What do I do when my MacBook Pro starts up to a black screen?

A couple days ago i was using my macbook pro, and it died. It showed the low battery symbol indicating that it needed to be charged. I charged it yesterday and today when I tried to power it on, I can see that the keyboard is lit but the screen remains black. It also charges my phone fine without the laptop charger in so i know it has power. But the screen will not come up. How can i fix this? I need help.

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