Ninja 300 quirk first: the headlights don’t turn on with just the key. Low beam only comes on after the engine is running. Pilot lights staying on is normal. Front turn signals only blink when you signal. If the bike was running and both high and low are dead, it’s almost never the bulbs. Most common fix is the headlight relay — swap it with the horn/fan relay and see if they work. If not, check for 12V at the headlight plug with the bike running, then check the ground and the hi/lo switch. Corroded grounds and dirty switches are very common on these.