I'm not sure if everyone's caught onto what I'm doing, but I use lightblue to indicate if my character is saying or thinking (italicized) something, but if I end up controlling another character like an NPC, I will use a different color for their dialog. The reason why colored-text for dialog is to indicate WHO is speaking or when a character is being spoken.
What I would recommend to everyone else is to use an easily-visible color on a black or grey background for dialog portions of text. Normal blue text will not be easily visible, so I would refrain from using that. If you are unsure of what colors will work, I'll type out something and see how you all can see the different colors, but the phrase is "Do you see the color of this text?" If you attempt to try something and it ends up white in the preview, the color-name you chose will not work.
Do you see the color of this text? Black
Do you see the color of this text? Red
Do you see the color of this text? Yellow
Do you see the color of this text? Pink
Do you see the color of this text? Green
Do you see the color of this text? Lightgreen
Do you see the color of this text? Orange
Do you see the color of this text? Purple
Do you see the color of this text? Blue
Do you see the color of this text? Lightblue
Do you see the color of this text? Beige (VERY hard to distinguish this from white on a lot of monitors)
Do you see the color of this text? Brown
Do you see the color of this text? Teal
Do you see the color of this text? Navy
Do you see the color of this text? Maroon
Do you see the color of this text? Limegreen
Do you see the color of this text? White (will change ALL text within the brackets to white)
Do you see the color of this text? Magenta