main.py

from fastapi import FastAPI
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles

app = FastAPI()
app.mount("/static", StaticFiles(directory="static", html=True), name="static")
app.mount("/img", StaticFiles(directory="img"), name="img")

@app.get("/")
def index() -> FileResponse:
    return FileResponse(path="/app/static/index.html", media_type="text/html")