light blue
縹 centers on a specific pale blue color, often associated with delicate fabrics or light blue dyes.
縹 combines 糸 (thread/silk) with 票, which likely contributes the sound. The character originally referred to a light blue silk or dye.
The left side 糸 suggests thread or fabric, and the right side 票 looks like a ticket or label. Imagine a bolt of silk labeled with a ticket that reads 'light blue' — the color of the fabric.
For ヒョウ, picture a hyō (雹, hail) stone dyed light blue: hyō -> ヒョウ, and the hail's pale blue color matches the silk.