Fix ZCAM domain error corner case

Author: facelessuser

coloraide/spaces/zcam_jmh.py

@@ -346,7 +346,7 @@ def xyz_d65_to_zcam(xyzd65: Vector, env: Environment, calc_hue_quadrature: bool
     Cz = 100 * (Mz / env.qzw)
 
     # Step 16
-    Sz = 100 * (env.fl ** 0.6) * math.sqrt(Mz / Qz) if Qz else 0.0
+    Sz = 100 * (env.fl ** 0.6) * alg.nth_root(Mz / Qz, 2) if Qz else 0.0
 
     # Step 17
     Vz = math.sqrt((Jz - 58) ** 2 + 3.4 * (Cz ** 2))

docs/src/markdown/about/changelog.md

@@ -17,6 +17,7 @@
         recreate the aforementioned pre-configured methods themselves or their own desired variants.
 
 -   **FIX**: HWB and HSV cannot normalize hue and saturation the same way as HSL when saturation is negative.
+-   **FIX**: Fix corner case in ZCAM that could throw a domain error.
 
 ## 3.3.1