Preferences: Colors

Me → Preferences → Colors sets the colours of name tags, chat, the minimap and your selection beam. Click a colour square to pick a new colour.

General

Option	What it does
My effects (selection beam)	The colour of your selection beam and pointing effects. Use Rainbow cycle for effect color cycles through the rainbow instead.
Show selection beams	Draws the beam from an avatar's hand to what they're editing or touching (yours and everyone else's). Off by default.
Let others see my selection beam	Sends your beam, pointing arc and click sphere to other people. Untick to keep them to yourself.
Name tag font colors	Name tag text colour for Me, Others, Friends, Lindens and Muted (blocked) people.
Name tag background color	The background behind name tags and chat bubbles; Opacity sets how see-through it is.
Minimap dot colors	The dot colour for Me, Others, Friends, Lindens and Muted people on the minimap.
Floater Opacity: Active, Inactive	How see-through windows are when you're using them and when you aren't.

Chat

Chat font colors for your own messages (Me), Others, Friends, System messages, script Errors, Direct messages (sent only to you), messages from objects you Own, web links (URLs), Objects and Lindens.