Common CSS next steps

[droshev]

• [x] publish SCSS with the mixins @droshev
• [x] explore the infrastructure
• [ ] Base
• • [ ] normalize (incl. font)
• • [ ] reset (global and comp)
• [x] colors? (it requires some investigation which colors should be exposed)
• [x] spacing
• [x] font-size
• [x] focus (outline/ fake focus)
• [x] border radius
• [ ] animations
• [ ] component metrics
• [x] borders
• [x] shadows
• [x] typography
• [x] flex
• [ ] grid
• [ ] overflow
• [x] display
• [x] screen readers
• [ ] sizing (min and max)
• [x] media queries (break points)
• [x] modifiers for responsive paddings ( e.g. --sm, --md)
• [x] responsive paddings
• [x] documentation - on the main styles nav