Epic: CSS/Style (General)

[miguelvaara]

Description of the enhancement

Styling is not consistent across Skosmos 3 and there are many redundant rules in the CSS. An audit and refactoring of CSS is needed (see #1597) to keep the file readable and maintainable in the future.

What new functionalities would the enhancement make possible?

• 1 Color scheme configuration (see Colour scheme configuration for Skosmos 3.0 #1505)
• 2 Avoid specifying font sizes in px (see Avoid specifying font sizes in px #1320)
• 3 Setting tab focus correctly (see Tabindex = -1 steals focus #1079)
• 4 Remove redundant/unused rules from CSS
• 5 Correct pagetype classes in CSS and HTML
• 6 Ordering and grouping CSS rules consistently