Change the bullet for the top-level itemization
User bolder fonts
Change the template of the title page
Fix unapplied Beamer color for the title
Fix invalid options for hyperref
Fix complie errors by using \ifx...\else...\fi as default theme does
Fix strange line spacing inserting \par after \insert- commands
Simplify alerted texts

I found changing background color of a part of text is very
uncomfortable because of edges of the colored area.  I think it is only
suit for a separated text such as blocks.