Minor Updates

Indexpage
- minor changes

DNS
- added content
- added accordion
- resize header section
CSS structure change

Added more CSS Structure

assets/css/invictus.css
- tried to expand table of contents
- merge css files
- merge wrong added css code from css.css / main.css

Pls have a closer look to structure, wether it make sense like that or
not!

We should consider also, to integrate something like KSS or cssDOC