app.py

import gradio as gr

def greet(name):
    return "Hello " + name + "!!"

with open("index.html", "r") as f:
    html_content = f.read()

with gr.Blocks() as demo:
    gr.HTML(html_content)
    with gr.Row():
        inp = gr.Textbox(placeholder="What is your name?")
        out = gr.Textbox()
    inp.submit(greet, inp, out)

demo.launch()