How do We Know for Certain the Election was not Stolen?

  Election systems in all 50 states were targeted for hacking? But, none were believed compromised? Some attacks leave no trail. The hacker designs them so the evidence is erased. We might suppose none were compromised, but I am wondering if there is no way of knowing that for certain.
  And, if this is true, we cannot know for certain that the election was not stolen. That does not mean President Trump stole it, but it does mean someone might have stolen it for him.