SafeThinker: Reasoning about Risk to Deepen Safety Beyond Shallow Alignment. - Xianya Fang; Xianying Luo; Yadong Wang; Xiang Chen 016; Yu Tian; Zequn Sun 001; Rui Liu; Jun Fang; Naiqiang Tan; Yuanning Cui; Sheng-Jun Huang (CoRR, 2026)