I am experiencing exactly the same problem and found an acknowledged upstream bug + fix and other details like cause and backport info here:
https://gitlab.gnome.org/GNOME/evolution/issues/617 On Thu, 21 Nov 2019 16:17:27 +0000 Ben Hutchings < ben.hutchi...@codethink.co.uk> wrote: > Package: evolution > Version: 3.30.5-1.1 > Severity: important > > I recently changed GNOME's theme from Adwaita to Adwaita-dark. This > changed Evolution's default text colour for HTML display from black to > white, but the background colour remains white. (The default colours > in the composer appear to be unchanged.) > > If a received HTML message sets background and text colours, it > displays properly, but if it does not (which seems to be the default > behaviour of Thunderbird) then it is unreadable in Evolution. (A > temporary workaround is to select all text.) > > The same problem affects HighContrast and HighContrastInverse > themes, so this is an accessibility issue. > > Ben. > > -- System Information: > Debian Release: 10.1 > APT prefers stable > APT policy: (990, 'stable'), (500, 'stable-updates'), (500, 'unstable') > Architecture: amd64 (x86_64) > Foreign Architectures: i386, armhf, arm64 > > Kernel: Linux 4.19.0-6-amd64 (SMP w/2 CPU cores) > Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB.UTF-8 (charmap=UTF-8) > Shell: /bin/sh linked to /bin/dash > Init: systemd (via /run/systemd/system) > LSM: AppArmor: enabled > > Versions of packages evolution depends on: > ii dbus 1.12.16-1 > ii evolution-common 3.30.5-1.1 > ii evolution-data-server 3.30.5-1 > ii libc6 2.28-10 > ii libcamel-1.2-62 3.30.5-1 > ii libclutter-gtk-1.0-0 1.8.4-4 > ii libecal-1.2-19 3.30.5-1 > ii libedataserver-1.2-23 3.30.5-1 > ii libevolution 3.30.5-1.1 > ii libglib2.0-0 2.58.3-2+deb10u1 > ii libgtk-3-0 3.24.5-1 > ii libical3 3.0.4-3 > ii libnotify4 0.7.7-4 > ii libsoup2.4-1 2.64.2-2 > ii libwebkit2gtk-4.0-37 2.26.2-1~deb10+1 > ii libxml2 2.9.4+dfsg1-7+b3 > ii psmisc 23.2-1 > > Versions of packages evolution recommends: > ii evolution-plugin-bogofilter 3.30.5-1.1 > ii evolution-plugin-pstimport 3.30.5-1.1 > ii evolution-plugins 3.30.5-1.1 > ii yelp 3.31.90-1 > > Versions of packages evolution suggests: > ii evolution-ews 3.30.5-1 > pn evolution-plugins-experimental <none>
