Added spans to be better able to translate it.
Initial translation
Fixed Japanese spelling

Fixed Japanese spelling
Fixed Japanese spelling

I have fixed some Japanese spelling.
Please use it if good .
about -> "概要" (English say "overview")
update, lang.js#events
update, lang.js#capters lang.js#about[WIP]
update, code style.
レベル間違えがありました。
Added about section from kaori <usakoyama@gmail.com>