Right 色 — the indexing radical, meaning color or attractive appearance. Together: lushness + color = vivid, gorgeous, glamorous. Captures the ripe-and-radiant flavor of 艳, whether describing flowers, sunsets, or a striking outfit.
Left 丰 — abundance, lushness, growth in full bloom. The character pictures a plant heavy with foliage. In simplified 艳 it stands in for the much more elaborate left half of traditional 艷, condensing the idea of overflowing fullness.
