1. canvasgradient api: addcolorstop

2. css property: stop-color

3. types: `calc()`: gradient color stops support

4. types: `<gradient>`: `conic-gradient()`: double-position color stops

5. types: `<gradient>`: `conic-gradient()`: single color stop and 0-1 positions

6. types: `<gradient>`: `linear-gradient()`: double-position color stops

7. types: `<gradient>`: `linear-gradient()`: single color stop and 0-1 positions

8. types: `<gradient>`: `radial-gradient()`: double-position color stops

9. types: `<gradient>`: `radial-gradient()`: single color stop and 0-1 positions

10. types: `<gradient>`: `repeating-conic-gradient()`: single color stop and 0-1 positions

11. types: `<gradient>`: `repeating-linear-gradient()`: double-position color stops

12. types: `<gradient>`: `repeating-linear-gradient()`: single color stop and 0-1 positions

13. types: `<gradient>`: `repeating-radial-gradient()`: double-position color stops

14. types: `<gradient>`: `repeating-radial-gradient()`: single color stop and 0-1 positions

15. global_attributes: stop-color