rgb 72, 61, 139 is an html colour code. Dark Slate Blue
I don't think this vBulletin has html as "allowed" ??
Ahh, bottom left of screen - HTML code is Off
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Looked for info about it. RGB is RGB colour code (red green blue and all the shades in between).
HTML for Dark Slate Blue is 483D8B
http://instant-eyedropper.com/info/html_color_code/
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Sorry for my tangent.