Default Root CSS values

[boosquack]

Fixes #49

[boosquack]

Create Root Variables for the Website

Font

• [x] --default-font-family
• [x] --brand-font-family
• [x] --emphasized-font-family
• [x] --quotation-font-font-family

Others

• [x] colors
• [x] ending tagline
• [x] carousel
• [x] max-width
• [x] button styles
• [x] card styles
• [x] hover effect
• [x] hero
• [x] footer
• [x] section separators
• [x] navigation bar