Most color charts for HTML give the 'colorname' as three hex digits, certainly useful if you are doing web pages. However if you are using a web 'color' in a pdf file (by way of LaTeX), a little bit of conversion is in order. Here is a short script that does the necessary for you:

#!/perl/bin/perl
#
# rgb.pl -- given a color name and a hex string of 6 digits
# in typical html order, convert to a \definecolor string for
# LaTeX's color.dvi package.
#
use strict;
use warnings;
use diagnostics;

my $color = ($ARGV[0] or "xx");
$ARGV[1] =~ /(..)(..)(..)/;
my $r = hex($1);
my $g = hex($2);
my $b = hex($3);

$r /= 256.00;
$g /= 256.00;
$b /= 256.00;

print "\\definecolor{$color}{rgb}{$r,$g,$b}\n";
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--hsm