Your MacBook is not turning on which may be caused by a drained battery, display issues, faulty charging, startup disk corruption, etc.
Here are some methods for you to fix your MacBook not turning on.
Method 1: Fully charge your MacBook. You mentioned that your MacBook remained about 70 percent charged last night but it is not turning on today. It's possible that your MacBook power has run out overnight, so we advise you to charge it for a longer time and then try to restart it again.
Method 2: Check the power connection. If you incorrectly connect your MacBook to the power, it may cause your MacBook not to charge and then not turn on. At the same time, check whether your power cable is intact. If not, change to a new one and then try again.
Method 3: Disconnect all external devices. Bad contacts, short circuits, or consuming an unusual amount of energy might prevent your MacBook to turn on. Disconnect all external devices and then try to start your MacBook again.
Method 4: Reset SMC. SMC controls the entire MacBook power-on process. If the SMC has failed to receive power or assign a power supply to the hardware circuit, your MacBook won't turn on. So reset SMC and then restart your MacBook to check whether it can turn on normally.
Method 5: Run a power cycle. If your MacBook is Intel-based, you can try this method to force cut the power and then force restart your MacBook.
Method 6: Check your display. If you have turned down the brightness of your screen to the lowest by accident, your MacBook will look like not turning on. So press F1 or F2 to try turning up the brightness.
Method 7: Send it to repair. If you've tried all the above methods, but you still can't turn on your MacBook, the problem might be on the main logic board and you need to send your MacBook to repair.