John doesn't say there's light in God, or that God has a light side. He says God IS light, completely, with no darkness mixed in anywhere. That's different from how you probably think about it — like light and dark are two settings on a dimmer switch and you're somewhere in the middle depending on your mood. Darkness, in this sense, isn't a place you visit on a bad day. It's a direction — it's living like God isn't actually who he says he is, even while you'd say out loud that you believe he is. Proverbs says people in that darkness don't even know what they're tripping over, which is the scary part — you can be stumbling and not know it's happening.
Think about it
Name one specific area of your life right now where you're treating what God says as optional or 'it depends' instead of just true. What would actually standing in the light look like there this week?