You can't make adaptive colors in CSS, like a shadow color automatically calculated from another color.
You can use CSS compilers, like CleverCSS, for this.
if you don't want to give each element multiple classes.
But that's the best way to do it.
Double jeopardy is about not being punished for the same crime twice.
No, it's what it says: being put in jeopardy for the same (alleged) crime twice. It's why (in the US) you can appeal your conviction, but the government may not appeal your acquittal. (Supposedly. In practice, if there is sufficient public outcry to string you up, you will be tried again for a "different crime," such as violation of a hate-crime law.)
Waste not, get your budget cut next year.