Theme options content Not Responsing to Clicks & Customize Not Working

Hello,

I have discovered that Theme options content is not Responding to Clicks. Also, I cannot customize any theme. Whenever I click customize the theme, a blank page opens and nothing else happens.

This has prevented me from making changes to my blog.

What should I do to be able to go pass the blank page and enter the customize page as well as make the content in Theme Option respond to clicks

The page I need help with: [log in to see the link]