Help me improve my sleep.

Current sleep duration: {{duration}}
Issues: {{issues}} (trouble falling asleep, waking up, light sleep, early waking, daytime fatigue)
My bedtime routine now: {{current_routine}}
My bedroom environment: {{environment}} (light, noise, temperature)
Caffeine and alcohol intake: {{caffeine_alcohol}}
Stress level lately: {{stress}}
Screen use before bed: {{screens}}

Return:
1. The most likely 2-3 root causes based on what I shared
2. A new wind-down routine — last 90 minutes before bed
3. Environment changes — what to fix in my bedroom
4. Daytime habits that affect night sleep
5. What to do if I wake up at 3am and can't fall back asleep
6. The single highest-impact change for my situation
7. What to track for the next 2 weeks to know it's working
8. When to consult a sleep doctor

Not medical advice. Flag medical red flags.