## 1 Introduction
However, these methods were limited by high costs, small sample sizes and insufficient spatiotemporal resolution, which restricted a thorough understanding of the dynamic features and developmental trajectories of urban vitality [10; 11]. Subsequent studies have used point of interest (POI) data to represent spatial distribution patterns of urban functions and their impact on regional vitality [12], but POI data often lacks timeliness and objectivity, providing onlya partial view of actual human activity levels and failing to accurately capture urban vitality [13]. The advancement of information technology has enabled more effective analyses of urban vitality. Compared to traditional survey methods, multi-source data offer finer-grained observations, broader coverage and richer spatiotemporal and semantic information, rendering them particularly suitable for characterizing urban vitality from a human perspective. Consequently, mobile phone signaling data, remote sensing data and online review data have been widely employed to measure urban vitality, facilitating detailed examinations of its spatiotemporal dynamics [14; 15; 16; 17]. For instance, [PERSON] et al. showed that satellite-based nighttime light data can accurately capture the dynamic patterns and intensity of urban population activities [18]. [PERSON] pinpointed hotspots of online activity by analyzing Wi-Fi data, assessing the vibrancy of urban spaces through the lens of digital connectivity [19]. [PERSON] et al. extracted spatial vitality at 24 intervals throughout the day from mobile phone signaling data, creating a vitality time series for urban blocks and interpreting urban vitality from a temporal dimension [17]. Research on the vitality of various urban areas has garnered significant attention [20]. In China, subdistricts serve as fundamental administrative units [21], and findings derived from this scale are more operational and scientifically robust, yielding critical insights to inform urban development and enhance the built environment. Employing the block as the unit of analysis accurately reflects urban vitality's micro-scale spatial attributes and its connection to the built surroundings, thereby addressing the precision limitations associated with larger administrative regions and the over-arching perspectives lacking in smaller grid scales. Quantitative assessment of urban vitality at the subdistrict and block levels enhances the understanding of both overall and regional development, systematically revealing the hierarchical characteristics of urban vitality through macro patterns and micro mechanisms. Such insights can inform future urban activities, planning and construction initiatives [22; 23]. The built environment of a city is recognized as a critical factor influencing urban vitality [24]. Researchers utilize a range of built environment indicators of different dimensions to examine urban vitality influences. Elements such as spatial configuration [25], development and construction [26] and supporting facilities [20] are recognized as closely associated with urban vitality and are frequently represented by one or a limited number of indicators. For example, [PERSON] et al. found that an increase in the density of road intersections can enhance the accessibility of a road network in a certain area, which to some extent can promote urban vitality [27]. [PERSON] et al. argued that higher development intensity and greater spatial compactness have a significant positive impact on urban vitality [28]. [PERSON] pointed out that the accessibility of urban facilities is the most important environmental factor for enhancing urban livability [29]. [PERSON] et al. introduced a \"3D\" framework for evaluating the interplay between the constructed environment and transportation [30]. [PERSON] et al.