Please listen to this section with a very gentle attitude. Insomnia doesn't mean you're not trying hard enough, nor does it mean you lack willpower. Often, it's because your body is still tense, the daytime stress hasn't truly dissipated, or your sleep schedule, environment, and thoughts are keeping your brain in a waking state. This section's theme is "Circadian Rhythm Disorder and Biological Clock Disruption." Understanding circadian rhythms and the biological clock will help your body know when to be awake and when to rest. This isn't about solving all your problems immediately, but about first removing sleep difficulties from confusion and self-blame, placing them in a position where they can be observed and adjusted. When learning, please begin with gentle observation. Observe whether your wake-up time, light exposure, eating, exercise, and pre-sleep activities fluctuate significantly each day. If you only focus on "Why can't I fall asleep yet?", anxiety will intensify; if you can see the clues before and after, sleep will no longer be just an uncontrollable outcome. Next, please choose a small and stable exercise. Use a fixed wake-up time, morning light exposure, and gradually advance your sleep schedule to slowly correct your disrupted rhythm. Don't make the changes too complicated; the simpler and more repeatable the changes, the easier it is for your nervous system to slowly rebuild a sense of security. The course content cannot replace assessments by doctors, psychologists, or sleep specialists, but it can help you record, communicate, and seek help more clearly. After listening, please write down one observation that resonated with you today, and a small action you're willing to try. It can be small, such as setting a fixed wake-up time, putting your phone down earlier, recording the number of times you wake up at night, or doing three minutes of breathing exercises before bed. Repeating these small steps will help your body gradually learn a new rhythm. Your daytime rhythm, your evening environment, and your pre-sleep thoughts can all be gradually adjusted. When anxiety rises, return to your breathing, your body, and the present moment, rather than continuing to chase sleep. Stable sleep isn't about forcing yourself, but about accompanying your body step by step back to a regular rhythm. If you only manage to do a little bit today, please acknowledge that you are already taking care of yourself. Give your body some time; it needs to relearn the night through repeated safe experiences. Don't see missing a night as a failure; it's simply a signal that needs gentle observation.