After discussing with some maintainers of Debian documentations, it appears that grey arrows are not great for visibility. In attachment, you can find an archive with red arrows (prev, next and up). They should replace the grey ones.
They are based on the same Tango project icons. The red color used is the color of the Debian logo. The svg files are provided in case someone wants to modify them. Cheers -- Stéphane
red_arrows.tar.lzma
Description: application/lzma