Stylize FrontPress initial template

[teles]

Actual FrontPress initial template has no css stylesheet.

I guess FrontPres may not cause a good first impression because of that and this may cause some bounce rate for FrontPress.

So this issue aims to stylize the initial template using a css framework already existent. No new css should be created for this project.

Things to solve in this issue:

• [ ] choose a good css framework;
• [ ] apply all css classes to html templates;
• [ ] discover any necessary html content and create issues to them;
• [ ] determine how templates will inject css;

Some nice css frameworks to think about:

• Pure CSS + 15.000 :star:
• Bulma + 11.000 :star:
• Materialize CSS +23.000 :star: