My thoughts on the pavilion colors :
Red is the color of fire and blood, it is associated with energy, war, danger, strength, power, determination as well as passion, desire, and love. This of course is Arnav/ASR. This is the place/the moment that Arnav finally feels her love.
Yellow is the color of sunshine. It's associated with joy, happiness, intellect, and energy. (Only small part of the pavilion is yellow.) We just witnessed a tear of joy from Arnav's eyes when Khushi spoke from her heart.
White is associated with light, goodness, innocence and purity. It is considered to be the color of perfection. White means safety, purity, and cleanliness. White can represent a successful beginning. May her innocent confession cleanse away all the hate. May this be a pure new beginning for Arnav and Khushi.
Let me know what you think.