Create a stunning builder gel nail design that embodies a whimsical dive into the cosmos. Utilize rich dark-blue and purple hues to craft a galaxy-inspired base, speckled with glistening silver and gold accents that mimic twinkling stars. Introduce delicate, swirling nebula patterns on select nails using pastel tones to complement the overall cosmic theme. Give emphasis to glossy finishes to highlight the depth of the cosmos depicted on your nails.