Color Converter
HEX ↔ ARGB integer ↔ rgba()
HEX with alpha
The short form #RGB is accepted once you finish typing. Six digits are RRGGBB,
eight include alpha in the selected order. The # sign and 0x are optional.
An ARGB integer is what Color.ToArgb() returns in .NET: from -2147483648
to 4294967295.