Предположим, у вас есть приложение flask с именем myblog.py и следующей структурой каталогов:
assets is the static directory.
myblog.py code looks like this:
from flask import Flask, render_template
app = Flask(__name__,
static_url_path='',
static_folder='app/assets',
template_folder='app/templates')
@app.route('/')
def index():
return render_template("index.html")
In index.html you access the static css file like this: