First you need to understand RGB and ARGB they are actually both the same except the A is alpha blending a.k.a transparent. Now true RGB is 9 digits in decimal so for Red as a color it would look like this 255,000,000 R = 255 G = 000 B = 000 so for ARGB it would look like this 000,255,000,000 now ARGB can also be represented in hex 00..FF for each of the A,R,G,B so a simple decimal to hex conversion would produce 00,FF,00,00 (00ff0000) but because it is hex it is read in little endian format(reversed) so 00ff0000 becomes 0000ff00, now for html it is exactly the same as as RGB but in hex format and NOT reversed so RGB = 255,000,000 Html = FF0000 Hex = 0000FF ARGB = 0000FF00
I hope this helps to understanding colors…