fix: using bootcss cdn instead of mathjax official one because the official cdn has been closed
fix: using bootcss cdn instead of mathjax official one because the official cdn has been closed

cragod/hexo-theme-next,geekrainy/hexo-theme-next,iissnan/hexo-theme-next,Austaras/hexo-theme-next,chaoskyme/hexo-theme-next,mchsinx/hexo-theme-next,chaoskyme/hexo-theme-next