout that doesn’t get colored. How do I remove this? Or is there a way to have the color go all the way to the edge of the window?


I whittled the page to the basics…
import os
from flask import Flask
import dash
import dash_html_components as html

app.css.append_css({'external_url': ''})

server = Flask(__name__)
server.secret_key = os.environ.get('secret_key', 'secret')

app.layout = html.Div(
            [html.H1('Dashboard',className='six columns')],
    className='twelve columns',

if __name__ == '__main__':, threaded=True)

This is a result of the browser supplying a user agent style sheet with the <body> element having a default margin of 8px. You can override that if you want by attaching your own CSS style sheet with the following style:

body {
    margin-left: 0;
    margin-right: 0;

or if you want to get rid of all margins:

body {
    margin: 0;

Thank you very much! That did the trick.