Titration results in pink colour, due to the addition of an acid-base indicator Phenolphthalein.
Phenolphthalein turns colourless to brilliant pink as the solution turns from acidic to basic.
It turns pink due to the indicator we employ, phenolphthalein.
It becomes pink at a pH threshold because the lack of a hydrogen ion on an ionizable group affects the frequency of light that the solution absorbs and hence the complementary color that it transmits.