Board Thread:The Quarters (Q & A)/@comment-76.94.175.201-20140202200431/@comment-7587744-20140211125640

if value < -20    classes += ' color-worst'   else if value < 10    classes += ' color-better'   else    classes += ' color-best'

there is no maximum task value.

You can view it here https://github.com/HabitRPG/habitrpg-shared/blob/develop/script/index.coffee