The words opposite and across from mean that something is located at the other side of something.

The bank is opposite the post office. or The bank is across from the post office.

Henry sat opposite me at the table. or Henry sat across from me at the table.

The expression in front of simply means that one thing is closer to a point of reference (the "front" of an area, or the point of view of the person looking).

I stood in front of the bank.

He sat in front of me in the classroom.

The word before can be used for location/position, but it is somewhat rare and more formal. Instead, before is typically used for time or for position in a sequence:

We need to pack our bags before leaving for the airport.

The letter i comes before the letter e in the word "friend." or position in a sequence

SuperFood

Blueberries Dried

Blueberries rank first among 40 antioxidant-rich fruits and vegetables, with a potent mix of flavonoids, tannins, and anthocyanins. Dried blueberries provide many of the Benefits of fresh ones, with the addition of more fiber. They are a terrific portable snack!
Nutritional Facts :
One-third cup of dried blueberries provides 140 calories, 33 g carbohydrate, 1 g protein, 0 g fat, 4 g dietary fiber, and 6 mg vitamin C.