element-web: riot-desktop doesn't respect system theme

riot-desktop 1.6 from https://packages.riot.im/debian doesn’t respect system theme I have $GTK_THEME=Adwaita:dark and $QT_QPA_PLATFORMTHEME=qt5ct and all gtk2, gtk3, qt4 and qt5 apps that I have are dark, but riot with Match system theme switched on is white.

Chromium (from debian repo) is also white, even if I press Use GTK+ button in it’s setting and it becomes dark, sites doesn’t become dark there. Yes, riot-desktop doesn’t use chromium from debian, but I suspect these effects are common. Possible I don’t set the system theme properly.