Add a warm, mellow upright-style bass to this cozy rainy cafe lo-fi hip-hop track. Keep all existing parts unchanged: drums, electric piano, guitar, vocals and rain ambience. Rounded, woody tone with soft attack and short natural decay. Lock to the kick and follow the chord changes with relaxed, slightly behind-the-beat lines and subtle swing. Mostly roots and fifths, with occasional gentle walking passages and chromatic approach notes into chord changes. Keep it sparse and supportive, leaving space around vocal phrases and piano fills, never competing with the melody. Add small slides, light ghost notes and soft finger noise for a played-live feel. Match the track’s tape texture with gentle saturation and a soft low-pass filter. Sit warmly under the mix, round and full but never boomy, without masking the kick. Keep dynamics steady and calm throughout, including the loop point.