## 4 Results  
### Service Accessibility for the Elderly Within 5-min, 10-min, and 15-min CLCs  
For each elderly care facility, the accessibility of POI categories within walking time thresholds (5-, 10-, and 15-min) was systematically quantified. A facility is deemed to have access to a specific service type if at least one corresponding amenity of that category is reachable within the designated walking duration. Theoretically, an elderly care facility can achieve a maximum coverage of eight service types. Figure 4 illustrates the types of Points of Interest (POIs) accessible to elderly residents across 711 senior care facilities within three-tier walking catchment areas in Changsha. The spatial analysis reveals pronounced urban-rural disparities in walkability performance. Under the 15-min walking threshold, central urban facilities demonstrate superior accessibility: 91.4% of institutions access seven or more types of services, with 70.25% reaching 8 categories, forming high-accessibility clusters centered in Tianxin, Yuhua, and Furong Districts along the east bank of the Xiangliang River. This spatial pattern is closely associated with the high-density built environment and compact land use in older urban areas, demonstrating substantially improved accessibility metrics compared to newer West Bank developments. Notably, emerging secondary accessibility hubs in the Liuyang and Ningxiang regions manifest a \"core-satellite\" spatial configuration, potentially aligning with Changsha's polycentric development strategy. In contrast, township facilities exhibit markedly reduced accessibility--merely 26.86% achieve seven or more types of services within 15-min walks, displaying dispersed spatial distribution. When thresholds tighten to 10 min, 81.81% of urban facilities can still access seven types of services versus 18.89% in townships, where most facilities cover fewer than five types of services. Although spatial patterns resemble 15-min results, urban core service areas contract substantially. Crucially, the 10-min walking radius--representing seniors' high-frequency activity range--reveals acute service deficiencies in township areas. Further analysis under the 5-min walking threshold reveals that 42.32% of the facilities in the central urban area can access seven types of services, but 11.65% of the facilities still cover fewer than four types of services. In rural townships, service gaps are widespread, as service resources have not kept pace with suburban development, and most facilities can only cover one to two types of services. Spatial comparisons show that the 5-min walkability in the newly developed areas on the west bank of the Xiangjiang River is substantially lower than that in the older urban areas on the east bank, reflecting the insufficient density of life-service facilities in newly developed regions. This phenomenon suggests that planners need to prioritize optimizing the 5-min coverage network for frequently used facilities (such as medical services and convenience stores), particularly by establishing micro-living circles with basic service facilities in newly developed urban areas and rural townships. This study further identifies deficiencies in facility allocation by analyzing the accessibility of service categories under different walking time thresholds (Table 7). The data reveals that urban senior care facilities demonstrate substantial advantages in accessing three fundamental services (catering, medical care, and shopping) within central urban areas: over 90% of institutions can reach these facilities within a 10-min walking radius. Notably, the coverage rate of medical facilities reaches 90.37% under the 5-min walking threshold, highlighting the highly efficient distribution of urban healthcare resources. In contrast, rural township areas require improvement in medical service coverage--merely 59.8% of senior care institutions can access medical facilities within a 15-min walking radius.