Following discussion in T15630#15567 we should consider various CSS modernizations with the following goals:

• more modular styles that can be better reused and adapted
• better adaptability for different screen sizes
• more modern look & feel
• having a way to easy develop the CSS without using ./bin/celerity map after every change possible with developer mode
• in a distant future: make Phorge themeable

What could be done and what are possible the next steps?

• Using a modern webfont to have a unified look in every OS: T15630
• Fix and enhance dark mode: T15056
• Consider the use of CSS vars (especially for project colors to decrease such color classes) T15739
• Adapt the size of certain aspects (font, width/visibilty of elements) with media queries (making the classes device-desktop and device-mobile on the body tag maybe unnecessary)
• Planning using extensions to add themes to Phorge
• Integrate the CSS in a modern build/bundle setup