Text is hard to read in some emails when using the dark theme

**Describe the bug**
Emails with gray text and white backgrounds can be difficult to read

**To Reproduce**
Steps to reproduce the behavior:
1. Receive an email with a white background and gray text
2. Look at it. It's hard to read!

**Expected behavior**
**The text should be readable like on Android**

**Screenshots (Optional)**

**Device and System information (please complete the following information):**
- Device: Windows computer
- OS Version: Windows 10 Pro N
- App Version: Latest stable version

**Additional information**
Pastebin with the source for the email in question can be linked if you give me an email to send it to.