## 1 Introduction  
Recent research has highlighted a growing mental health crisis amongst young people globally, with increasing rates of anxiety and depression [1]. Young people are one of the groups most affected by mental health challenges, often feeling overwhelmed by uncertainties about their future, academic burdens and strained relationships [2]. These emotional struggles are further compounded by societal and familial expectations that push young people to excel academically, secure employment in a competitive job market and conform to the influences of social networks [3]. The combination of these pressures can lead young people to experience intense self-doubt, diminished self-worth and emotional distress, ultimately contributing to mood swings and mental health issues [4]. Given the growing prevalence of these emotional challenges, effective emotion regulation has become essential for helping young people manage their mental well-being. Emotion regulation refers to the psychological process by which individuals use physiological, cognitive and behavioural strategies to manage their emotions in response to internal and external demands [5]. This process is crucial in helping individuals cope with negative emotions and maintain emotional stability when facing external pressures. Importantly, emotion regulation during adolescence and early adulthood reflects not only immediate coping behaviour but also ongoing neurobiological and social development. The maturation of the brain during this period supports improvements in cognitive control and decision-making [6]. In parallel, relationships with parents and peers influence young people's emotion regulation and adjustment [7]. For young people, emotion regulation depends largely on their ability to self-regulate and select appropriate tools or products to assist in managing their emotions. These developmental and contextual factors likely shape how young people experience emotional challenges and how they perceive and engage with emotion regulation products. Because emotional difficulties increasingly affect daily life, research on emotion regulation has expanded across various disciplines, including psychology, neuroscience, digital health and social science [8]. Current research on emotion regulation focuses on the neural mechanisms behind emotion regulation through neuroimaging techniques such as functional magnetic resonance imaging [9], examining the role of emotion regulation in mental health disorders such as depression and anxiety [10] and investigating resilience-building tools like positive thinking and emotion tracking applications [11; 12]. With the increasing impact of emotional challenges on people's well-being, the need for practical measures to support emotional support strategies has led to the integration of advanced technologies. In particular, the application of artificial intelligence (AI) technology has begun to play an increasingly prominent role in emotion regulation [13]. AI technology refers to machines that can perform human behaviours or create computer programs [14]. The role of AI technology in emotion regulation is mainly to identify, regulate and analyse emotions [15; 16]. Integrating AI technology into emotion regulation products transforms the landscape of emotional well-being solutions, offering personalised and adaptive interventions to help individuals manage their emotions effectively [17]. AI technology in emotion regulation can be grouped into three main categories. First, AI technology is used for emotion detection, where AI-driven interfaces, applications and chatbots adapt their responses based on emotional cues, providing empathetic and supportive interactions [18]. For instance, Woebot, an AI-powered therapeutic chatbot, helps users identify and manage their emotions through cognitive behavioural therapy-based techniques [19]. Second, AI technology combined with wearable devices track and analyse mood data, predicting mood fluctuations and helping manage mood disorders [20].