Warm, dim light, think amber, red, and orange tones, is best in the evening. These warmer colors contain little blue light, so they don't suppress melatonin the way bright white or blue-rich light does. That's why warm lamps and "night mode" help you wind down.
The flip side matters too: in the morning and during the day you want bright, cool, blue-rich light (ideally sunlight) to feel alert and anchor your body clock. So the rule of thumb is cool and bright by day, warm and dim by night.
