Missing <ul> and wrong parent

The page style is being affected by incorrect structure. `li` must have a `ul` as a parent (1), and a `ul` must form a list of items with the same logic (2). 

>  (1) **Permitted parent elements**
`ul`, `ol`, `menu`

([Source](http://www.w3.org/TR/html-markup/li.html#li-context))

**P.s**: However, the structure is still incorrect (see 2 topic), I think. But a "big modification" will affect the general style, and  I'll wait a little longer to work on it.