Refactor: Button css

[SirrorsMoore1975]

This issue has some Association with issue 93 (#93) as assignee of the said branch find styling a new button using the Button Components are merely impossible unless a refactoring to the Button.css and others css are refactored

Reform the Button.css, so it has a more systematic control and made the css easier to follow or to read.

• Refactor the Button.css and other necessary parts:
  • compare all the button styling and write a default style with those common features in a class reference as the default button styles
  • specific style applies to different buttons and give them each a specific name;
  • apply the style in the necessary React pages and/or components;

Take the following as an ease of references only, class name used should fit the circumstances.

<Button className={"dft_btn_sty back-home"} />