Dash not including the CSS file

Hello Dash users !

I started using dash and I am trying to include some css file. I tried to run the example provided in the documentation of Dash and unfortunately it seems that no formatting is included. I have included the name in dash. The assets folders is in the right place. I have respected exactly what’s on the documentation. If you have any ideas how to solve this I would be very grateful.


Hi @kimo

I never see this kind of problem.

If the assets folder is in the same folder than the app.py every css file included in the assets folder will be automatically executed, for example consider this files path:


Hi @Eduardo !!

Thank you so much for your reply !!.image

This is exactly how I organized the folder and the dash code (I put the screenshot attached).

For the code I am taking exactly the same as the documentation:


import dash
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash(name)

app.layout = html.Div([
html.Div(‘Plotly Dash’, className=“app-header–title”)
This is an example of a simple Dash app with
local, customized CSS.

if name == ‘main’:


body {
font-family: sans-serif;

h1, h2, h3, h4, h5, h6 {
color: hotpink

if you have any idea of what I could have done wrong please let know :slight_smile:

Hi @kimo

I have no idea, I take the example from the documantation and also create the example using “Dash_example.py” and it works:


Many thanks @Eduardo !

I have tried that on my personal computer and it is working too. when I tried that on my companies computer it does not really work :frowning:. the only diff is teh version of Dash (1.18.1) which should be fine to add the css