Slack sidebar theme (Preferences → Themes → Custom)

Column BG, Menu BG, Active Item, Active Item Text, Hover Item, Active Presence, Mention Badge [, Top Nav BG, Top Nav Text, Top Nav Bottom Border]

#18110d,#2c211d,#983a3f,#f0e6d6,#1d1511,#809378,#ba5152,#211814,#e2d3c1,#5c4840