Revert "Set theme jekyll-theme-cayman"
Revert "Set theme jekyll-theme-cayman"

This reverts commit a8b63a101cfa5beca2a3aee4afaa71ac93fc8a76.

ripples-alive/ripples-alive.github.io,ripples-alive/ripples-alive.github.io,ripples-alive/ripples-alive.github.io