Colored signs
Minecraft’s vanilla way of designing signs is either by applying a glow ink sac or a dye to it. But the biggest problem of this is that it changes the look of the entire sign. What if you just want to change the look of a single line or word?
That’s why on the classic server you’re able to freely design your signs. You can use both color codes and formatting codes, making bold or italics text possible too! You can find all color and formatting codes on the Minecraft wiki.