Created attachment 134733 [details] Screenshot of failing signature SUMMARY When a message is signed using S/MIME (and probably GPG), a small red or green border is put around the message and a small information block is printed above the message (see screenshot). This message is ok for correctly signed messages as one does not want to bother the user with a working infrastructure. However, the failing case should be made more prominent. The message should be made bigger and "brighter". Especially for me (partly color blind), it is almost impossible to get the color "as a byproduct". I have to read the text that can be easily taken for the message of a successful signature. So, I vote to make the text at least 3 times bigger in case of failure and maybe even a thicker border. One could add this as an optional setting for disabled people in the settings if you do not want to clutter the default UI. STEPS TO REPRODUCE 1. Open an email with valid S/MIME signature 2. Open an email with invalid signature OBSERVED RESULT The messages are very close in the text appearance. EXPECTED RESULT More prominent warning of a failed signature check SOFTWARE/OS VERSIONS Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.20.4 KDE Frameworks Version: 5.76.0 Qt Version: 5.15.2