python flask login-form

By geo
python flask 
from flask_wtf import FlaskForm
from wtforms import StringField, SubmitField
from wtforms.validators import DataRequired
from flask import Flask, render_template

class LoginForm(FlaskForm):
    username = StringField("Username", validators=[DataRequired()])
    password = StringField("Password", validators=[DataRequired()])
    submit = SubmitField("Login")

app = Flask(__name__)
app.config["SECRET_KEY"] = "geo"

@app.route("/", methods=["GET", "POST"])
def index():
    form = LoginForm()

    if form.validate_on_submit():
        return f"Hello, {form.username.data}!"
    return render_template("login.html", form=form)

if __name__ == "__main__":
    app.run(debug=True)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Login</title>
    <style>
        .error { color: red; }
    </style>
</head>
<body>
    <h1>Login</h1>
    <form method="post">
        
        <p> : </p>
        <p> : </p>
        
        
        <p></p>
    </form>
</body>
</html>