huge black box

remove the display: block; from your clearfix::after class inside your css file to make the box disappear and then check your b_page clearfix class container to find the problem.

why this happened??

dont know. what did you change? (plugins, css, theme-options)

nothing… just uploaded a picture last night… do you think someone is hacking me?

dont think so. check your stylesheets and plugins to find the problem.