cdlm/vim-colors-solarized — comment on commit 581d16272dc36188f79a19f2a1f16041b9dc67a0
File:  line 0
By skwp:

I experimented last night with creating themes and found it wasn't all that straightforward. In terms of customizing colors, the colorscheme.vim file is not enough to provide. It seems you have to modify Hl.vim in powerline, which has a mapping of colors. I don't know why it's not possible to specify colors directly in the colorscheme. I'm going to try to get some more info from @Lokaltog

https://github.com/skwp/vim-powerline/commit/6172a1177f96fc2cd5d54e404180fe297a5d74c9