Participants will utilize the specific sleep program available within the app, which will include a choice of audio soundtracks for guided MM (no exposure to screen lights during practice). The practice may involve techniques such as breathing exercise, imagery, body scan, and relaxation. Participants will specifically use the app during the immediate pre-sleep period. They can choose their preferred meditation sessions within the Sleep menu in Week 1-4.

Participants will be asked to practice MM using the same app during daytime (prior to the evening meal), but without specific study instructions around components to access or specific time of practice.

Participants will receive sleep hygiene education and asked not to start any new insomnia treatments. Sleep hygiene education serves as a minimal intervention control condition and real-world comparator. At the end of the study, interested participants in the control group will be given equal access to the mobile app. Usual care for insomnia typically involves sleep hygiene education, so all three groups will receive standard SHE as part of usual care.

All participants will access the a smartphone app, and the mindfulness meditation practice may involve techniques such as breathing exercise, imagery, body scan, and relaxation. The investigators will provide instructions for participants who are assigned to practice at bedtime.

The proportion of screened participants who were determined to be eligible for the study; calculated as the number of eligible participants divided by the total number of individuals screened.

Retention rate is defined as the percentage of participants who complete the entire follow-up period. Reasons for participant dropout will also be documented.

In the intervention groups, a mindfulness meditation session ≥ 10 minutes will be considered as a completed session. Numbers of sessions completed during the four weeks will be recorded. Adherence to intervention protocol will be defined as those randomized to the intervention groups complete ≥ 70% of home practice.

Compliance with outcome assessment will be determined by the percentage of participants who complete ≥ 70% of questionnaires at each time point.

At intervention end (week 4), a brief questionnaire will ask participants to rate (1=not at all to 5=very much) the enjoyableness, convenience, helpfulness, and overall satisfaction with the app-based mindfulness practice. Acceptability is assessed by self-report survey ratings, and a threshold of 80% ratings of 4 or higher will indicate acceptability.

Insomnia severity will be assessed by the Insomnia Severity Index (ISI), a brief instrument that assesses insomnia. Its reliability, validity, and sensitivity to treatment response have been documented in the general population and with patients with insomnia. The total score ranges from 0 to 28, and higher scores indicate more severe insomnia. This secondary/exploratory outcome will be summarized with simple descriptive statistics without formal efficacy testing.