Is eating midnight bad for you?

No it all depends on when you sleep and what you're eating. If your schedule only allows you to eat THAT late. It all depends.

if you're hungry eat healthy foods

Try not to eat anything after 9pm in the night. Especially avoid heavy carb loaded foods.

No. Midnight can be good with Mayo.

It is bad for you to eat at midnight but it is good to drink 1/2 cup of pure water. Before you sleep, keep a copper or silver ware vessel filled with boiled water at room temperature near your bed. Have around 2-3 cups of this water in between your night sleep duration of 7 to 8 hours. Have a light dinner at around 7 or 8 pm and keep a gap of 2 hours between sleep and dinner. Food needs time to digest properly before you sleep. During sleep the gastrointestinal system function is markedly reduced most of the time. In the supine position-Salivation, swallowing rate, upper esophageal sphincter pressure and number of primary esophageal contractions have all been shown to be reduced during sleep. When you eat dinner early or keep sufficient gap between sleep and food, it allows your body the time to digest food properly and keep the acidic contents of the stomach rising back up into your oesophagus.

I'm not sure. What's in midnight? Does it taste good? Not too much sugar and refined junk?

It depends on you. Sometimes food can sit and ferment in your stomach because digestion has slowed down. If you're going to eat, eat veggies, maybe some meat, yogurt, gluten free grains (brown rice, oats, quinoa etc), and avoid anything that would cause inflammation. Your body has to heal at night.

depends if it is rubbish food