Meaning of まっ in Japanese

枝葉末節の議論はもうそろそろ止めにして、本筋の話に移りませんか。
Why don't we stop arguing over these piddling matters and get to the issues at hand?

外は真っ暗だった。
It was pitch black outside.

いつも真っ向勝負だけでなく、たまには虚虚実実の駆け引きとやらもやってみたいよね。
We have to be ready not only for a straightforward test of strength, but also for a struggle in which every strategy comes into play.

コンサートの真最中に劇場を出なければならなかった。
I had to leave the theatre in the middle of the concert.