Worked example:
var/mytext = "Hello BYONDers"
I want Hello to be red and BYONDers to be blue.
var/mytext = "[fred]Hello[fend] [fblue]BYONDers[fend]"
End result:
src << mytext
This is the code you need to add to each dm file that uses colors. The colors you don't want to use can be missed out but fend is very important as it's what signals where a color stops.
// Colors
// Usage: var/mytext = "[fblue]hello[end]"
#define fblack "<font color=black>"
#define fsilver "<font color=silver>"
#define fgray "<font color=gray>"
#define fwhite "<font color=white>"
#define fmaroon "<font color=maroon>"
#define fred "<font color=red>"
#define fpurple "<font color=purple>"
#define ffuchsia "<font color=fuchsia>"
#define fmagenta "<font color=magenta>"
#define fgreen "<font color=green>"
#define flime "<font color=lime>"
#define folive "<font color=olive>"
#define fgold "<font color=gold>"
#define fyellow "<font color=yellow>"
#define fnavy "<font color=navy>"
#define fblue "<font color=blue>"
#define fteal "<font color=teal>"
#define faqua "<font color=aqua>"
#define fcyan "<font color=cyan>"
#define fend "</font>"
It's very simple and all you need is a website that has a color picker on it. Like this one: http://www.thehtmlguide.com/color/
You'll find that it gives the color using a code starting with a # symbol. You don't need to know what that means, just that it's the color you chose.
Here's an example of me making my own color:
As you can see the only thing I changed was the name of color. Seeing as skyblue isn't on the list, I took the code I got from that website and put that in the place of the name. Also in front of the code was the # symbol to show I was choosing my own color.