Remove negative left margin from headers in homepage

[pedromvpg]

Its time to remove the negative margin and standardize the website layout.
It was a stylistic move that had no meaning and did not improve the experience.

A lot of people got confused with it.

.row-block h2 {
    /*margin: 2em -55px;*/
    margin: 2em 0px;
} 

[m52go]

Done with #314.