In a large mixing bowl, combine the broccoli, cauliflower, carrots, red onion, bacon, sunflower seeds, and raisins. Toss gently to mix all the ingredients evenly.
In a separate small bowl, whisk together the mayonnaise, apple cider vinegar, sugar, salt, and pepper until smooth.
Pour the dressing over the salad mixture and stir until all the ingredients are well coated.
Cover the bowl with plastic wrap and refrigerate for at least 1 hour to allow the flavors to meld.
Before serving, give the salad a good stir and adjust seasoning if necessary.