Participants allocated to this arm will receive access to and use the Heart Voice: Starry Journey mobile application, a digital interactive narrative intervention based on Acceptance and Commitment Therapy (ACT) and designed from a family-centric cultural perspective. The intervention period is 6 weeks. Participants are instructed to engage with the application by progressing through its core narrative chapters and completing embedded interactive exercises (e.g., metaphor-based training, perspective-shifting tasks, and values clarification activities). They will complete the program at their own pace on their personal smartphones. In addition to using the application, participants in this arm will complete all scheduled study assessments.

Participants allocated to this arm will not receive the Heart Voice: Starry Journey intervention during the active trial period. They will be instructed to continue with their usual care and routines for the duration of the study. They will complete all scheduled study assessments at the same time points as the Intervention Arm. Upon completion of the final follow-up assessment for the entire trial, participants in this arm will be granted full access to the Heart Voice: Starry Journey application.

This intervention is a culturally adapted, digitally delivered interactive narrative program based on Acceptance and Commitment Therapy (ACT) for primary caregivers of children with autism. Distinguishing features include its family-centric design, which integrates ACT's core processes into scenarios simulating intergenerational decision-making and social stigma. Delivered via a mobile application over 6 weeks, it employs a branching narrative where user choices affect outcomes, a dynamic perspective-shifting mechanism between family members, and interactive metaphor-based modules (e.g., "Quicksand" for acceptance). Its development was validated through a Delphi expert consensus process, specifically tailoring content to the psychosocial stressors of caregivers in family-oriented cultural contexts.

Psychological flexibility was assessed using the Comprehensive Assessment of Acceptance and Commitment Therapy Processes (CompACT) questionnaire developed by Francis et al. This study employed the Chinese version translated by Fang et al. The scale consists of 23 items across three dimensions: Openness, Awareness, and Action. It uses a 7-point Likert scale ranging from "Never" to "Always," scored from 0 to 6, with higher total scores indicating a greater level of psychological flexibility.

Developed by Roskam et al. to assess parenting burnout levels. There are 23 items in the scale, which are divided into four dimensions: the sense of exhaustion of the parental role, the boredom of the parental role, the emotional alienation from the children, and the self-comparison with the previous parental role. Scores range from 23-161. Higher scores indicate higher levels of parental burnout.

Caregiver needs and resources were assessed using the Caregiver Needs and Resources Assessment (CNRA) scale developed by Li et al. The scale consists of 36 items across two dimensions (Needs and Resources) and 12 domains, with 2 of the items being reverse-scored. It employs a 5-point Likert scale ranging from "Never" to "Extremely Much," scored from 1 to 5. Higher scores indicate more pronounced levels of the corresponding needs or resources.

Autism knowledge was assessed using the Chinese version of the Autism Stigma and Knowledge Questionnaire (ASK-Q) revised by Zhai, which is adapted from the original instrument developed by Harrison et al. This revised version excludes the "stigma" dimension and focuses solely on knowledge assessment. The scale consists of 47 items across three dimensions: Diagnosis/Symptoms, Etiology, and Intervention. It employs a dichotomous scoring method, with "Correct" answers scored as 1 point, and "Incorrect" or "Don't Know" answers scored as 0 points. The total score ranges from 0 to 47, with higher scores indicating a better understanding of autism-related knowledge.

The feasibility assessment tool was developed by the researchers based on the system content and employs a mixed-method approach combining structured scales with open-ended feedback. The quantitative component uses a 7-point Likert scale to measure participants' overall satisfaction with the program. Additionally, subjective open-ended questions are included to gather qualitative feedback. Core prompts include: "Which part of the story impressed you the most, and why?" "What was the most helpful component of the program?" "What specific support did you gain from using the system?" and "What changes have you noticed in yourself after using the system?" Finally, an open-ended text box is provided to collect participants' overall experiences, suggestions for improvement, and any additional comments.