add consistent styling / UI

[e-Steffen]

Value proposition

As a user I want to see and navigate a beautiful, consistent, intuitive design In order to get a awesome UX

Description

• define colors and fonts in styles.js and in components or pages, if useful

  Acceptance criteria

• [ ] a consistent design, simular colors all over the app
• [ ] colors corresponding with the vivaVenture-Logo
• [ ] consistent placing of Link/Buttons
• [ ] implement seperate color-sheme for dark-mode
• [ ] consistent fonts all over the page

  Tasks

• [ ] implement final version of the vivaVenture Logo - the colors of this lead to the colors used in the app
• [ ] define colors for primary, secondary... elements, background, buttons, links
• [ ] define fonts for different content-tye (H1, H2...paragraph)