Colloquial and very common online — used to praise small kind gestures, especially in news headlines about
暖心故事 (nuǎnxīn gùshi, heartwarming stories) and
暖心举动 (nuǎnxīn jǔdòng, heartwarming acts). Marketing copy uses
暖心服务 (nuǎnxīn fúwù, considerate service) constantly.